SpringMVC
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文章目录
SpringMVC
1、回顾MVC
(1) Model（模型层）
角色：处理数据和业务逻辑的“秘书”。
包含内容：
-
POJO/Bean/Domain：数据实体类，描述业务对象。
-
Service：实现核心业务逻辑（如用户注册、订单处理）。
-
Dao（Data Access Object数据库访问对象）：负责数据持久化操作（如数据库增删改查）。
职责：
-
封装业务逻辑和数据操作。
-
独立于视图和控制器，确保数据一致性。
(2) View（视图层）
角色：负责展示数据的“秘书”。
常见技术：JSP、Thymeleaf、HTML、Freemarker 等。
职责：
-
接收来自控制器的数据，渲染用户界面。
-
被动展示：避免包含业务逻辑，仅处理显示逻辑（如数据格式化）。
(3) Controller（控制器层）
角色：协调调度的“司令官”。
职责：
-
接收用户请求（如HTTP请求）。
-
调用Model处理业务逻辑（如调用Service层）。
-
根据处理结果选择合适的视图进行渲染。
-
控制流程，但不直接处理数据或展示逻辑。
2、第一个SpringMVC
-
导入依赖
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.13.2</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>5.2.0.RELEASE</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.2</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> </dependencies> -
导入web支持（ctrl+N快速搜索）
-
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="https://jakarta.ee/xml/ns/jakartaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_6_0.xsd" version="6.0"> <!--1.注册DispatcherServlet--> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--关联一个springmvc的配置文件:【servlet-name】-servlet.xml--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <!--启动级别-1--> <load-on-startup>1</load-on-startup> </servlet> <!--/ 匹配所有的请求；（不包括.jsp）--> <!--/* 匹配所有的请求；（包括.jsp）--> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app> -
springmvc-servlet.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <!-- 处理器映射器 --> <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/> <!-- 处理器适配器 --> <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/> <!--视图解析器:DispatcherServlet给他的ModelAndView--> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="InternalResourceViewResolver"> <!--前缀--> <property name="prefix" value="/WEB-INF/jsp/"/> <!--后缀--> <property name="suffix" value=".jsp"/> </bean> <!--Handler--> <bean id="/hello" class="zhao.yuan.controller.HelloController"/> </beans> -
HelloController
public class HelloController implements Controller { @Override public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception { //ModelAndView 模型和视图 ModelAndView mv = new ModelAndView(); //封装对象，放在ModelAndView中。Model mv.addObject("msg","HelloSpringMVC!"); //封装要跳转的视图，放在ModelAndView中 mv.setViewName("hello"); //: /WEB-INF/jsp/hello.jsp return mv; } } -
hello.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> ${msg} </body> </html> -
遇到的问题：404
加入所有的包（如果项目包过多，从右侧maven中查看对应依赖并引入，全部引入tomcat会报错）
3、SpringMVC运行原理
- **DispatcherServlet：**前端控制器
- HandlerMapping： 处理器映射器
- HandlerAdapter： 处理器适配器
- viewResolver： 视图解析器
图为SpringMVC的一个较完整的流程图，实线表示SpringMVC框架提供的技术，不需要开发者实现，虚线表示需要开发者实现。
- 先申请一个DispatcherServlet，将url传给HandlerMapping
- HandlerMapping根据url查找到具体的Handler（即Controller）（比如说上面代码中的/hello）
- HandlerExecution解析Handler将信息传递给DispatcherServlet
- HandlerAdapter根据DispatcherServlet传递的Handler寻找到对应的适配处理器调用（
SpringMVC的Handler有多种实现方式（Controller，HttpRequestHandler，Servlet等）） - Handler由具体的Controller执行
- Controller将具体的执行信息返回给HandlerAdapter（如：ModelAndView）
- HandlerAdapter将视图逻辑名或模型传递给DispatcherServlet
- DispatcherServlet调用ViewResolver解析信息
- ViewResolver将解析好的信息返回给DispatcherServlet
- DispatcherServlet根据解析好的信息调用具体的视图
4、使用注解开发SpringMVC
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web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <!--1.注册servlet--> <servlet> <servlet-name>springMVC</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!--通过初始化参数指定SpringMVC配置文件的位置，进行关联--> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <!-- 启动顺序，数字越小，启动越早 --> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springMVC</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app> -
springmvc-servlet.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!-- 自动扫描包，让指定包下的注解生效,由IOC容器统一管理 --> <context:component-scan base-package="com.zhao.controller"/> <!-- 让Spring MVC不处理静态资源 --> <mvc:default-servlet-handler/> <!-- 支持mvc注解驱动 在spring中一般采用@RequestMapping注解来完成映射关系 要想使@RequestMapping注解生效 必须向上下文中注册DefaultAnnotationHandlerMapping 和一个AnnotationMethodHandlerAdapter实例 这两个实例分别在类级别和方法级别处理。 而annotation-driven配置帮助我们自动完成上述两个实例的注入。 --> <mvc:annotation-driven/> <!-- 视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> </beans> -
HelloController
package com.zhao.controller; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping("/helloController") public class HelloController { @RequestMapping("/hello") public String hello(Model model){ model.addAttribute("msg","HelloSpringMVC!"); return "hello"; } } -
jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> ${msg} </body> </html>
5、RestFul风格
Restful就是一个资源定位及资源操作的风格。不是标准也不是协议，只是一种风格。基于这个风格设计的软件可以更简洁，更有层次，更安全，更易于实现缓存等机制。
功能
资源：互联网所有的事物都可以被抽象为资源
资源操作：使用POST、DELETE、PUT、GET，使用不同方法对资源进行操作。
分别对应 添加、 删除、修改、查询。
例如：
/order/1 HTTP GET ：得到 id = 1 的 order
/order/1 HTTP DELETE：删除 id = 1的 order
/order HTTP PUT：更新 order
/order HTTP POST：新增 orde
5.1、RequestMapping，GetMapping，PostMapping注解
- SpringMVC 使用@RequestMapping 注解为控制器指定可以处理哪些 URL 请求
- 在控制器的类定义及方法定义处都可标注 @RequestMapping
- 标记在类上：提供初步的请求映射信息。相对于 WEB 应用的根目录
- 标记在方法上：提供进一步的细分映射信息。相对于标记在类上的 URL。
GetMapping注解等价于RequestMapping（value="/test",method=RequestMethod.GET）
PostMapping注解等价于RequestMapping（value="/test",method=RequestMethod.POST）
5.2、PathVariable注解
通过 @PathVariable 可以将 URL中占位符参数绑定到控制器处理方法的参数中：URL 中的 {xxx} 占位符可以通过 @PathVariable(“xxx”) 绑定到操作方法的入参中。
//@PathVariable 注解可以将请求 URL 路径中的请求参数，传递到处理请求方法的入参中
//http://localhost:8080/add/1/3
@PostMapping("/add/{a}/{b}")
public String test3(@PathVariable int a,@PathVariable String b, Model model){
String res = a + b;
model.addAttribute("msg","结果2为"+res);
return "test";
}
6、数据处理与跳转
除了使用视图解析器进行跳转外，还可以使用forward，redirect进行页面跳转
6.1、重定向与转发
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
https://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc
https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 自动扫描包，让指定包下的注解生效,由IOC容器统一管理 -->
<context:component-scan base-package="com.zhao.controller"/>
<!-- 让Spring MVC不处理静态资源 -->
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<!-- 注释掉视图解析器 -->
<!--<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>-->
</beans>
package com.zhao.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
@RequestMapping("/helloController")
public class HelloController {
@RequestMapping("/hello")
public String hello(Model model){
model.addAttribute("msg","HelloSpringMVC!");
//转发
return "forward:/WEB-INF/jsp/hello.jsp";
}
@RequestMapping("/hello1")
public String hello(Model model){
model.addAttribute("msg","HelloSpringMVC1!");
//重定向(访问不到WEB-INF下的内容)
return "redirect:/index.jsp";
}
}
6.2、数据处理
-
参数传递基本数据类型和String时，参数名与请求参数名字一样时，会自动映射
@Controller @RequestMapping("/user") public class UserController { @GetMapping("/t1") // url: /user/t1?name=xxx public String test1(String name, Model model){ // 1. 接收前端参数 System.out.println("接收到前端的参数为"+name); // 2. 将返回的结果传递纷前端， Model model.addAttribute("msg",name); // 3. 视图跳转 return "test"; } } -
参数传递对象时，对象属性名与请求参数名字一样时，才会自动映射
@Data public class User{ private String name; private int age; } @Controller @RequestMapping("/user") public class UserController { @GetMapping("/t2") // url: /user/t2?name1=zhangsan&age=18 public String test1(User user){ System .out.println(user) return "test"; } } >>User(name=null,age=18)
6.3、@RequestParam
指定请求参数名称
@Controller
@RequestMapping("/user")
public class UserController {
@GetMapping("/t1")
// url: /user/t1?username=xxx 参数不一致
public String test1(@RequestParam("username") String name, Model model){
// 1. 接收前端参数
System.out.println("接收到前端的参数为"+name);
// 2. 将返回的结果传递纷前端， Model
model.addAttribute("msg",name);
// 3. 视图跳转
return "test";
}
}
6.4、注解RequestParam与Param的联系
@RequestParam 和 @Param 是两个在不同框架中用于处理参数的注解，它们之间没有直接的继承或实现关系，但在功能上都与"参数绑定"相关。
| 特性 | @RequestParam |
@Param |
|---|---|---|
| 所属框架 | Spring MVC / Spring Web | MyBatis 或 Spring Data JPA |
| 使用位置 | Controller层方法参数 | Mapper/Dao层方法参数 |
| 核心作用 | 指定请求参数名称 | 为SQL语句中的参数起别名 |
6.5、乱码处理
-
可以用Springmvc自带的过滤器
<filter> <filter-name>filter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> -
自带的无法解决用自定义的过滤器
package com.zhao.filter; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletRequestWrapper; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.nio.charset.StandardCharsets; import java.util.Map; /** * 解决get和post请求 全部乱码的过滤器 */ public class GenericEncodingFilter implements Filter { @Override public void destroy() { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { // 处理response的字符编码 HttpServletResponse myResponse = (HttpServletResponse) response; myResponse.setContentType("text/html;charset=UTF-8"); // 转型为与协议相关对象 HttpServletRequest httpServletRequest = (HttpServletRequest) request; // 对request包装增强 HttpServletRequest myrequest = new MyRequest(httpServletRequest); chain.doFilter(myrequest, response); } @Override public void init(FilterConfig filterConfig) throws ServletException { } } // 自定义request对象，HttpServletRequest的包装类 class MyRequest extends HttpServletRequestWrapper { private final HttpServletRequest request; // 是否编码的标记 private boolean hasEncode; // 定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰 public MyRequest(HttpServletRequest request) { super(request);// super必须写 this.request = request; } // 对需要增强方法 进行覆盖 @Override public Map getParameterMap() { // 先获得请求方式 String method = request.getMethod(); if (method.equalsIgnoreCase("post")) { // post请求 try { // 处理post乱码 request.setCharacterEncoding("utf-8"); return request.getParameterMap(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } else if (method.equalsIgnoreCase("get")) { // get请求 Map<String, String[]> parameterMap = request.getParameterMap(); if (!hasEncode) { // 确保get手动编码逻辑只运行一次 for (String parameterName : parameterMap.keySet()) { String[] values = parameterMap.get(parameterName); if (values != null) { for (int i = 0; i < values.length; i++) { // 处理get乱码 values[i] = new String(values[i] .getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8); } } } hasEncode = true; } return parameterMap; } return super.getParameterMap(); } // 取一个值 @Override public String getParameter(String name) { Map<String, String[]> parameterMap = getParameterMap(); String[] values = parameterMap.get(name); if (values == null) { return null; } return values[0]; // 取回参数的第一个值 } // 取所有值 @Override public String[] getParameterValues(String name) { Map<String, String[]> parameterMap = getParameterMap(); String[] values = parameterMap.get(name); return values; } }<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>form.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>filter</filter-name> <filter-class>com.zhao.filter.GenericEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>测试：
form.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <form action="/h/hello" method="post"> <input type="text" name="name"> <input type="submit"> </form> </body> </html>Controller
@Controller public class HelloController { @PostMapping("/h/hello") public String hello(String name,Model model){ System.out.println("name = " + name); model.addAttribute("msg",name); return "hello"; } }web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>form.jsp</welcome-file> </welcome-file-list> <filter> <filter-name>filter</filter-name> <filter-class>com.zhao.filter.GenericEncodingFilter</filter-class> </filter> <filter-mapping> <filter-name>filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
7、@ResponseBody与@RestController
@ResponseBody标注后return “test”不会走视图解析器，返回字符串
@RestController等同于@Controller加@ResponseBody
8、Json
Json在js中是用Json类来进行字符串与Json之间的转换，在java中需要使用工具类
8.1、Jackson Databind依赖
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.20.0</version>
</dependency>
package com.zhao.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private String name;
private int age;
private String sex;
}
package com.zhao.controller;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.zhao.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class UserController {
@RequestMapping("/user")
@ResponseBody
public String json() throws JsonProcessingException {
//创建一个jackson的对象映射器，用来解析数据
ObjectMapper objectMapper = new ObjectMapper();
User user = new User("张三", 18, "男");
//将我们的对象解析成为json格式
String s = objectMapper.writeValueAsString(user);
return s;
}
}
8.2、解决json乱码
- 单个方法解决
@RequestMapping(value = "/user",produces = "application/json;charset=utf-8" )
- 全局解决：springmvc-servlet.xml
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
8.3、json的各种返回形式
8.3.1、集合返回多个对象
@RequestMapping(value = "/user1")
@ResponseBody
public String json1() throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
ArrayList<User> list = new ArrayList<>();
User user = new User("张三", 18, "男");
User user1 = new User("张三", 18, "男");
User user2 = new User("张三", 18, "男");
User user3 = new User("张三", 18, "男");
list.add(user);
list.add(user1);
list.add(user2);
list.add(user3);
String s = objectMapper.writeValueAsString(list);
return s;
}
8.3.2、返回时间
//显示出来是时间戳
@RequestMapping(value = "/user2")
@ResponseBody
public String json2() throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
Date date = new Date();
String s = objectMapper.writeValueAsString(date);
return s;
}
- 纯java解决显示真正时间
@RequestMapping(value = "/user2")
@ResponseBody
public String json2() throws JsonProcessingException {
ObjectMapper objectMapper = new ObjectMapper();
Date date = new Date();
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String s = objectMapper.writeValueAsString(simpleDateFormat.format(date));
return s;
}
-
使用Jackson带的方法
@RequestMapping(value = "/user3") @ResponseBody public String json3() throws JsonProcessingException { ObjectMapper objectMapper = new ObjectMapper(); objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,false); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); objectMapper.setDateFormat(simpleDateFormat); Date date = new Date(); String s = objectMapper.writeValueAsString(date); return s; }
8.4、提取出Json工具类
package com.zhao.utils;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import java.text.SimpleDateFormat;
public class JsonUtils {
public static String getJson(Object object){
return getJson(object,"yyyy-MM-dd HH:mm:ss");
}
public static String getJson(Object object,String simpleDateFormat){
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,false);
SimpleDateFormat simpleDateFormat1 = new SimpleDateFormat(simpleDateFormat);
objectMapper.setDateFormat(simpleDateFormat1);
try {
return objectMapper.writeValueAsString(object);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
@RequestMapping(value = "/user4")
@ResponseBody
public String json4() throws JsonProcessingException {
return JsonUtils.getJson(new Date());
}
8.5、FastJson
fastjson.jar是阿里开发的一款专门用于Java开发的包，可以方便的实现json对象与JavaBean对象的转换，实现JavaBean对象与json字符串的转换，实现json对象与json字符串的转换。实现json的转换方法很多，最后的实现结果都是一样的。
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>2.0.59</version>
</dependency>
package com.blue.controller;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.blue.pojo.User;
import java.util.ArrayList;
import java.util.List;
public class FastJsonDemo {
public static void main(String[] args) {
//创建一个对象
User user1 = new User("秦疆1号", 3, "男");
User user2 = new User("秦疆2号", 3, "男");
User user3 = new User("秦疆3号", 3, "男");
User user4 = new User("秦疆4号", 3, "男");
List<User> list = new ArrayList<User>();
list.add(user1);
list.add(user2);
list.add(user3);
list.add(user4);
System.out.println("*******Java对象 转 JSON字符串*******");
String str1 = JSON.toJSONString(list);
System.out.println("JSON.toJSONString(list)==>"+str1);
String str2 = JSON.toJSONString(user1);
System.out.println("JSON.toJSONString(user1)==>"+str2);
System.out.println("\n****** JSON字符串 转 Java对象*******");
User jp_user1=JSON.parseObject(str2,User.class);
System.out.println("JSON.parseObject(str2,User.class)==>"+jp_user1);
System.out.println("\n****** Java对象 转 JSON对象 ******");
JSONObject jsonObject1 = (JSONObject) JSON.toJSON(user2);
System.out.println("(JSONObject) JSON.toJSON(user2)==>"+jsonObject1.getString("name"));
System.out.println("\n****** JSON对象 转 Java对象 ******");
User to_java_user = JSON.toJavaObject(jsonObject1, User.class);
System.out.println("JSON.toJavaObject(jsonObject1, User.class)==>"+to_java_user);
}
}
9、ssm整合
9.1、创建数据库
CREATE DATABASE `ssmbuild`;
USE `ssmbuild`;
DROP TABLE IF EXISTS `books`;
CREATE TABLE `books` (
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
) ENGINE=INNODB DEFAULT CHARSET=utf8
INSERT INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');
9.2、pom.xml
<dependencies>
<!--Junit-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<!--数据库驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.33</version>
</dependency>
<!-- 数据库连接池 -->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.2</version>
</dependency>
<!--Servlet - JSP -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.2</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!--Mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.6</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.2</version>
</dependency>
<!--Spring-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.39</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.0.RELEASE</version>
</dependency>
</dependencies>
<!--maven静态资源导出问题-->
<build>
<finalName>springmvc-05-ssm</finalName>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
9.3、基本架构和配置文件
建立包结构
- com.zhao.pojo
- com.zhao.dao
- com.zhao.service
- com.zhao.controller
配置文件
- mybatisConfig.xml
- springConfig.xml
- database.properties
mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
</configuration>
springConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
</beans>
database.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=true&useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=root
9.4、Mybatis
- pojo
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Books {
private int bookID;
private String bookName;
private int bookCounts;
private String detail;
}
- mapper
public interface BookMapper {
// 增加一本书
int addBook(Books books);
// 删除一本书,booId和id不一样，所以用个注解转换
int deleteBookById(@Param("bookId") int id);
//更新一本书
int updateBook(Books books);
// 查询一本书
Books queryBookById(@Param("bookId") int id);
// 查询全部的书
List<Books> queryAllBook();
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.zhao.mapper.BookMapper">
<!--增加一个Book-->
<insert id="addBook" parameterType="Books">
insert into ssmbuild.books(bookName,bookCounts,detail)
values (#{bookName}, #{bookCounts}, #{detail})
</insert>
<!--根据id删除一个Book-->
<delete id="deleteBookById" parameterType="int">
delete from ssmbuild.books where bookID=#{bookID}
</delete>
<!--更新Book-->
<update id="updateBook" parameterType="Books">
update ssmbuild.books
set bookName = #{bookName},bookCounts = #{bookCounts},detail = #{detail}
where bookID = #{bookID}
</update>
<!--根据id查询,返回一个Book-->
<select id="queryBookById" resultType="Books">
select * from ssmbuild.books
where bookID = #{bookID}
</select>
<!--查询全部Book-->
<select id="queryAllBook" resultType="Books">
SELECT * from ssmbuild.books
</select>
</mapper>
- service
public interface BookService {
// 增加一本书
int addBook(Books books);
// 删除一本书，不是dao层，所以不用加注解@Para("bookId")
int deleteBookById(int id);
//更新一本书
int updateBook(Books books);
// 查询一本书
Books queryBookById(int id);
// 查询全部的书
List<Books> queryAllBook();
}
public class BookServiceImpl implements BookService{
// service调 dao层：组合Dao
private BookMapper bookMapper;
public void setBookMapper(BookMapper bookMapper) {
this.bookMapper = bookMapper;
}
@Override
public int addBook(Books books) {
return bookMapper.addBook(books);
}
@Override
public int deleteBookById(int id) {
return bookMapper.deleteBookById(id);
}
@Override
public int updateBook(Books books) {
return bookMapper.updateBook(books);
}
@Override
public Books queryBookById(int id) {
return bookMapper.queryBookById(id);
}
@Override
public List<Books> queryAllBook() {
return bookMapper.queryAllBook();
}
}
9.5、Spring
-
spring-dao.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd"> <!-- 配置整合mybatis --> <!-- 1.关联数据库文件 --> <context:property-placeholder location="classpath:database.properties"/> <!-- 2.数据库连接池 --> <!--数据库连接池 dbcp 半自动化操作 不能自动连接 c3p0 自动化操作（自动的加载配置文件 并且设置到对象里面） --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <!-- 配置连接池属性 --> <property name="driverClass" value="${jdbc.driver}"/> <property name="jdbcUrl" value="${jdbc.url}"/> <property name="user" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> <!-- c3p0连接池的私有属性 --> <property name="maxPoolSize" value="30"/> <property name="minPoolSize" value="10"/> <!-- 关闭连接后不自动commit --> <property name="autoCommitOnClose" value="false"/> <!-- 获取连接超时时间 --> <property name="checkoutTimeout" value="10000"/> <!-- 当获取连接失败重试次数 --> <property name="acquireRetryAttempts" value="2"/> </bean> <!-- 3.配置SqlSessionFactory对象 --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <!-- 注入数据库连接池 --> <property name="dataSource" ref="dataSource"/> <!-- 配置MyBaties全局配置文件:mybatis-config.xml --> <property name="configLocation" value="classpath:mybatisConfig.xml"/> </bean> <!-- 4.配置扫描Dao接口包，动态实现Dao接口注入到spring容器中 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <!-- 注入sqlSessionFactory --> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/> <!-- 给出需要扫描Dao接口包 --> <property name="basePackage" value="com.zhao.mapper"/> </bean> </beans> -
spring-service.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!-- 1. 扫描service相关的bean --> <context:component-scan base-package="com.zhao.service" /> <!--2. BookServiceImpl注入到IOC容器中--> <bean id="BookServiceImpl" class="com.zhao.service.BookServiceImpl"> <property name="bookMapper" ref="bookMapper"/> </bean> <!-- 3. 配置事务管理器 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <!-- 注入数据库连接池 --> <property name="dataSource" ref="dataSource" /> </bean> </beans> -
springConfig.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <import resource="classpath:spring-dao.xml"/> <import resource="classpath:spring-service.xml"/> <import resource="classpath:spring-mvc.xml"/> </beans>
9.6、SpringMVC
-
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <!--DispatcherServlet--> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <!--一定要注意:我们这里加载的是总的配置文件，之前被这里坑了！--> <param-value>classpath:springConfig.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!--乱码过滤 encodingFilter--> <filter> <filter-name>encodingFilter</filter-name> <filter-class> org.springframework.web.filter.CharacterEncodingFilter </filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>encodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!--Session过期时间--> <session-config> <session-timeout>15</session-timeout> </session-config> </web-app> -
spring-mvc.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd"> <!-- 配置SpringMVC --> <!-- 1.开启SpringMVC注解驱动 --> <mvc:annotation-driven /> <!-- 2.静态资源默认servlet配置--> <mvc:default-servlet-handler/> <!-- 3.配置jsp 显示ViewResolver视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> <!-- 4.扫描web相关的bean --> <context:component-scan base-package="com.zhao.controller" /> </beans>
9.7、注意点
-
记得添加lib
-
问题：bean不存在（500）
步骤：
1、查看这个bean注入是否成功！（用注解判断）
2、Junit单元测试，看我们的代码是否能够查询出来结果！@Test public void test(){ ApplicationContext context = new ClassPathXmlApplicationContext("springConfig.xml"); BookService bookServiceImpl = context.getBean("BookServiceImpl", BookServiceImpl.class); List<Books> books = bookServiceImpl.queryAllBook(); for (Books book : books) { System.out.println(book); } }3、问题，一定不在我们的底层，是spring出了问题！
4、SpringMVC，整合的时候没调用到我们的service.层的beanspringConfig.xml没有注入bean
web.xml中，我们也绑定过配置文件！发现问题，我们配置的是Spring-mvc.Xml这里面确实没有service bean,所以报空指针
所以，在web.xml中classpath:springConfig.xml而不是classpath:spring-mvc.xml
9.8、查询书籍
index.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>首页</title>
<style>
a{
text-decoration: none;
color: blue;
font-size: 18px;
}
h3{
width: 180px;
height: 38px;
margin: 100px auto;
text-align: center;
line-height: 38px;
background: deepskyblue;
border-radius: 5px;
}
</style>
</head>
<body>
<h3>
<a href="${pageContext.request.contextPath}/book/allBook">进入书籍页面</a>
</h3>
</body>
</html>
查找BootStrap CDN，搜索
<!-- 新 Bootstrap 核心 CSS 文件 -->
<link href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
allbook.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>书籍展示</title>
<!-- 新 Bootstrap 核心 CSS 文件 -->
<link href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<!-- jQuery文件。务必在bootstrap.min.js 之前引入 -->
<script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>书籍列表 —— 显示所有书籍</small>
</h1>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<table class="table table-hover table-striped">
<thead>
<tr>
<th>书籍编号</th>
<th>书籍名字</th>
<th>书籍数量</th>
<th>书籍详情</th>
<th>操作</th>
</tr>
</thead>
<%-- 书籍从数据库中查询出来，从这个List中遍历出来：foreach --%>
<tbody>
<%-- <c:forEach var="book" items="${requestScope.get('list')}">--%>
<c:forEach var="book" items="${requestScope.get('list')}">
<tr>
<td>${book.getBookID()}</td>
<td>${book.getBookName()}</td>
<td>${book.getBookCounts()}</td>
<td>${book.getDetail()}</td>
</tr>
</c:forEach>
</tbody>
</table>
</div>
</div>
</div>
</body>
</html>
9.9、添加书籍
-
allBook页面添加按钮
<div class="row"> <div class="col-md-4 column"> <a class="btn btn-primary" href="${pageContext.request.contextPath}/book/toAddBook">新增书籍</a> </div> </div> -
Controller添加对应方法
@RequestMapping("toAddBook") public String toAddBook(){ return "addBook"; } @RequestMapping("addBook") public String addBook(Books book){ bookService.addBook(book); //用户刷新页面（F5）会导致表单重复提交，订单被多次保存。 // 表单提交必须使用重定向，核心原因是防止重复提交和数据重复处理 return "redirect:queryAll"; } -
addBook页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <!-- 引入 Bootstrap --> <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/> </head> <body> <div class="container"> <div class="row clearfix"> <div class="col-md-12 column"> <div class="page-header"> <h1> <small>书籍列表-----新增书籍</small> </h1> </div> </div> </div> <form action="${pageContext.request.contextPath}/book/addBook" method="post"> <div class="form-group"> <label>书籍名称：</label> <input type="text" name="bookName" class="form-control" required> </div> <div class="form-group"> <label>书籍数量：</label> <input type="text" name="bookCounts" class="form-control" required> </div> <div class="form-group"> <label>书籍详情：</label> <input type="text" name="detail" class="form-control" required> </div> <div class="form-group"> <input type="submit" class="form-control" value="添加"> </div> </form> </div> </body> </html>
9.10、修改删除书籍
-
allBook页面添加操作
<tbody> <c:forEach var="book" items="${list}"> <tr> <td>${book.bookID}</td> <td>${book.bookName}</td> <td>${book.bookCounts}</td> <td>${book.detail}</td> <td> <a href="${pageContext.request.contextPath}/book/toUpdateBook/${book.bookID}">修改</a> <a href="${pageContext.request.contextPath}/book/deleteBook/${book.bookID}">删除</a> </td> </tr> </c:forEach> -
Controller写相关方法
//跳转到修改页面 @RequestMapping("toUpdateBook/{bookID}") public String toUpdateBook(@PathVariable("bookID") int id,Model model){ Books books = bookService.queryBookById(id); // System.out.println(books); model.addAttribute("book",books); return "updateBook"; } //修改 @RequestMapping("updateBook") public String updateBook(Books books){ // System.out.println(books); bookService.updateBook(books); return "redirect:queryAll"; } //删除 @RequestMapping("deleteBook/{bookID}") public String deleteBook(@PathVariable("bookID") int id){ bookService.deleteBookById(id); return "redirect:/book/queryAll"; } -
updateBook页面
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <!-- 引入 Bootstrap --> <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet"/> </head> <body> <div class="container"> <div class="row clearfix"> <div class="col-md-12 column"> <div class="page-header"> <h1> <small>书籍列表-----修改书籍</small> </h1> </div> </div> </div> <form action="${pageContext.request.contextPath}/book/updateBook" method="post"> <!--隐藏域存id，将id传给后端执行sql--> <input type="hidden" name="bookID" value="${book.bookID}"> <div class="form-group"> <label>书籍名称：</label> <input type="text" name="bookName" class="form-control" value="${book.bookName}" required> </div> <div class="form-group"> <label>书籍数量：</label> <input type="text" name="bookCounts" class="form-control" value="${book.bookCounts}" required> </div> <div class="form-group"> <label>书籍详情：</label> <input type="text" name="detail" class="form-control" value="${book.detail}" required> </div> <div class="form-group"> <input type="submit" class="form-control" value="修改"> </div> </form> </div> </body> </html>
9.11、搜索框模糊查询
-
allbook页面添加搜索框表单
<div class="row"> <div class="col-md-4 column"> <a class="btn btn-primary" href="${pageContext.request.contextPath}/book/toAddBook">新增书籍</a> </div> <div class="col-md-8 column" style="text-align: right"> <form action="${pageContext.request.contextPath}/book/queryByBookName" method="post" class="form-inline"> <label> <input type="text" name="bookName" placeholder="请输入要查询书籍的名称" class="form-control"> </label> <label> <input type="submit" value="查询" class="btn btn-primary"> </label> </form> </div> </div> -
Controller增加方法
//根据书籍名称查询 @RequestMapping("queryByBookName") public String queryBookByName(String bookName, Model model) { List<Books> books = bookService.queryBookByName(bookName); model.addAttribute("list", books); return "allBook"; } -
service，mapper层添加
@Override public List<Books> queryBookByName(String bookName) { if (bookName == null || bookName.equals("")){ return bookMapper.queryAllBook(); } return bookMapper.queryBookByName(bookName); }<select id="queryBookByName" resultType="com.zhao.pojo.Books"> select * from ssmbuild.books where bookName like concat("%",#{bookName},"%") </select>
10、Ajax
- AJAX 是一种不发生页面跳转、异步载入内容并改写页面内容的技术。
- XMLHttpRequest对象是AJAX中非常重要的对象，所有的AJAX操作都是基于该对象的。
- XMLHttpRequest对象用来封装请求报文，我们向服务器发送的请求信息全部都需要封装到该对象中。
- jQuery 提供多个与 AJAX 有关的方法。
- jquery常用的有 . a j a x （可以设置 p o s t 或 g e t ） , .ajax（可以设置post或get）, .ajax（可以设置post或get）,.get,$.post三种
jQuery.ajax(...)
部分参数：
url：请求地址
type：请求方式，GET、POST（1.9.0之后用method）
headers：请求头
data：要发送的数据
contentType：即将发送信息至服务器的内容编码类型(默认: "application/x-www-form-urlencoded; charset=UTF-8")
async：是否异步
timeout：设置请求超时时间（毫秒）
beforeSend：发送请求前执行的函数(全局)
complete：完成之后执行的回调函数(全局)
success：成功之后执行的回调函数(全局)
error：失败之后执行的回调函数(全局)
accepts：通过请求头发送给服务器，告诉服务器当前客户端可接受的数据类型
dataType：将服务器端返回的数据转换成指定类型
"xml": 将服务器端返回的内容转换成xml格式
"text": 将服务器端返回的内容转换成普通文本格式
"html": 将服务器端返回的内容转换成普通文本格式，在插入DOM中时，如果包含JavaScript标签，则会尝试去执行。
"script": 尝试将返回值当作JavaScript去执行，然后再将服务器端返回的内容转换成普通文本格式
"json": 将服务器端返回的内容转换成相应的JavaScript对象
"jsonp": JSONP 格式使用 JSONP 形式调用函数时，如 "myurl?callback=?" jQuery 将自动替换 ? 为正确的函数名，以执行回调函数
10.1、入门
-
搭建springmvc框架，web.xml,spring-mvc.xml
-
导入jquery
-
controller编写请求
@RestController public class AjaxController { @RequestMapping("/ajax") public void ajax(String name, HttpServletResponse response) throws Exception { if ("admin".equals(name)) { response.getWriter().print("true"); } else { response.getWriter().print("false"); } } } -
前端页面
<!DOCTYPE html> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <script src="${pageContext.request.contextPath}/static/js/jquery-3.7.1.js"></script> <script> function a(){ $.post({ //所有参数： //url：将待载入也免得URL地址，json //data：待发送Key/value参数 //success：载入成功时回调的函数 //data封装了服务器返回的数据 //status：状态 url:"${pageContext.request.contextPath}/ajax", data:{"name":$("#name").val()}, success:function (data){ console.log(data); console.log(status); } }) } </script> </head> <body> <p>跳转</p> <p> <%--οnblur=""失去焦点产生事件--%> <input type="text" id="name" onblur="a()"> </p> </body> </html>
10.2、Ajax异步加载数据
-
User
@Data @NoArgsConstructor @AllArgsConstructor public class User { private String name; private int age; private String sex; } -
Controller
@RequestMapping("/a2") public List<User> a2(){ ArrayList<User> list = new ArrayList<>(); list.add(new User("张三",18,"男")); list.add(new User("张三",18,"男")); list.add(new User("张三",18,"男")); list.add(new User("张三",18,"男")); return list; } -
页面显示
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> <script src="${pageContext.request.contextPath}/static/js/jquery-3.7.1.js"></script> <script> $(function () { $("#btn").click(function () { $.post({ url:"${pageContext.request.contextPath}/a2", success:function (data){ console.log(data); var html = ""; for (let i = 0; i < data.length; i++) { html += "<tr>" + "<td>" + data[i].name + "</td>" + "<td>" + data[i].age + "</td>" + "<td>" + data[i].sex + "</td>" + "</tr>" } $("#tbody").html(html); } }) }) }) </script> </head> <body> <input type="button" value="点击" id="btn"> <table> <tr> <td>名字</td> <td>年龄</td> <td>性别</td> </tr> <tbody id="tbody"> </tbody> </table> </body> </html>
10.3、Ajax表单验证
-
Controller
@RequestMapping("/a3") public String a3(String username,String pwd) { String msg = ""; if (username != null) { if ("admin".equals(username)) { msg = "true"; }else { msg = "error"; } } if (pwd != null){ if ("111".equals(pwd)) { msg = "true"; }else { msg = "error"; } } return msg; } -
login.jsp
<html> <head> <title>Title</title> <script src="${pageContext.request.contextPath}/static/js/jquery-3.7.1.js"></script> <script> function a1() { $.post({ url:"${pageContext.request.contextPath}/a3", data:{"username":$("#username").val()}, success:function (data){ console.log(data); console.log(data.toString()) if (data.toString()=="true"){ $("#userInfo").css("color","green") }else { $("#userInfo").css("color","red") } $("#userInfo").html(data); } }) } function a2() { $.post({ url:"${pageContext.request.contextPath}/a3", data:{"pwd":$("#pwd").val()}, success:function (data){ console.log(data); console.log(data.toString()) if (data.toString()=="true"){ $("#pwdInfo").css("color","green") }else { $("#pwdInfo").css("color","red") } $("#pwdInfo").html(data); } }) } </script> </head> <body> <p> 用户名：<input type="text" id="username" onblur="a1()"> <span id="userInfo"></span> </p> <p> 密 码：<input type="text" id="pwd" onblur="a2()"> <span id="pwdInfo"></span> </p> </body> </html>
11、拦截器
11.1、基本使用
拦截器是AOP思想的具体应用，类似于过滤器Filter
过滤器
- servlet规范中的一部分，所有javaweb都可以使用
- url-pattern中配置了/*之后，可以对所有要访问的资源进行拦截
拦截器
只有使用了SpringMVC框架的工程才能使用
拦截器只会拦截控制器中的请求，如果访问jsp/html/js/css/image不会拦截
-
自定义拦截器实现HandlerInterceptor接口
public class MyInterceptor implements HandlerInterceptor { //return true 放行，false 拦截 @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("========执行前========"); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { System.out.println("========执行后========"); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { System.out.println("========清理========"); } } -
spring-mvc.xml配置拦截器
<!--拦截器配置--> <mvc:interceptors> <mvc:interceptor> <!--拦截所有请求，包括这个请求下的所有请求,/t/a/aa/aaa--> <mvc:mapping path="/**"/> <bean class="com.zhao.interceptor.MyInterceptor"/> </mvc:interceptor> </mvc:interceptors> -
Controller
@RestController public class InterceptorController { @RequestMapping("/i") public String interceptor(){ System.out.println("InterceptorController执行了"); return "ok"; } }
11.2、登录拦截
-
login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>用户登录</title> </head> <body> <div class="login-container"> <h2>用户登录</h2> <form action="${pageContext.request.contextPath}/doLogin" method="post"> <div class="form-group"> <label for="username">用户名:</label> <input type="text" id="username" name="username" required> </div> <div class="form-group"> <label for="password">密码:</label> <input type="password" id="password" name="password" required> </div> <div class="form-group"> <button type="submit">登录</button> </div> </form> </div> </body> </html> -
success.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>用户仪表板</title></head> <body> <div class="dashboard-container"> <div class="header"> <h2>欢迎来到用户仪表板</h2> <div class="user-info"> 当前用户: <strong>${username}</strong> <a href="${pageContext.request.contextPath}/logout" class="logout-btn">退出登录</a> </div> </div> </div> </body> </html> -
Controller
// 显示登录页面 @RequestMapping(value = "/login") public String showLoginPage() { return "login"; } // 处理登录请求 @RequestMapping(value = "/doLogin", method = RequestMethod.POST) public String login(@RequestParam("username") String username, @RequestParam("password") String password, HttpServletRequest request, Model model) { // 简单的用户验证（实际项目中应该查询数据库） if ("admin".equals(username) && "123456".equals(password)) { // 登录成功，将用户信息存入session HttpSession session = request.getSession(); session.setAttribute("username", username); session.setAttribute("loginTime", System.currentTimeMillis()); return "redirect:/success"; } else { // 登录失败 return "login"; } } // 显示仪表板（需要登录才能访问） @RequestMapping(value = "/success", method = RequestMethod.GET) public String showDashboard(HttpServletRequest request, Model model) { HttpSession session = request.getSession(); String username = (String) session.getAttribute("username"); model.addAttribute("username", username); return "success"; } // 退出登录 @RequestMapping(value = "/logout", method = RequestMethod.GET) public String logout(HttpServletRequest request) { // 清除session HttpSession session = request.getSession(); session.invalidate(); return "redirect:/login"; } -
拦截器
public class LoginInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { // 获取请求的URL String url = request.getRequestURI(); // 登录页面和登录请求不拦截 if (url.contains("/login") || url.contains("/doLogin")) { return true; } // 获取session HttpSession session = request.getSession(); String username = (String) session.getAttribute("username"); // 如果session中存在用户信息，则放行 if (username != null && !username.isEmpty()) { return true; } // 不符合条件的，跳转到登录页面 request.getRequestDispatcher("/WEB-INF/jsp/login.jsp").forward(request, response); return false; } } -
配置文件配置
<!--拦截器配置--> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/**"/> <mvc:exclude-mapping path="/login"/> <mvc:exclude-mapping path="/doLogin"/> <bean class="com.zhao.interceptor.LoginInterceptor"/> </mvc:interceptor> </mvc:interceptors>
12、文件上传
- 导入文件上传的jar包，commons-fileupload ， Maven会自动帮我们导入他的依赖包 commons-io包；
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
<!--servlet-api导入高版本的-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
-
配置bean：multipartResolver
【注意！！！这个bena的id必须为：multipartResolver ， 否则上传文件会报400的错误！在这里栽过坑,教训！】
<!--文件上传配置--> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 --> <property name="defaultEncoding" value="utf-8"/> <!-- 上传文件大小上限，单位为字节（10485760=10M） --> <property name="maxUploadSize" value="10485760"/> <property name="maxInMemorySize" value="40960"/> </bean> -
编写前端页面
<form action="/upload" enctype="multipart/form-data" method="post"> <input type="file" name="file"/> <input type="submit" value="upload"> </form> -
Controller
@Controller public class FileController { //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象 //批量上传CommonsMultipartFile则为数组即可 @RequestMapping("/upload") public String fileUpload(@RequestParam("file") CommonsMultipartFile file , HttpServletRequest request) throws IOException { //获取文件名 : file.getOriginalFilename(); String uploadFileName = file.getOriginalFilename(); //如果文件名为空，直接回到首页！ if ("".equals(uploadFileName)){ return "redirect:/index.jsp"; } System.out.println("上传文件名 : "+uploadFileName); //上传路径保存设置 String path = request.getServletContext().getRealPath("/upload"); //如果路径不存在，创建一个 File realPath = new File(path); if (!realPath.exists()){ realPath.mkdir(); } System.out.println("上传文件保存地址："+realPath); InputStream is = file.getInputStream(); //文件输入流 OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流 //读取写出 int len=0; byte[] buffer = new byte[1024]; while ((len=is.read(buffer))!=-1){ os.write(buffer,0,len); os.flush(); } os.close(); is.close(); return "redirect:/index.jsp"; } }采用file.Transto 来保存上传的文件
@RequestMapping("/upload2") public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException { //上传路径保存设置 String path = request.getServletContext().getRealPath("/upload"); File realPath = new File(path); if (!realPath.exists()){ realPath.mkdir(); } //上传文件地址 System.out.println("上传文件保存地址："+realPath); //通过CommonsMultipartFile的方法直接写文件（注意这个时候） file.transferTo(new File(realPath +"/"+ file.getOriginalFilename())); return "redirect:/index.jsp"; }
13、文件下载
文件下载步骤：
1、设置 response 响应头
2、读取文件 – InputStream
3、写出文件 – OutputStream
4、执行操作
5、关闭流 （先开后关）
代码实现：
@RequestMapping(value="/download")
public String downloads(HttpServletResponse response ,HttpServletRequest request) throws Exception{
//要下载的图片地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "基础语法.jpg";
//1、设置response 响应头
response.reset(); //设置页面不缓存,清空buffer
response.setCharacterEncoding("UTF-8"); //字符编码
response.setContentType("multipart/form-data"); //二进制传输数据
//设置响应头
response.setHeader("Content-Disposition",
"attachment;fileName="+URLEncoder.encode(fileName, "UTF-8"));
File file = new File(path,fileName);
//2、 读取文件--输入流
InputStream input=new FileInputStream(file);
//3、 写出文件--输出流
OutputStream out = response.getOutputStream();
byte[] buff =new byte[1024];
int index=0;
//4、执行 写出操作
while((index= input.read(buff))!= -1){
out.write(buff, 0, index);
out.flush();
}
out.close();
input.close();
return null;
}
.exists()){
realPath.mkdir();
}
System.out.println(“上传文件保存地址：”+realPath);
InputStream is = file.getInputStream(); //文件输入流
OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流
//读取写出
int len=0;
byte[] buffer = new byte[1024];
while ((len=is.read(buffer))!=-1){
os.write(buffer,0,len);
os.flush();
}
os.close();
is.close();
return "redirect:/index.jsp";
}
}
**采用file.Transto 来保存上传的文件**
```java
@RequestMapping("/upload2")
public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
//上传路径保存设置
String path = request.getServletContext().getRealPath("/upload");
File realPath = new File(path);
if (!realPath.exists()){
realPath.mkdir();
}
//上传文件地址
System.out.println("上传文件保存地址："+realPath);
//通过CommonsMultipartFile的方法直接写文件（注意这个时候）
file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
return "redirect:/index.jsp";
}
13、文件下载
文件下载步骤：
1、设置 response 响应头
2、读取文件 – InputStream
3、写出文件 – OutputStream
4、执行操作
5、关闭流 （先开后关）
代码实现：
@RequestMapping(value="/download")
public String downloads(HttpServletResponse response ,HttpServletRequest request) throws Exception{
//要下载的图片地址
String path = request.getServletContext().getRealPath("/upload");
String fileName = "基础语法.jpg";
//1、设置response 响应头
response.reset(); //设置页面不缓存,清空buffer
response.setCharacterEncoding("UTF-8"); //字符编码
response.setContentType("multipart/form-data"); //二进制传输数据
//设置响应头
response.setHeader("Content-Disposition",
"attachment;fileName="+URLEncoder.encode(fileName, "UTF-8"));
File file = new File(path,fileName);
//2、 读取文件--输入流
InputStream input=new FileInputStream(file);
//3、 写出文件--输出流
OutputStream out = response.getOutputStream();
byte[] buff =new byte[1024];
int index=0;
//4、执行 写出操作
while((index= input.read(buff))!= -1){
out.write(buff, 0, index);
out.flush();
}
out.close();
input.close();
return null;
}
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