目录
完整代码在这
Spring MVC对JSON数据格式的支持非常好，配置完成后什么都不用管靠注解就可以轻松返回JSON格式的数据。
Spring 对JSON的支持有三种方式，下面会一一介绍，在此之前先是一些准备工作。
一、配置文件应该添加什么东西
Maven配置文件应该添加哪些包 除了Spring MVC的核心包之外，还要加上JSON相关的依赖<?xml version="1.0" encoding="UTF-8"?><project xmlns="/POM/4.0.0" xmlns:xsi="/2001/XMLSchema-instance"xsi:schemaLocation="/POM/4.0.0 /xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.learn.springmvc</groupId><artifactId>SpringMVCJSONDemo</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><name>SpringMVCJSONDemo Maven Webapp</name><!-- FIXME change it to the project's website --><url></url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><piler.source>1.7</piler.source><piler.target>1.7</piler.target></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency><dependency><groupId>javax.servlet</groupId><artifactId>servlet-api</artifactId><version>2.5</version></dependency><!--配置SpringMVC包--><dependency><groupId>org.springframework</groupId><artifactId>spring-core</artifactId><version>4.3.11.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-beans</artifactId><version>4.3.11.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>4.3.11.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-web</artifactId><version>4.3.11.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>4.3.11.RELEASE</version></dependency><!--配置JSON包--><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.8.10</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-core</artifactId><version>2.8.10</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>2.8.0</version></dependency></dependencies><build><finalName>SpringMVCJSONDemo</finalName><pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --><plugins><plugin><artifactId>maven-clean-plugin</artifactId><version>3.1.0</version></plugin><!-- see /ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging --><plugin><artifactId>maven-resources-plugin</artifactId><version>3.0.2</version></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><version>3.8.0</version></plugin><plugin><artifactId>maven-surefire-plugin</artifactId><version>2.22.1</version></plugin><plugin><artifactId>maven-war-plugin</artifactId><version>3.2.2</version></plugin><plugin><artifactId>maven-install-plugin</artifactId><version>2.5.2</version></plugin><plugin><artifactId>maven-deploy-plugin</artifactId><version>2.8.2</version></plugin></plugins></pluginManagement></build></project>复制代码
Spring配置文件中除了和视图相关的bean要配置外，还需要配置和JSON有关的bean
<?xml version="1.0" encoding="UTF-8"?><beans xmlns="/schema/beans"xmlns:xsi="/2001/XMLSchema-instance" xmlns:aop="/schema/aop"xmlns:context="/schema/context"xmlns:mvc="/schema/mvc"xsi:schemaLocation="/schema/beans /schema/beans/spring-beans.xsd /schema/aop /schema/aop/spring-aop.xsd /schema/context /schema/context/spring-context.xsd /schema/mvc /schema/mvc/spring-mvc.xsd"><context:component-scan base-package="com.learn.Controller com.learn.model"/><context:annotation-config/><!--这个一定要加--><mvc:annotation-driven /><!--和视图路径有关的bean--><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix"><value>/</value></property><property name="suffix"><value>.jsp</value></property></bean><!--和json有关的bean--><bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver"><property name="order" value="1" /><property name="defaultViews"><list><!-- Json视图 --><bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"/></list></property></bean></beans>复制代码
二、创建model类
package com.learn.model;public class User {private String name;private String id;private String email;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getId() {return id;}public void setId(String id) {this.id = id;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}}复制代码
三、返回JSON数据的方式
在讲三种方式之前，先创建一个Controller
package com.learn.Controller;import com.learn.model.User;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;@RequestMapping("json")@Controllerpublic class UserController {}复制代码
1、@ResponseBody方式、
直接在控制器内加上下面的代码：
@RequestMapping(value = "/user/first")@ResponseBodypublic User getUserJSONInfo(){System.out.println("请求JSON数据！！！");User user = new User();user.setName("today");user.setId("10086");user.setEmail("123@");return user;}复制代码
在上面的代码中，有@ResponseBody注解，表明此方法返回的不是视图，而直接是responseBody
这个方法返回的是User类型的对象，但是在运行过程中会被自动转变成JSON对象返回给前端
运行结果：
2、使用 ResponseEntity
在控制器中加上如下代码：
@RequestMapping(value="/user/second")public ResponseEntity<User> getUserJSONInfo2(){User user = new User();user.setId("10086111");user.setName("second");user.setEmail("second@");return new ResponseEntity<User>(user, HttpStatus.OK);}复制代码
3、httpServletResponse
这个方法很简单，就是自己把返回格式设成json格式就可以了
在控制器中加入如下代码：
@RequestMapping(value = "/user/third")public void getUserJSONInfo3(HttpServletResponse response) throws IOException {response.setContentType("application/json");response.getWriter().println("{\"name\":\"third\",\"id\":\"10086\",\"email\":\"third@\"}");复制代码
运行结果：
4、使用 返回多个JSON对象
代码：
@RequestMapping(value = "/user/forth")@ResponseBodypublic Map<String, Object> getUserJSONInfo4(){User user = new User();user.setName("forth");user.setId("10086");user.setEmail("forth@");Map<String, Object> map = new HashMap<String, Object>();map.put("users", user);map.put("info", "some info");map.put("time", "now");return map;}复制代码
运行结果：
