Spring MVC返回JSON数据

出处:http://blog.csdn.net/yh_zeng2 http://blog.csdn.net/yh_zeng2/article/details/77074037

Spring MVC对JSON数据的返回提供了良好的支持，现在介绍三种方式：

• 使用@ResponseBody标注
• 使用ResponseEntity
• 使用HttpServletResponse对象返回JSON数据

注意：方式一和方式二，都依赖jackson-databind-版本号.jar、jackson-annotations-版本号.jar、jackson-core-版本号.jar 这几个jar包，也就是项目要导入这三个jar包，并且要定义Json视图解析器！！

例子：

pom.xml文件中添加以下内容，让项目添加所需要的相关的jackson包：

     jackson-annotations-版本号.jar
     jackson-core-版本号.jar
      例如：jackson-databind-2.5.4.jar，就依赖jackson-annotations-2.5.0.jar和jackson-core-2.5.4.jar这两个包
–>
<dependency>
    <groupId>com.fasterxml.jackson.coregroupId>
    <artifactId>jackson-databindartifactId>
    <version>2.5.4version>
dependency>

    com.fasterxml.jackson.core
    jackson-databind
    2.5.4

Json视图解析器：

   <bean class=“org.springframework.web.servlet.view.ContentNegotiatingViewResolver”>
    <property name=“order” value=“1” />
    <property name=“defaultViews”>
        <list>

            <bean class=“org.springframework.web.servlet.view.json.MappingJackson2JsonView”/>
        list>
    property>
bean>

ReturnJsonController.java：

package edu.mvcdemo.controller;

import javax.servlet.http.HttpServletResponse;
import org.springframework.context.annotation.Scope;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import edu.mvcdemo.model.User;

/**
 * @编写人： yh.zeng
 * @编写时间：2017-8-7 下午10:12:26
 * @文件描述: Controller返回JSON数据的demo
 */
@Controller
@Scope(value=“singleton”) //只实例化一个bean对象（即每次请求都使用同一个bean对象），默认是singleton
public class ReturnJsonController {

    /**
     * 方式一：使用@ResponseBody标注
     * @param userId
     * @return
     */
    @ResponseBody
    @RequestMapping(value=“/jsontype/view1/users/{userId}”, method=RequestMethod.GET)
    public User getUserInJson(@PathVariable(“userId”) Integer userId){
        User user = new User();
        user.setNo(userId);
        user.setUserName(”user”+userId);
        return user;
    }

    /**
     * 方式二：使用ResponseEntity
     * @param userId
     * @return
     */
    @RequestMapping(value=“/jsontype/view2/users/{userId}”, method=RequestMethod.GET)
    public ResponseEntity getUserInJson2(@PathVariable(“userId”) Integer userId){
        User user = new User();
        user.setNo(userId);
        user.setUserName(”user”+userId);
        return new ResponseEntity(user, HttpStatus.OK);
    }

    /**
     * 方式三：使用HttpServletResponse对象返回JSON数据
     * @param userId
     * @param response
     * @throws Exception
     */
    @RequestMapping(value=“/jsontype/view3/users/{userId}”, method=RequestMethod.GET)
    public void getUserInJson3(@PathVariable(“userId”) Integer userId, HttpServletResponse response) throws Exception{
        response.setContentType(”application/json”);
        response.getWriter().println(”{\”no\”:”+userId+“,\”userName\”:\”user”+userId+“\”,\”age\”:null}”);
    }

}

package edu.mvcdemo.controller;

import javax.servlet.http.HttpServletResponse;
import org.springframework.context.annotation.Scope;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import edu.mvcdemo.model.User;

/**
 * @编写人： yh.zeng
 * @编写时间：2017-8-7 下午10:12:26
 * @文件描述: Controller返回JSON数据的demo
 */
@Controller
@Scope(value="singleton") //只实例化一个bean对象（即每次请求都使用同一个bean对象），默认是singleton
public class ReturnJsonController {

    /**
     * 方式一：使用@ResponseBody标注
     * @param userId
     * @return
     */
    @ResponseBody
    @RequestMapping(value="/jsontype/view1/users/{userId}", method=RequestMethod.GET)
    public User getUserInJson(@PathVariable("userId") Integer userId){
        User user = new User();
        user.setNo(userId);
        user.setUserName("user"+userId);
        return user;
    }

    /**
     * 方式二：使用ResponseEntity
     * @param userId
     * @return
     */
    @RequestMapping(value="/jsontype/view2/users/{userId}", method=RequestMethod.GET)
    public ResponseEntity getUserInJson2(@PathVariable("userId") Integer userId){
        User user = new User();
        user.setNo(userId);
        user.setUserName("user"+userId);
        return new ResponseEntity(user, HttpStatus.OK);
    }

    /**
     * 方式三：使用HttpServletResponse对象返回JSON数据
     * @param userId
     * @param response
     * @throws Exception
     */
    @RequestMapping(value="/jsontype/view3/users/{userId}", method=RequestMethod.GET)
    public void getUserInJson3(@PathVariable("userId") Integer userId, HttpServletResponse response) throws Exception{
        response.setContentType("application/json");
        response.getWriter().println("{\"no\":"+userId+",\"userName\":\"user"+userId+"\",\"age\":null}");
    }

}

项目demo：https://github.com/zengyh/MavenSpringMvcDemo.git