json比较可读，通过键值对返回。实现通常有两种方式:一种是自己来构造，也就是用一个对象存储数据，在最后输出时将其json字符串化；第二种是使用 @RestController 注解实现json数据返回。

第一种 

导入依赖坐标：

        <dependency>
<!--            json--><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-json</artifactId></dependency>

实体类：

public class Pet {private Long id;private String name;private int age;private String color;private String description;public Pet(Long id, String name, int age, String color, String description) {this.id = id;this.name = name;this.age = age;this.color = color;this.description = description;}public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getColor() {return color;}public void setColor(String color) {this.color = color;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}
}

创建一个Controller进行测试：

@RestController
@RequestMapping("/test_json")
public class TestJson {@Autowiredpublic Testjson testjson;@RequestMapping("/pet")public Pet getPet(){return new Pet(1L,"团团",2,"black","a cut panda");}@RequestMapping("/petList")public List<Pet> getPetList(){List<Pet> pets = new ArrayList<>();pets.add(new Pet(2L,"小狗",3,"write","a dog"));pets.add(new Pet(1L,"小猪",2,"pink","a pig"));return pets;}}

完成。

第二种 

这里使用第三方代替实现，此方法比较粗糙不推荐使用，例如选择 alibaba 开源的 faskjson。依赖配置：

            <groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>2.0.25</version>

 测试提供的实体类：

package org.example.pojo;public class User {private String name;private String password;public User(String name, String password) {this.name = name;this.password = password;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

测试类：

package org.example.service;import com.alibaba.fastjson.JSON;
import org.example.pojo.User;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;import java.util.ArrayList;
import java.util.List;
@Component
public class Testjson {public String objectToJson(){//单个Java 对象User user = new User("tfboys","2333");String userJsonStr = JSON.toJSONString(user);System.out.println("java类转json字符串为："+userJsonStr);//多个java 对象User user1 = new User("gameboy","2334");User user2 = new User("steatboy","456789");List<User> users = new ArrayList<>();users.add(user1);users.add(user2);String ListUserJson = JSON.toJSONString(users);System.out.println("List<Object> 转 json字符串是:"+ListUserJson);jsonToObject();return ListUserJson.toString();}public void jsonToObject(){String jsonStr1 = "{'password':'123456','name':'dmeget'}";User user = JSON.parseObject(jsonStr1, User.class);System.out.println("json字符串转简单java对象："+user.toString());}
}

这里使用了两个比较重要的方法：一个是把对象json化的toJsonString方法，另一个是把json对象化的parseObject。