Java实现Json字符串与Object对象相互转换的方式总结

public class User {
  private String name;
  private Integer age;
  private String location;
  public User() {
  }
  public User(String name) {
    this.name = name;
  }
  public User(String name, Integer age) {
    this.name = name;
    this.age = age;
  }
  public User(String name, Integer age, String location) {
    this.name = name;
    this.age = age;
    this.location = location;
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public Integer getAge() {
    return age;
  }
  public void setAge(Integer age) {
    this.age = age;
  }
  public String getLocation() {
    return location;
  }
  public void setLocation(String location) {
    this.location = location;
  }
  @Override
  public String toString() {
    return "User{" +
        "name='" + name + '\'' +
        ", age=" + age +
        ", location='" + location + '\'' +
        '}';
  }
}

  <dependency>
   <groupId>net.sf.json-lib</groupId>
   <artifactId>json-lib</artifactId>
   <version>2.4</version>
   <classifier>jdk15</classifier>
  </dependency>

import net.sf.json.JSONObject;
public class JsonLibDemo {
  public static void main(String[] args) {
    //创建测试object
    User user = new User("李宁",24,"北京");
    System.out.println(user);
    //转成json字符串
    JSONObject jsonObject = JSONObject.fromObject(user);
    String json = jsonObject.toString();
    System.out.println(json);
    //json字符串转成对象
    JSONObject jsonObject1 = JSONObject.fromObject(json);
    User user1 = (User) JSONObject.toBean(jsonObject1,User.class);
    System.out.println(user1);
  }
}

  <dependency>
   <groupId>org.json</groupId>
   <artifactId>json</artifactId>
   <version>20170516</version>
  </dependency>

import org.json.JSONObject;
public class OrgJsonDemo {
  public static void main(String[] args) {
    //创建测试object
    User user = new User("李宁",24,"北京");
    System.out.println(user);
    //转成json字符串
    String json = new JSONObject(user).toString();
    System.out.println(json);
    //json字符串转成对象
    JSONObject jsonObject = new JSONObject(json);
    String name = jsonObject.getString("name");
    Integer age = jsonObject.getInt("age");
    String location = jsonObject.getString("location");
    User user1 = new User(name,age,location);
    System.out.println(user1);
  }
}

  <dependency>
   <groupId>com.fasterxml.jackson.core</groupId>
   <artifactId>jackson-databind</artifactId>
   <version>2.9.0</version>
  </dependency>

import com.fasterxml.jackson.databind.ObjectMapper;
public class JacksonDemo {
  public static void main(String[] args) {
    //创建测试object
    User user = new User("李宁",24,"北京");
    System.out.println(user);
    //转成json字符串
    ObjectMapper mapper = new ObjectMapper();
    try {
      String json = mapper.writeValueAsString(user);
      System.out.println(json);
      //json字符串转成对象
      User user1 = mapper.readValue(json,User.class);
      System.out.println(user1);
    } catch (java.io.IOException e) {
      e.printStackTrace();
    }
  }
}

  <dependency>
   <groupId>com.google.code.gson</groupId>
   <artifactId>gson</artifactId>
   <version>2.8.1</version>
  </dependency>

import com.google.gson.Gson;
public class GsonDemo {
  public static void main(String[] args) {
    //创建测试object
    User user = new User("李宁",24,"北京");
    System.out.println(user);
    //转成json字符串
    Gson gson = new Gson();
    String json = gson.toJson(user);
    System.out.println(json);
    //json字符串转成对象
    User user1 = gson.fromJson(json,User.class);
    System.out.println(user1);
  }
}

  <dependency>
   <groupId>com.alibaba</groupId>
   <artifactId>fastjson</artifactId>
   <version>1.2.37</version>
  </dependency>

import com.alibaba.fastjson.JSON;
public class FastJsonDemo {
  public static void main(String[] args) {
    //创建测试object
    User user = new User("李宁",24,"北京");
    System.out.println(user);
    //转成json字符串
    String json = JSON.toJSON(user).toString();
    System.out.println(json);
    //json字符串转成对象
    User user1 = JSON.parseObject(json,User.class);
    System.out.println(user1);
  }
}