JSON.parseObject 是将Json字符串转化为相应的对象；

JSON.toJSONString 是将对象转化为Json字符串

两者主要用于前后台的数据传输过程中

使用前需要先导入该包：

<dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.62</version>
</dependency>

一、JSON.parseObject

将JSON字符串转为Bean对象

Java 对象 Student

@Data
@Accessors(chain = true)
public class Student {private String name;private int score;
}

将JSON字符串转为该对象

public class Main {public static void main(String[] args) {String jsonStudent = "{name:'yolo',score:90}";Student student = JSON.parseObject(jsonStudent, Student.class);System.out.println(student);}
}

二、JSON.toJSONString

是将对象转化为Json字符串

public class Main {public static void main(String[] args) {Student student = new Student().setName("yolo").setScore(98);String s = JSON.toJSONString(student);System.out.println(s);}
}

三、JSON.parseObject 的其他几种使用

示例1：str = “{“name”:“Yolo”,“Address”:“Beijing”}”;

public class Main {public static void main(String[] args) {String str = "{\"name\":\"Yolo\",\"Address\":\"Beijing\"}";JSONObject jsonObject = JSON.parseObject(str);System.out.println(jsonObject.toString());System.out.println(jsonObject.getString("name"));System.out.println(str);}
}

示例2：str2 = “{“name”:“Yolo”,“Address”:“Beijing”, “data”:{“id”: 123}}”

public class Main {public static void main(String[] args) {String str2 = "{\"name\":\"Yolo\",\"Address\":\"Beijing\", \"data\":{\"id\": 123}}";JSONObject jsonObject2 = JSON.parseObject(str2);System.out.println(jsonObject2.getString("data"));System.out.println(JSON.parseObject(jsonObject2.getString("data")).getString("id"));}
}

示例3：str3 = “{“name”:“Yolo”,“Address”:“Beijing”, “data”:[{“id”: 123},{“id”: 345}]}”;

public class Main {public static void main(String[] args) {String str3 = "{\"name\":\"Yolo\",\"Address\":\"Beijing\", \"data\":[{\"id\": 123},{\"id\": 345}]}";JSONObject jsonObject3 = JSON.parseObject(str3);System.out.println(jsonObject3.toString());System.out.println(jsonObject3.toJSONString());System.out.println("data " + jsonObject3.getString("data"));JSONArray data = JSON.parseArray(jsonObject3.getString("data"));for (Object d: data) {System.out.println(d);System.out.println(JSON.parseObject(d.toString()).getString("id"));System.out.println(JSON.parseObject(String.valueOf(d)).getString("id"));}}
}