FastJSON 转换使用

`package com.yishan.json;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**

• @Author yishan
• @Date 2021/9/22 0022 10:43
• @Version 1.0
  */

public class JsonDemo {

public static void main(String[] args) {

	//JavaBean2JsonString();
	//JsonString2JavaBean();
	//JavaBean2JSONObject();
	//JsonObject2JavaBean();

}

/**
 * javaBean转jsonString---toJSONString()
 */
private static void JavaBean2JsonString() {
	List<Student> list = new ArrayList<>();
	list.add(new Student("111","yishan","24","上海",new Date()));
	list.add(new Student("111","yishan","24","上海",new Date()));
	System.out.println(list);
	//[Student(id=111, name=yishan, age=24, address=上海, birthday=Wed Sep 22 11:10:16 CST 2021), Student(id=111, name=yishan, age=24, address=上海, birthday=Wed Sep 22 11:10:16 CST 2021)]
	String s = JSON.toJSONString(list);
	System.out.println(s);
	//[{"address":"上海","age":"24","birthday":1632280216104,"id":"111","name":"yishan"},{"address":"上海","age":"24","birthday":1632280216104,"id":"111","name":"yishan"}]
}

/**
 * jsonString转javaBean---JSON.parseObject()
 * 必须要有默认的无参构造函数，否则反序列化会出错---com.alibaba.fastjson.JSONException: default constructor not found.
 */
private static void JsonString2JavaBean() {
	Student student = new Student("111", "yishan", "24", "上海", new Date());
	String jsonString = JSON.toJSONString(student);
	Student s = JSON.parseObject(jsonString, Student.class);
	System.out.println(s);
	//Student(id=111, name=yishan, age=24, address=上海, birthday=Wed Sep 22 00:00:00 CST 2021)
}

/**
 * javaBean转jsonObject---JSON.toJSON()
 */
private static void JavaBean2JSONObject() {
	Student student = new Student("111", "yishan", "24", "上海", new Date());
	//方式一：可以先转String，然后转jsonObject，之后通过key获取对应的value
	JSONObject jsonObject = JSON.parseObject(JSON.toJSONString(student));
	System.out.println(jsonObject.getString("NAME")); //yishan
	//方式二：直接转为jsonObject，通过key获取对应的value
	JSONObject json  = (JSONObject) JSON.toJSON(student);
	System.out.println(json.getString("NAME")); //yishan
}

/**
 * jsonObject转javaBean---JSON.toJavaObject()
 * 必须要有默认的无参构造函数，否则反序列化会出错
 */
private static void JsonObject2JavaBean() {
	Student student = new Student("111", "yishan", "24", "上海", new Date());
	JSONObject jsonObject  = (JSONObject) JSON.toJSON(student);
	//方式一：jsonObject转String,然后转为javaBean
	Student student1 = JSON.parseObject(jsonObject.toJSONString(), Student.class);
	System.out.println(student1);
	//方式二：jsonObject直接转javaBean
	Student student2 = JSON.toJavaObject(jsonObject, Student.class);
	System.out.println(student2);
}

}
`