fastjson的基本用法，fastjson对日期的处理

Posted 2020-09-13

fastjson应该是java中对json处理性能最好的jar包了，只需要引入fastjson一个jar包即可，无需其他依赖！

下面是fastjson的一些常用的用法！

javabean 转 JSONObject:  JSON.toJSON(javabean);　　//需要强转化

javabean的集合 转 JSONArray:  JSON.toJSON(javabean的集合);　　//需要强转化

JSONObject 转 javabean: JSON.toJavaObject(json,Class);

JSONArray 转　javabean的集合：json.toJavaObject(jsonArray,List.class)　　//

package com.loger.fastjson;

import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;

public class MyTest {
    public static void main(String[] args) throws ParseException {
        User user = new User("007","陈乐");
        List<User> list = new ArrayList<>();
        list.add(user);
        list.add(user);
        JSONObject o = new JSONObject();
        o = (JSONObject) JSON.toJSON(user);
        System.out.println("测试javabean变JSONObject:\\n"+o);
        System.out.println("--------------------");
        User user2 = JSON.toJavaObject(o, User.class);
        System.out.println("测试JSONObject变javabean:\\n"+user2);
        System.out.println("--------------------");
        JSONArray jsonArray = (JSONArray) JSON.toJSON(list);
        System.out.println("测试javalist变jsonarray:\\n"+jsonArray);
        System.out.println("-------------");
        List<User> list2 = JSON.toJavaObject(jsonArray, List.class);
        System.out.println("jsonarray变javabean集合"+list2.toString());
        System.out.println("----------------");
    }
}

运行结果：

 

fastjson对日期的处理：

javabean:

package com.loger.fastjson;

import java.util.Date;

import com.alibaba.fastjson.annotation.JSONField;

public class UserWithDate {
    
    private String name;
    @JSONField(format="yyyy-mm-dd")
    private Date date;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getDate() {
        return date;
    }
    public void setDate(Date date) {
        this.date = date;
    }
    public UserWithDate(String name, Date date) {
        super();
        this.name = name;
        this.date = date;
    }
    public UserWithDate() {
        super();
    }
    @Override
    public String toString() {
        return "UserWithDate [name=" + name + ", date=" + date + "]";
    }
    
    
}

Main.java

package com.loger.fastjson;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;

public class TestForDate {
    
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd");
        Date date = sdf.parse("1995-09-01");
        UserWithDate user = new UserWithDate("陈乐",date);
        JSONObject o = (JSONObject) JSON.toJSON(user);
        System.out.println(o);
        System.out.println("------------------");
        UserWithDate user2 = new UserWithDate();
        user2 = JSON.toJavaObject(o, UserWithDate.class);
        System.out.println(user2);
    }
    
}

结果：