Java基础98 gson插件的使用

1、要用到的包

概念：JSON是javascript对象的一种形态，是一种轻量级的数据交换格式。一般用来在Java EE后台服务和Android或者ios、HTML5之间进行通信的一种数据传递的格式。

　　   Gson是谷歌推出的一个用于生成和解析JSON数据格式的工具；

2、实例

实体类 people

 package com.shore.entity;

 /**
  * @author DSHORE/2019-4-21
  *
  */
 public class People {
     private int pid;
     private String pname;
     private int age;
     private String job;
     private double sal;

     public People() {

     }
     public People(int pid, String pname, int age, String job, double sal) {
         super();
         this.pid = pid;
         this.pname = pname;
         this.age = age;
         this.job = job;
         this.sal = sal;
     }
     public int getPid() {
         return pid;
     }
     public void setPid(int pid) {
         this.pid = pid;
     }
     public String getPname() {
         return pname;
     }
     public void setPname(String pname) {
         this.pname = pname;
     }
     public int getAge() {
         return age;
     }
     public void setAge(int age) {
         this.age = age;
     }
     public String getJob() {
         return job;
     }
     public void setJob(String job) {
         this.job = job;
     }
     public double getSal() {
         return sal;
     }
     public void setSal(double sal) {
         this.sal = sal;
     }
     @Override
     public String toString() {
         return "People [pid=" + pid + ", pname=" + pname + ", age=" + age
                 + ", job=" + job + ", sal=" + sal + "]";
     }
 }

gson 测试类

 package com.shore.test;

 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.List;

 import net.sf.json.JSONObject;

 import com.google.gson.Gson;
 import com.google.gson.reflect.TypeToken;
 import com.shore.entity.People;

 /**
  * @author DSHORE/2019-4-21
  *
  */
 public class GsonTest {
     public static void main(String[] args) {
         People p = new People();
         p.setAge(18);
         p.setPname("张三");
         p.setJob("工程师");
         p.setPid(1);
         p.setSal(10000);

         People p2 = new People();
         p2.setAge(20);
         p2.setPname("李四");
         p2.setJob("设计师");
         p2.setPid(2);
         p2.setSal(8000);

         People p3 = new People();
         p3.setAge(20);
         p3.setPname("王五");
         p3.setJob("工程师");
         p3.setPid(3);
         p3.setSal(15000);

         //1.将java对象转为json字符串
         Gson gson = new Gson();
         String json = gson.toJson(p);
         System.out.println(json); //返回值：{"pid":1,"pname":"张三","age":18,"job":"工程师","sal":10000.0}

         //2.将json字符串转为java对象
         json = "{\"age\":18,\"job\":\"工程师\",\"pid\":1,\"pname\":\"张三\",\"sal\":10000}";
         People people = gson.fromJson(json, People.class);
         System.out.println(people);//返回值：People [pid=1, pname=张三, age=18, job=工程师, sal=10000.0]
         //p2对象
         JSONObject jsonObject = JSONObject.fromObject(p2);
         System.out.println(jsonObject);//返回值：{"age":20,"job":"设计师","pid":2,"pname":"李四","sal":8000}

         //3.将一个对象集合转为json
         List<People> list = new ArrayList<People>();
         list.add(p);
         list.add(p2);
         list.add(p3);
         json=gson.toJson(list);
         System.out.println(json);//返回值：[{"pid":1,"pname":"张三","age":18,"job":"工程师","sal":10000.0},{"pid":2,"pname":"李四","age":20,"job":"设计师","sal":8000.0},{"pid":3,"pname":"王五","age":20,"job":"工程师","sal":15000.0}]

         //4.将json字符串转为带泛型集合对象
         Type listType=new TypeToken<List<People>>(){}.getType();
         List<People> list2=gson.fromJson(json,listType);
         System.out.println(list2.get(2).getPname());//返回值：王五          get(2)中的2表示：下标值
     }
 }

json插件的使用（java对象和json字符串对象之间的转换）

原创作者：DSHORE

作者主页：http://www.cnblogs.com/dshore123/

原文出自：https://www.cnblogs.com/dshore123/p/10746722.html

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