JSONObject与JSONArray的使用区别

1.JSON

1. 创建一个JSONObject对象：

package com.yunos.tv.video.resource.controller.web;

import java.util.ArrayList;
import java.util.HashMap;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class Test {

    public static void main(String[] args) {
        //JsonObject和JsonArray区别就是JsonObject是对象形式，JsonArray是数组形式
        //创建JsonObject第一种方法
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("UserName", "ZHULI");
        jsonObject.put("age", "30");
        jsonObject.put("workIn", "ALI");
        System.out.println("jsonObject1：" + jsonObject);

        //创建JsonObject第二种方法
        HashMap<String, String> hashMap = new HashMap<String, String>();
        hashMap.put("UserName", "ZHULI");
        hashMap.put("age", "30");
        hashMap.put("workIn", "ALI");
        System.out.println("jsonObject2：" + JSONObject.fromObject(hashMap));

        //创建一个JsonArray方法1
        JSONArray jsonArray = new JSONArray();
        jsonArray.add(0, "ZHULI");
        jsonArray.add(1, "30");
        jsonArray.add(2, "ALI");
        System.out.println("jsonArray1：" + jsonArray);

        //创建JsonArray方法2
        ArrayList<String> arrayList = new ArrayList<String>();
        arrayList.add("ZHULI");
        arrayList.add("30");
        arrayList.add("ALI");
        System.out.println("jsonArray2：" + JSONArray.fromObject(arrayList));

        //如果JSONArray解析一个HashMap，则会将整个对象的放进一个数组的值中
        System.out.println("jsonArray FROM HASHMAP：" + JSONArray.fromObject(hashMap));

        //组装一个复杂的JSONArray
        JSONObject jsonObject2 = new JSONObject();
        jsonObject2.put("UserName", "ZHULI");
        jsonObject2.put("age", "30");
        jsonObject2.put("workIn", "ALI");
        jsonObject2.element("Array", arrayList);
        System.out.println("jsonObject2：" + jsonObject2);

    }
}

结果：

jsonObject1：{"UserName":"ZHULI","age":"30","workIn":"ALI"}
jsonObject2：{"workIn":"ALI","age":"30","UserName":"ZHULI"}
jsonArray1：["ZHULI","30","ALI"]
jsonArray2：["ZHULI","30","ALI"]
jsonArray FROM HASHMAP：[{"workIn":"ALI","age":"30","UserName":"ZHULI"}]
jsonObject2：{"UserName":"ZHULI","age":"30","workIn":"ALI","Array":["ZHULI","30","ALI"]}

解析JSON字符串：

package com.yunos.tv.video.resource.controller.web;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class Test {

    public static void main(String[] args) {
        String jsonString = "{\"UserName\":\"ZHULI\",\"age\":\"30\",\"workIn\":\"ALI\",\"Array\":[\"ZHULI\",\"30\",\"ALI\"]}";
        //将Json字符串转为java对象
        JSONObject obj = JSONObject.fromObject(jsonString);
        //获取Object中的UserName
        if (obj.has("UserName")) {
            System.out.println("UserName:" + obj.getString("UserName"));
        }
        //获取ArrayObject
        if (obj.has("Array")) {
            JSONArray transitListArray = obj.getJSONArray("Array");
            for (int i = 0; i < transitListArray.size(); i++) {
                System.out.print("Array:" + transitListArray.getString(i) + " ");
            }
        }
    }
}

返回：

UserName:ZHULI
Array:ZHULI Array:30 Array:ALI 

optString的简单介绍：

.getString(String name)与optString(String name)，功能一样，返回object中某个字段。只是当无返回值时，getString(String name)抛出错误，optString(String name)返回空值

jsonArray.opt的简单介绍：
在遍历某个jsonArray对象的饿时候，返回某个对应的JSONObject对象