JSONArray和JSONObject的简单使用-白红宇

JSONArray和JSONObject的简单使用

阅读量：5089 次

发布时间：2019-06-13

本文共 5593 字，大约阅读时间需要 18 分钟。

一、为什么要使用JSONArray和JSONObject

1、后台 --》前台能够把java对象和集合转化成json字符串格式，这样在前台的ajax方法中能够直接转化成json对象使用，从后台向前台传值

2、前台 --》使用JSON.stringify(mdses)方法把js对象，数组。转化成json字符串，后台使用JSONArray或JSONObject 转化成 java对象或集合

有助于前端參数传递到后端。和后端取值y

3、json如今以成为大多传输数据的载体

二、后台解析前台ajax提交数据,使用较少一般都把list 或map转化为json形式的字符串传值到前台的ajax中：

//依据接收的json字符串来解析字符串中所包括的数据和数据对象	@Test	public void parsJsonFromFront(){		//接收到的json		String result = "[{\"username\": \"your name\", \"user_json\": {\"username\": \"your name\", \"nickname\": \"your nickname\"}}]";	 	//依据字符串陈		//依据字符串生成JSON对象		//假设是数组的形式 就使用 JSONArray.fromObject(result) 转化为JSONArray 对象		//假设是json对象  就是使用JSONObject.fromObject(result) 转化为JSONObject 对象		JSONArray resultArray = JSONArray.fromObject(result);		JSONObject jsonObject = resultArray.getJSONObject(0);		JSONObject user_json = jsonObject.getJSONObject("user_json");		//依据key值取值		String username = user_json.getString("username");		String nickname = user_json.getString("nickname");		System.out.println("username =" + username  + ":" + "nickname = " + nickname);		//console ：  username =your name:nickname = your nickname	}

三、后台转化list 或map转化为json形式的字符串传值到前台的ajax中

user bean

public class User {	private String name;	private Adress adress;	private List
     
       students;	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public Adress getAdress() {		return adress;	}	public void setAdress(Adress adress) {		this.adress = adress;	}	public List
      
        getStudents() {		return students;	}	public void setStudents(List
       
         students) {		this.students = students;	}	public User(String name, Adress adress, List
        
          students) {		super();		this.name = name;		this.adress = adress;		this.students = students;	}	public User() {		super();	}	}

public class Adress {	private String streetName;	private String district;	public String getStreetName() {		return streetName;	}	public void setStreetName(String streetName) {		this.streetName = streetName;	}	public String getDistrict() {		return district;	}	public void setDistrict(String district) {		this.district = district;	}	public Adress(String streetName, String district) {		super();		this.streetName = streetName;		this.district = district;	}	public Adress() {		super();		// TODO Auto-generated constructor stub	}	}

1）bean to json

@Test	public void beanToJson(){		List list = new ArrayList();		list.add( "xiaowang" );		list.add( "xiaohua" );		Adress adress =  new Adress("streetName", "district");		JSONObject jsonObject =  JSONObject.fromObject(new User("name", adress, list));		System.out.println(jsonObject.toString());		//console ：{"adress":{"district":"district","streetName":"streetName"},"name":"name","students":["xiaowang","xiaohua"]}	}

2）

@Test	public void list2Json(){		List list = new ArrayList();		list.add( "first" );		list.add( "second" );		JSONArray  jsonArray = JSONArray.fromObject(list);		System.out.println(jsonArray.toString());	}		public Map getMap(){		 //声明一个Hash对象并加入数据		 Map params =  new HashMap();			params.put("username", "username");		params.put("user_json", "user");		return params;	}	@Test	public void map2Json(){		Map map = getMap();		Map map1 = getMap();		List list = new ArrayList();		list.add(map);		list.add(map1);		JSONArray jsonArray = JSONArray.fromObject(list);		System.out.println("jsonArray--->" + jsonArray.toString());		JSONArray jsonArray1 = JSONArray.fromObject(map);		System.out.println("jsonArray1--->" + jsonArray1.toString());	}

完整：

public class SimpleExample {		@Test	public void list2Json(){		List list = new ArrayList();		list.add( "first" );		list.add( "second" );		JSONArray  jsonArray = JSONArray.fromObject(list);		System.out.println(jsonArray.toString());	}		public Map getMap(){		 //声明一个Hash对象并加入数据		 Map params =  new HashMap();			params.put("username", "username");		params.put("user_json", "user");		return params;	}	@Test	public void map2Json(){		Map map = getMap();		Map map1 = getMap();		List list = new ArrayList();		list.add(map);		list.add(map1);		JSONArray jsonArray = JSONArray.fromObject(list);		System.out.println("jsonArray--->" + jsonArray.toString());		JSONArray jsonArray1 = JSONArray.fromObject(map);		System.out.println("jsonArray1--->" + jsonArray1.toString());	}	//依据接收的json字符串来解析字符串中所包括的数据和数据对象	@Test	public void parsJsonFromFront(){		//接收到的json		String result = "[{\"username\": \"your name\", \"user_json\": {\"username\": \"your name\", \"nickname\": \"your nickname\"}}]";	 	//依据字符串陈		//依据字符串生成JSON对象		//假设是数组的形式 就使用 JSONArray.fromObject(result) 转化为JSONArray 对象		//假设是json对象  就是使用JSONObject.fromObject(result) 转化为JSONObject 对象		JSONArray resultArray = JSONArray.fromObject(result);		JSONObject jsonObject = resultArray.getJSONObject(0);		JSONObject user_json = jsonObject.getJSONObject("user_json");		//依据key值取值		String username = user_json.getString("username");		String nickname = user_json.getString("nickname");		System.out.println("username =" + username  + ":" + "nickname = " + nickname);		//console ：  username =your name:nickname = your nickname	}		@Test	public void beanToJson(){		List list = new ArrayList();		list.add( "xiaowang" );		list.add( "xiaohua" );		Adress adress =  new Adress("streetName", "district");		JSONObject jsonObject =  JSONObject.fromObject(new User("name", adress, list));		System.out.println(jsonObject.toString());		//console ：{"adress":{"district":"district","streetName":"streetName"},"name":"name","students":["xiaowang","xiaohua"]}	}	}

相关依赖jar下载：http://download.csdn.net/detail/hao007cn/8995465

转载于:https://www.cnblogs.com/yfceshi/p/7010757.html

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