2018.7.27 Json与Java相互转换

Json.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>    
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery-3.2.1.js"></script>
<script type="text/javascript" >
	$(function(){
		$.post("JsonServlet",{method:"entityJson"},function(msg){
			//console.log(msg);//调试
			//接收过来是String   要转成对象才能点里面的属性
			var json = JSON.parse(msg);	//字符串---->对象
			$("#Uname").val(json.uname);//给文本框中value赋值
			$("#num").val(json.uid);//给文本框中value赋值
			$("#addr").html(json.address);
		});
		
		
		$.post("JsonServlet",{method:"jsonList"},function(pList){
			//console.log(msg);//调试
			//接收过来是String   要转成对象才能点里面的属性
			var pObj = $.parseJSON(pList);//字符串----->数组对象
			$.each(pObj,function(i,p){
				var li = "<li>"+p.uid+"</li>"+"<li>"+p.uname+"</li>"+"<li>"+p.address+"</li>"+"<br/>";
				$("#myUl").append(li);
			});	
		});
		
		
		$("#btn").click(function(){
			var url = "JsonServlet";
			var data ={"method":"jsonMap"};
			$.post(url,data,function(pMap){
				var personMap = $.parseJSON(pMap);//json集合字符串转json对象
				$.each(personMap,function(key,value){
					$.each(value,function(i,person){
						var li = "<li>"+person.uid+person.uname+person.address+"</li>";
						$("#myMap").append(li);
					});
				});
			});
		});
	

		
	})
</script>
</head>
<body>
<h3>Java实体(字符串)转JSON对象  JSON.parse(msg);</h3>
	ID:<input type="text" id="num"><br/>
	Name:<input type="text" id="Uname" ><br/>
	Address:<span id="addr" ></span>
	
<hr>
<h3>Java集合转JSON数组对象  $.parseJSON(pList)</h3>
	<ul id="myUl">
	</ul>
	
	
<hr>

<h3>Map集合转JSON对象</h3>	
<button id='btn'>获取Map集合数据</button>
<ul id="myMap">

</ul>
</body>
</html>

JsonServlet

package servlet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.collections.map.HashedMap;

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


@WebServlet("/JsonServlet")
public class JsonServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String method = request.getParameter("method");
		if(method.equals("entityJson")) {
			//设置编码格式  不然会显示乱码
			response.setContentType("text/html;charset=utf-8");
			Person p = new Person(1001, "张三", "男", "广西");
			// 1. java实体转json对象
			JSONObject jsonObj = JSONObject.fromObject(p);
			//发送数据    字符串形式
			response.getWriter().println(jsonObj);
			System.out.println(jsonObj);
			
		}else if(method.equals("jsonList")){
			//设置编码格式  不然会显示乱码
			response.setContentType("text/html;charset=utf-8");
			List<Person> pList = new ArrayList<Person>();
			Person p1 = new Person(1001, "张三", "男", "广西");
			Person p2 = new Person(1002, "李四", "女", "广东");
			Person p3 = new Person(1003, "王五", "男", "四川");
			pList.add(p1);
			pList.add(p2);
			pList.add(p3);
			JSONArray jsonObject =  JSONArray.fromObject(pList);
			System.out.println("集合长度是"+jsonObject.size());
			response.getWriter().println(jsonObject);
		}else if(method.equals("jsonMap")){
			//设置编码格式  不然会显示乱码
			response.setContentType("text/html;charset=utf-8");
			Map<String,Person> mp = new HashMap<String,Person>();
			mp.put("管理员", new Person(1001, "张三", "男", "广西"));
			mp.put("游客", new Person(1002, "张四", "男", "广西"));
			JSONArray jsonMap =  JSONArray.fromObject(mp);
			//发送数据
			response.getWriter().println(jsonMap);
		}
	}

}

原文地址:https://www.cnblogs.com/qichunlin/p/9379097.html