java转换json的方式

时间 2019-11-12

标签 java 转换 json 方式栏目 Java 繁體版

原文原文链接

1.引言javascript

2.对象json转换一般经常使用Map参数形式，优势是1.属性有key,js前端能够清晰从后台key解析出来 2.MAP参数方便添加其余集合如List即包含可能其余集合的信息,承载的信息能够是多种组合方式.。
html

如 Map map=new HashMap(); 前端

map.put("id",1); java

map.name("name"，"张三"); jquery

String result=JSONObject.fromObject(map1).toString();
ajax

输出结果是 json

{"id":1,"name":"张三"} async

前台页面取值
post

$.ajax({
                   cache:false,
                   type:'post',
                   async:false,
                   height:350,
                    url:'<%=path%>/jsonServlet',
                    dataType: 'json',
                    timeout: 1000,
                   data:{"txtName":txtName},
                    success: function(data){
                       var obj = eval(data);
                       alert(obj.id); //这里取的是键id
                       $.each(obj,function(i,n){ //循坏开始
                           alert(n);
                          });


                    },
                    error: function(XMLHttpRequest, textStatus, errorThrown){
                       //alert(XMLHttpRequest.status);
                       return false;
                    }
               });

});
ui

js前台取值以下

下面咱们在往Map添加一个List,下面模拟输入模糊查询张

    request.setCharacterEncoding("utf-8");
    response.setContentType("text/json;charset=utf-8");
    response.setCharacterEncoding("utf-8");

String txtName = request.getParameter("txtName"); // 获取查询姓名

String personList[] = { "张三", "张一", "张二", "张三", "张四", "张五" }; // 人员信息列表

     List list = new ArrayList();
   Map map = new HashMap();
   int coutnNum = 0;
   if (!txtName.isEmpty()) {
           txtName = txtName.substring(0, 1);
           map.put("id", ++coutnNum);
           for (String person : personList) {
               if (txtName.equals(person.substring(0, 1))) {
                   list.add(person);

               }

           }
           map.put("list", list);

     }

JSONObject json = JSONObject.fromObject(map);
String result = json.toString();

输出结果是{"id":1,"list":["张三","张一","张二","张三","张四","张五"]}

前台页面取值的方式取list的

var obj = eval(data);
var list=obj.list;
$.each(list,function(i,n){ //循坏开始
alert(n);
});

3.完整列子以下

前台页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <meta content="text/html; charset=utf-8" http-equiv=Content-Type>
   <meta http-equiv="pragma" content="no-cache">
   <meta http-equiv="cache-control" content="no-cache">
   <meta http-equiv="expires" content="0">
   <script type="text/javascript" src="common/js/jquery-1.4.2.min.js"></script>
   <script type="text/javascript">
        $(document).ready(function(){
             $("#frm1").click(function (){
                var txtName=$("#txtName").val();
                //txtName=encodeURI(encodeURI(txtName));
               // alert(txtName);
                 $.ajax({
                   cache:false,
                   type:'post',
                   async:false,
                   height:350,
                    url:'<%=path%>/jsonServlet',
                    dataType: 'json',
                    timeout: 1000,
                   data:{"txtName":txtName},
                    success: function(data){
                       var obj = eval(data);
                       var list=obj.list;
                       $.each(list,function(i,n){ //循坏开始
                           alert(n);
                          });


                    },
                    error: function(XMLHttpRequest, textStatus, errorThrown){
                       //alert(XMLHttpRequest.status);
                       return false;
                    }
               });

              });
       });

   </script>

</head>

<body>
      <input type="text" id="txtName" name="txtName"/>
      <input type="button" id="frm1" value="提交"/>
      <textarea rows="10" cols="50">

      </textarea>
</body>
</html>

4.后台java

package com.test;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import net.sf.json.JSONArray;import net.sf.json.JSONObject;public class JsonServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setContentType("text/json;charset=utf-8"); response.setCharacterEncoding("utf-8"); String txtName = request.getParameter("txtName"); // 获取查询姓名 String personList[] = { "张三", "张一", "张二", "张三", "张四", "张五" }; // 人员信息列表 JSONArray jsonArray = new JSONArray(); List list = new ArrayList(); Map map = new HashMap(); int coutnNum = 0; if (!txtName.isEmpty()) { txtName = txtName.substring(0, 1); map.put("id", ++coutnNum); for (String person : personList) { if (txtName.equals(person.substring(0, 1))) { list.add(person); } } map.put("list", list); } JSONObject json = JSONObject.fromObject(map); String result = json.toString(); PrintWriter out = response.getWriter(); out.println(result); out.flush(); out.close(); } public void init() throws ServletException { // Put your code here }}