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ajax響應(yīng)json字符串和json數(shù)組的實(shí)例(詳解)

更新時(shí)間：2017年02月17日 08:56:50 投稿：jingxian

下面小編就為大家?guī)硪黄猘jax響應(yīng)json字符串和json數(shù)組的實(shí)例(詳解)。小編覺得挺不錯(cuò)的，現(xiàn)在就分享給大家，也給大家做個(gè)參考。一起跟隨小編過來看看吧

最近上班太忙，晚上抽空整理一下ajax請(qǐng)求中，后臺(tái)返回json字符串和json數(shù)組的場(chǎng)景，以及前臺(tái)的處理示例。

直接看代碼。

json字符串的后臺(tái)響應(yīng)

package com.ajax;

import java.io.IOException;
import java.io.PrintWriter;

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

@WebServlet("/jsonStr")
public class JsonStr extends HttpServlet {

 /**
 * 
 */
 private static final long serialVersionUID = 1L;

 @Override
 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 // 構(gòu)造json對(duì)象
 String resStr = "{" + "name:" + "\"zhangsan\"," + "id:" + "\"id001\"" + "}";
 
 // 輸出json對(duì)象到前臺(tái)
 PrintWriter out = resp.getWriter();
 out.write(resStr);
 out.flush();
 out.close();
 }

 @Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 doGet(req, resp);
 }
}

json數(shù)組的后臺(tái)響應(yīng)

package com.ajax;

import java.io.IOException;
import java.io.PrintWriter;

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

@WebServlet("/jsonArr")
public class JsonArr extends HttpServlet {

 /**
 * 
 */
 private static final long serialVersionUID = 1L;

 @Override
 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 // 構(gòu)造json對(duì)象
 String resStr1 = "{" + "name:" + "\"zhangsan\"," + "id:" + "\"id001\"" + "}";
 String resStr2 = "{" + "name:" + "\"lisi\"," + "id:" + "\"id002\"" + "}";
 String resStr3 = "{" + "name:" + "\"wangwu\"," + "id:" + "\"id003\"" + "}";
 
 // 構(gòu)造json數(shù)組
 String jsonArr = "[" + resStr1 + "," + resStr2 + "," + resStr3 + "]";
 
 // 輸出json數(shù)組到前臺(tái)
 PrintWriter out = resp.getWriter();
 out.write(jsonArr);
 out.flush();
 out.close();
 }

 @Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
  throws ServletException, IOException {
 doGet(req, resp);
 }
}

前臺(tái)頁面

<%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Json</title>
</head>
<body>
 <br><br>
 <input type="button" value="JsonStr" onclick="jsonStr()" />
 <br><br>
 <table>
 <tr>
  <td>username</td>
  <td><input id="username"></td>
 </tr>
 <tr>
  <td>id</td>
  <td><input id="id"></td>
 </tr>
 </table>
 <br><br><br>
 <input type="button" value="JsonArr" onclick="jsonArr()" />
 <br><br>
 <table border="1" bordercolor="red">
 <caption>Json Array</caption>
 <thead>
  <tr>
  <th>Username</th>
  <th>Id</th>
  </tr>
 </thead>
 <tbody id="tb">
 </tbody>
 </table>
</body>
<script type="text/javascript">
 // json字符串處理方法
 function jsonStr() {
 var xhr = new XMLHttpRequest();
 xhr.open("get", "jsonStr");
 xhr.onreadystatechange = function(data) {
  if (xhr.readyState == 4 && xhr.status == 200) {
  // 將json字符串轉(zhuǎn)換為json對(duì)象
  var obj = eval("(" + data.target.responseText + ")");
  document.getElementById("username").value = obj.name;
  document.getElementById("id").value = obj.id;
  }
 };
 xhr.send(null);
 }
 
 // json數(shù)組處理方法
 function jsonArr() {
 var xhr = new XMLHttpRequest();
 xhr.open("get", "jsonArr");
 xhr.onreadystatechange = function(data) {
  if (xhr.readyState == 4 && xhr.status == 200) {
  // 將json字符串轉(zhuǎn)換為json數(shù)組
  var obj = eval("(" + data.target.responseText + ")");
  
  // 創(chuàng)建代碼片段，用于存放表格行
  var oFragment = document.createDocumentFragment();
  
  // 根據(jù)json數(shù)組長度，產(chǎn)生行數(shù)據(jù)
  for (var i=0; i<obj.length; i++) {
   var trObj = document.createElement("tr");
   trObj.innerHTML = "<td>" + obj[i].name + "</td><td>" + obj[i].id + "</td>";
   oFragment.appendChild(trObj);
  }
  
  // 將行數(shù)據(jù)添加在表格的tBody部分
  document.getElementById("tb").appendChild(oFragment);
  }
 };
 xhr.send(null);
 }
</script>
</html>

頁面效果圖

點(diǎn)擊 JsonStr 和 JsonArr 按鈕后的效果

好了，整理完畢，示例僅供學(xué)習(xí)。

對(duì)了，有一點(diǎn)疑惑，之前回調(diào)函數(shù)中，獲取響應(yīng)數(shù)據(jù)的時(shí)候，都是直接通過data.responseText 來獲取的，今天的代碼中必須使用data.target.responseText，不知道為什么？有知道的朋友煩請(qǐng)告知一聲，非常感謝。

以上這篇ajax響應(yīng)json字符串和json數(shù)組的實(shí)例(詳解)就是小編分享給大家的全部內(nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持腳本之家。

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