最近上班太忙，晚上抽空整理一下ajax请求中，后台返回json字符串和json数组的场景，以及前台的处理示例。
直接看代码。
json字符串的后台响应
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 { // 构造json对象 String resStr = "{" + "name:" + "\"zhangsan\"," + "id:" + "\"id001\"" + "}"; // 输出json对象到前台 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数组的后台响应
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 { // 构造json对象 String resStr1 = "{" + "name:" + "\"zhangsan\"," + "id:" + "\"id001\"" + "}"; String resStr2 = "{" + "name:" + "\"lisi\"," + "id:" + "\"id002\"" + "}"; String resStr3 = "{" + "name:" + "\"wangwu\"," + "id:" + "\"id003\"" + "}"; // 构造json数组 String jsonArr = "[" + resStr1 + "," + resStr2 + "," + resStr3 + "]"; // 输出json数组到前台 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); } }
前台页面
<%@ 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字符串处理方法 function jsonStr() { var xhr = new XMLHttpRequest(); xhr.open("get", "jsonStr"); xhr.onreadystatechange = function(data) { if (xhr.readyState == 4 && xhr.status == 200) { // 将json字符串转换为json对象 var obj = eval("(" + data.target.responseText + ")"); document.getElementById("username").value = obj.name; document.getElementById("id").value = obj.id; } }; xhr.send(null); } // json数组处理方法 function jsonArr() { var xhr = new XMLHttpRequest(); xhr.open("get", "jsonArr"); xhr.onreadystatechange = function(data) { if (xhr.readyState == 4 && xhr.status == 200) { // 将json字符串转换为json数组 var obj = eval("(" + data.target.responseText + ")"); // 创建代码片段，用于存放表格行 var oFragment = document.createDocumentFragment(); // 根据json数组长度，产生行数据 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); } // 将行数据添加在表格的tBody部分 document.getElementById("tb").appendChild(oFragment); } }; xhr.send(null); } </script> </html>
页面效果图
点击 JsonStr 和 JsonArr 按钮后的效果
好了，整理完毕，示例仅供学习。
对了，有一点疑惑，之前回调函数中，获取响应数据的时候，都是直接通过data.responseText 来获取的，今天的代码中必须使用data.target.responseText，不知道为什么？有知道的朋友烦请告知一声，非常感谢。
以上这篇ajax响应json字符串和json数组的实例(详解)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持脚本之家。