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。
