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Examples of ajax response to json strings and json arrays (graphic tutorial)

亚连Original: 2018-05-22 17:18:102032browse

Below I will bring you an example of ajax responding to json strings and json arrays. Let me share it with you now and give it as a reference for everyone.

I have been too busy at work recently, so I took some time in the evening to sort out the scenarios in which json strings and json arrays are returned in the background during ajax requests, as well as processing examples in the front desk.

Look at the code directly.

Background response of json string

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);
 }
}

Background response of json array

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);
 }
}

Foreground page

<%@ 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>

Page rendering

The effect after clicking the JsonStr and JsonArr buttons

The above is what I compiled for everyone , I hope it will be helpful to everyone in the future.

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