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Ajax simple practical case

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Release： 2018-03-31 17:23:29

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This time I will bring you a simple practical case of Ajax. What are the precautions of Ajax in actual combat? The following is a practical case, let's take a look.

I will implement a simple Ajax page user verification case without refreshing:

The effect is as follows:

The main process of implementation:

Receive and verify the form data in the foreground in the checkUser method in the UsersAction class. According to different situations, return a status code code to the jsp page, and then accept the background transmission through the $.post method in ajax1.jsp. The status code

makes different responses.

The specific code is as follows:

1. Entity class

package com.bean;
import java.io.Serializable;
public class Users implements Serializable {
 private String uname;
 private String passwd;
 public String getUname() {
  return uname;
 }
 public void setUname(String uname) {
  this.uname = uname;
 }
 public String getPasswd() {
  return passwd;
 }
 public void setPasswd(String passwd) {
  this.passwd = passwd;
 }
 public Users(String uname, String passwd) {
  super();
  this.uname = uname;
  this.passwd = passwd;
 }
 public Users() {
  super();
 }
}

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2. Action class

package com.action;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.convention.annotation.Action;
import com.bean.Users;
public class UsersAction {
 private Users us;
 public Users getUs() {
  return us;
 }
 public void setUs(Users us) {
  this.us = us;
 }
 @Action(value="checkUser")
 public String checkUser() {
  System.out.println("aaaaaaaaa");
  HttpServletResponse response = ServletActionContext.getResponse();
  response.setCharacterEncoding("utf-8");
  try {
   PrintWriter out = response.getWriter();
   int code = 0;
   if (us == null) {
    out.print(0);
    return null;
   } else {
    if (us.getUname() == null || us.getUname().trim().equals("")) {
     code = 1;
     out.print(code);
     return null;
    } else {
     if (us.getPasswd() == null
       || us.getPasswd().trim().equals("")) {
      code = 2;
      out.print(code);
      return null;
     } else {
      code = 200;
      out.print(code);
     }
    }
   }
   out.flush();
   out.close();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return null;
 }
}

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3.ajax1.jsp

<%@ 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>
 <base href="<%=basePath%>" rel="external nofollow" >
 <title>Ajax练习</title>
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0"> 
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" >
 -->
<script type="text/javascript" src="js/jquery-1.9.1.js"></script>
<script>
 $(function() {
  $("#btok").click(function() {
   //获取数据
   var uname = $("#uname").val();
   var passwd = $("#passwd").val();
   //将数据组织为json格式
   var json = {"us.uname":uname,"us.passwd":passwd};
   //进行异步请求
   $.post("checkUser.action",json,function(msg){
    if(msg == '0') {
     alert("用户名和密码错误！");
     return;
    }
    if(msg == '1') {
     $("#uerror").html("用户名错误！");
     return;
    } else {
     $("#uerror").html("*");
    }
    if(msg == '2') {
     $("#perror").html("密码错误！");
     return;
    } else {
     $("#perror").html("*");
    }
    if(msg == '200') {
     alert("登陆成功！");
     return;
    }
   });
  });
 });
</script>
 </head>
 <body>
 <form name="form1" method="post" action="">
 <table width="450" border="1" align="center" cellpadding="1" cellspacing="0">
  <tr>
  <td colspan="2" align="center" valign="middle" bgcolor="#FFFFCC">用户注册</td>
  </tr>
  <tr>
  <td width="88">账号:</td>
  <td width="352"><label for="uname"></label>
  <input type="text" name="uname" id="uname">
  <span id="uerror" style="color:#F06;">*</span></td>
  </tr>
  <tr>
  <td>密码:</td>
  <td><label for="passwd"></label>
  <input type="password" name="passwd" id="passwd">
  <span id="perror" style="color:#F06;">*</span></td>
  </tr>
  <tr align="center" valign="middle" bgcolor="#FFFFCC">
  <td colspan="2"><input type="button" name="button" id="btok" value="确定">
  <input type="reset" name="button2" id="button2" value="重置"></td>
  </tr>
 </table>
 </form>
 <br>
 </body>
</html>

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!