使用AJAX（包含正则表达式）验证用户登录的步骤

我们来分一下步骤吧：

1.HTML代码，页面先写出来；

2.正则表达式验证输入的用户名密码是否正确，失去焦点验证

3.Ajax异步提交

4.servlet这是后台处理代码获取数据并对比响应，然后跳转成功页面

效果图：

结构：

代码如下：

<%@ page language=\”java\” import=\”java.util.*\” pageEncoding=\”utf-8\”%>
<!DOCTYPE HTML PUBLIC \”-//W3C//DTD HTML 4.01 Transitional//EN\”>
<html>
<head>
<script type=\”text/javascript\” src=\”JS/jQuery.js\”></script>
<style type=\”text/css\”>
table {
width: 360px;
height: 45px:
text-align: center;
margin-top: 120px;
border-collapse: collapse;
}

input {
width: 280px;
height: 30px;
}
</style>
</head>
<body>
<form action=\”#\” method=\”post\”>
<center>
<table align=\”center\” border=\”1\”>
<tr>
<td>用户名:</td>
<td><input type=\”text\” name=\”name\” id=\”username\”
onblur=\”verifyName()\” /></td>
</tr>
<tr>
<td>密码:</td>
<td><input type=\”text\” name=\”pwd\” id=\”mypwd\”
onblur=\”verifyPwd()\” /></td>
</tr>
<tr>
<td colspan=\”3\” align=\”center\” height=\”36px\”><input
type=\”button\” style=\”width: 8rem;height:27px\” value=\”提交登录验证\” /></td>
</tr>
</table>
</center>
</form>
<script type=\”text/javascript\”>
function verifyName() {
//用户名校验
var verifyName = document.getElementById(\”username\”).value;
var name = /^[A-Z][0-9A-Za-z_][a-zA-Z0-9_]{5,19}$/; // 大写字母开头 6-20位字符(不允许有符号但是允许有_)
if (!name.test(verifyName)) {
//$(\”#username\”).after(\”<span>大写字母开头6-20位字符(不允许有符号但是允许有_)</span>\”);
$(\”#username\”).css(\”border-color\”, \”red\”);
return false;
} else {
return true;
}
}
function verifyPwd() {
//密码
var verifyPwd = document.getElementById(\”mypwd\”).value;
var pwd = /^[A-Z][A-Za-z0-9]\\w{7,14}.{1,20}$/; //大写开头数字字母符号混合 8-15位
if (!pwd.test(verifyPwd)) {
$(\”#username\”).css(\”border-color\”, \”red\”);
return false;
} else {
return true;
}
}

$(function() {
$(\”:button\”).on(\”click\”, function() {
$.ajax({
type : \”post\”,
url : \”AJAXServlet\”,
data : {
name : $(\”#username\”).val(),
pwd : $(\”#mypwd\”).val()
},
dataType : \”text\”,
success : function(data) {
if (data == \”ok\”) {
window.location.href = \”show.jsp\”;
} else {
alert(\”登录失败！\”);
$(\”#mypwd\”).val(\”\”);
$(\”#username\”).focus().select();
}
}
});
});
});
</script>
</body>
</html>

servlet代码：

package com.chaz.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class AJAXServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType(\”text/html;charset=utf-8\”);
request.setCharacterEncoding(\”utf-8\”);
PrintWriter out = response.getWriter();

String name = \”ZhangSan\”;
String pwd = \”Zhang123456\”;

String ajaxName = request.getParameter(\”name\”);
String ajaxPwd = request.getParameter(\”pwd\”);
System.out.println(ajaxName+\”:\”+ajaxPwd);
if(name.equals(ajaxName)&&pwd.equals(ajaxPwd)){
out.print(\”ok\”);
}else{
out.print(\”Error\”);
}
out.flush();
out.close();
}
}

web.xml:

<?xml version=\”1.0\” encoding=\”UTF-8\”?>
<web-app version=\”3.0\”
xmlns=\”http://java.sun.com/xml/ns/javaee\”
xmlns:xsi=\”http://www.w3.org/2001/XMLSchema-instance\”
xsi:schemaLocation=\”http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd\”>
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>AJAXServlet</servlet-name>
<servlet-class>com.chaz.servlet.AJAXServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>AJAXServlet</servlet-name>
<url-pattern>/AJAXServlet</url-pattern>
</servlet-mapping>

</web-app>

跳转成功页面就这个😄：

总结

以上所述是小编给大家介绍的使用AJAX（包含正则表达式）验证用户登录的步骤,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对悠久资源网网站的支持！
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