Servlet 登录时数据校验

包含JavaScript登陆时校验和服务器端的校验

JSP校验意义
客户端验证：使用JavaScript验证
好处：降低服务器端负担不足：不安全，可以跳过只能进行格式验证，无法进行业务验证（用户名是否存在）
服务器端验证：使用JSP验证
好处：安全可以进行格式验证和业务验证
不足：增加了服务器端的负担建议：同时进行服务器端和客户端验证

导包（Jquery包）

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>登录界面</title><script type="text/javascript" src="js/jquery-1.12.3.min.js"></script><script type="text/javascript">$(function () {$("#uname").blur(function () {//进行用户名的非空校验var val =$("#uname").val();if(val==null||val==""){$("#uname_span").text("用户名不能为空").css("color","red");}else {$("#uname_span").text("用户名合法").css("color","green");}})$("#pwd").blur(function () {//进行密码的非空校验var val =$("#pwd").val();if(val==null||val==""){$("#pwd_span").text("密码不能为空").css("color","red");}else {$("#pwd_span").text("密码合法").css("color","green");}})})</script></head>
<body><h3>用户登录</h3><form action="DoLoginServlet" method="post"><p>账号：<input type="text" name="uname" id="uname"/><span id="uname_span"><%Object   msg= request.getAttribute("msg");if(msg!=null){out.print(msg);}%></span></p><p>密码：<input type="password" name="pwd" id="pwd"><span id="pwd_span"></span></p><p><input type="submit" value="提交"/></p></form></body>
</html>

success.jsp（登录成功界面）

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>成功登录</title>
</head>
<body><h1>成功登录</h1></body>
</html>

fa.jsp(非法登录拦截)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>警告</title>
</head>
<body><h1>滚</h1><h4>好好登┗|｀O′|┛ 嗷~~</h4><h4>想啥呢</h4><h4>滚去正常登陆去</h4>
</body>
</html>

DoLoginServlet.java(servlet流程控制)

package com.java.servlet;
import com.sun.net.httpserver.HttpServer;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;@WebServlet(urlPatterns = "/DoLoginServlet")
public class DoLoginServlet extends HttpServlet {@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//接收数据String uname = req.getParameter("uname");String pwd = req.getParameter("pwd");//服务端校验if(uname==null||"".equals(uname)){req.getRequestDispatcher("fa.jsp").forward(req,resp);return;}//处理数据boolean flage= false;if ("sxt".equals(uname)&&"123".equals(pwd)){flage= true;}//做出响应if (flage){req.getRequestDispatcher("success.jsp").forward(req,resp);}else{req.setAttribute("msg","用户名和密码不匹配");req.getRequestDispatcher("Login.jsp").forward(req,resp);}}
}