一个简单的登录页

#1
login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<%
		Object o=request.getParameter("error");
		if(o!=null){
			out.println("用户名或密码错误！");
		}
	%>
	<form action="/javawebdemo3/login" method="get">
	<table>
		<tr>
		<td>用户名：</td>
		<td><input type="text" name="username"> </td>
		</tr>
		<tr>
		<td>密码：</td>
		<td><input type="password" name="password"> </td>
		</tr>
		<tr>
		<td colspan="2">
		<input type="submit" value="登录">
		<input type="reset" value="重填">
		</td>
		</tr>
		</table>
	</form>
</body>
</html>

#2
loginServlet.java

package com.neu.servlet;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

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 com.neu.entity.Emp;
import com.neu.entity.dept;

/**
 * Servlet implementation class loginServlet
 */
@WebServlet("/login")
public class loginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
   
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("utf-8");
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		//处理
		if("admin".equals(username)&&"123".equals(password)) {
			//把登录名放到request中
			request.setAttribute("username", username);
			List<dept> list=new ArrayList();
			dept dept=new dept(10,"人力资源部","沈阳");
			list.add(dept);
			dept=new dept(20,"生产部","大连");
			list.add(dept);
			dept=new dept(30,"销售部","沈阳");
			list.add(dept);
			request.setAttribute("list", list);
			
			/*List<Emp> list1 = new ArrayList();
			SimpleDateFormat d=new SimpleDateFormat("yyyy-MM-dd");
			Emp emp = new Emp(001,"张三","文员",d.parse("1988-08-12"));
			list1.add(emp);
			
			emp = new Emp(002,"李四","销售员",d.parse("1990-12-01"));
			list1.add(emp);
			
			emp = new Emp(003,"王五","程序员",d.parse("1992-05-22"));
			list1.add(emp);*/
			//请求转发到jsp页
			request.getRequestDispatcher("/main.jsp").forward(request, response);
		}else {
			//重定向回原来的登录页
			response.sendRedirect(request.getContextPath()+"/login.jsp?error=true");
		}
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

#3
main.jsp

<%@page import="com.neu.entity.dept"%>
<%@page import="java.util.List"%>
<%@ 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>Insert title here</title>
</head>
<body>
	登录名：<%=request.getAttribute("username") %>
	<p></p>
	<table border="1" width="300">
	<%
	List<dept> list=(List<dept>)request.getAttribute("list");
	for(dept d:list){
		%>
		<tr>
		<td><%=d.getDeptno() %></td>
		<td><%=d.getDname() %></td>
		<td><%=d.getLoc() %></td>
		</tr>
		<%
	}
	%>
	</table>
</body>
</html>