1. 目录

     

    DBConn.java

    login.jsp

    main.jsp

    error.jsp

    LoginServlet.java

    web.xml

    Login.java

    LoginDao.java

  2. DBConn.java

    package org.db;
import java.sql.*;
public class DBConn {
	public static Connection conn;//创建Connection连接对象conn
	//已获取数据库连接
	public static Connection getConn(){
		try{
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");//Class.forName方法加载注册SQL Server 2014的JDBC驱动
			conn=DriverManager.getConnection("jdbc:sqlserver://localhost:1433;databaseName=MBOOK","sa","5678");//编写连接字符串conn,创建获取连接
			return conn;
		}catch(Exception e){
			e.printStackTrace();
			return null;
		}
	}
	public static void CloseConn(){
		try{
			conn.close();//自带函数关闭连接
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}

     

  3. login.jsp

    <%@page lanuage="java" pageEncoding="gb2312"%>
<html>
<head>
<title>图书管理系统</title></head>
<body bgcolor="#71CABC">
<form action="longinServlet" method="post">
	<table>
		<caption>用户登录</caption>
		<tr>
			<td>登录名</td>
			<td><input name="name" type="text" size="22"/></td>
		</tr>
		<tr>
			<td>密码</td>
			<td><input name="password" type="password" size="22"/></td>		
		</tr></table>
	<input type="submit" value="登录"/>
	<input type="reset" value="重置"/>
</form></body></html>

     

  4. main.jsp

    <%@ page language="java" pageEncoding="gb2312" import="org.model.Login" %>
<html>
<head>
	<title>欢迎使用</title>
</head>
<body>
	<%
		Login login=(Login)session.getAttribute("login");	//从会话中取出 Login 对象
		String lgn=login.getName();							//通过 JavaBean 对象获取用户名
	%>
	<%=lgn%>，您好！欢迎使用图书管理系统。
</body>
</html>

     

  5. error.jsp

    <%@ page language="java" pageEncoding="gb2312"%>
<html>
<head>
	<title>出错</title>
</head>
<body>
	登录失败！单击<a href="login.jsp">这里</a>返回
</body>
</html>

     

  6. LoginServlet.java

    /**
 * 
 */
/**
 * @author 123
 *
 */
package org.servlet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.model.*;
import org.dao.*;
public class LoginServlet extends HttpServlet{
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
		request.setCharacterEncoding("gb2312");
		LoginDao loginDao = new LoginDao();
		Login l= loginDao.checkLogin(request.getParameter("name"),request.getParameter("password"));
		if(l!=null){
			HttpSession session=request.getSession();
			session.setAttribute("login", 1);
			response.sendRedirect("main.jsp");
		}else{
			response.sendRedirect("error.jsp");
		}
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
		doGet(request,response);
	}
}

     

  7. web.xml

    <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <servlet>
  	<servlet-name>loginServlet</servlet-name>
  	<servlet-class>org.servlet.LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>loginServlet</servlet-name>
  	<url-pattern>/loginServlet</url-pattern>
  </servlet-mapping>
</web-app>

     

  8. Login.java

    /**
 * 
 */
/**
 * @author 123
 *
 */
package org.model;
public class Login{
	private Integer id;
	private String name;
	private String password;
	private boolean role;
	public Integer getId(){
		return this.id;
	}
	public void setId(Integer id){
		this.id=id;
	}
	public String getName(){
		return this.name;
	}
	public void setName(String name){
		this.name=name;
	}
	public String getPassword(){
		return this.password;
	}
	public void setPassword(String password){
		this.password=password;
	}
	public boolean getRole(){
		return this.role;
	}
	public void setRole(boolean role){
		this.role=role;
	}
}

     

  9. LoginDao.java

    package org.dao;
import java.sql.*;
import org.model.*;
import org.db.*;
public class LoginDao{
	Connection conn;
	public Login checkLogin(String name, String password){
		try{
			conn=DBConn.getConn();
			PreparedStatement pstmt = conn.prepareStatement("select * from [login] where name=?"+"and password=?");
			pstmt.setString(1, name);
			pstmt.setString(2, password);
			ResultSet rs=pstmt.executeQuery();
			if(rs.next()){
				Login login=new Login();
				login.setId(rs.getInt(1));
				login.setName(rs.getString(2));//怎么分清这两个方法呢？
				login.setPassword(rs.getString(3));
				login.setRole(rs.getBoolean(4));
				return login;
			}
			return null;
		}catch(Exception e){
			e.printStackTrace();
			return null;
		}finally{
			DBConn.CloseConn();
		}
	}
}