javaweb登录

1.login,jsp

 账号: 

 密码: 

   

2.loginServlet

package li.servlet;

import java.io.IOException;
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 li.pojo.User;
import li.service.UserService;
import li.service.impl.UserServiceImpl;


@WebServlet("/loginServlet")
public class loginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    
    public loginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		req.setCharacterEncoding("utf-8");
		resp.setContentType("html/text;charset=utf-8");
		String name=req.getParameter("username");
		String pwd=req.getParameter("pwd");
		
		UserService service=new UserServiceImpl();
		User u=service.select(name,pwd);
        if(u!=null){
			req.getRequestDispatcher("/index.jsp").forward(req, resp);
		}
	}

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

}

3.service   serviceimpl

package li.service;

import li.pojo.User;

public interface UserService {

	User select(String name, String pwd);

}


package li.service.impl;

import li.dao.UserDao;
import li.dao.impl.UserDaoImpl;
import li.pojo.User;
import li.service.UserService;

public class UserServiceImpl implements UserService {
     UserDao db=new UserDaoImpl();
	@Override
	public User select(String name, String pwd) {
		// TODO Auto-generated method stub
		return db.select(name,pwd);
	}

}

4.dao  daoimpl

package li.dao;

import li.pojo.User;

public interface UserDao {

	User select(String name, String pwd);

}




package li.dao.impl;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import li.dao.UserDao;
import li.pojo.User;


public class UserDaoImpl implements UserDao {

	@Override
	public User select(String name, String pwd) {
		// TODO Auto-generated method stub
		Connection conn=null;
		PreparedStatement ps=null;
		ResultSet rs=null;
		User u=null;
		
		
		try {
			//加载驱动
			Class.forName("com.mysql.jdbc.Driver");
			//获取连接
			conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/ff?useUnicode=true&characterEncoding=utf8","root","1234");
			//创建SQL语句
			String sql="select * from stu where username=? and pwd=?";
			//预处理
			ps=conn.prepareStatement(sql);
			//添加占位符
			ps.setString(1, name);
			ps.setString(2, pwd);
			//执行SQL语句
			rs=ps.executeQuery();
			//遍历
			while(rs.next()){
				u=new User();
				u.setId(rs.getInt("id"));
				u.setUsername(rs.getString("username"));
				u.setPwd(rs.getString("pwd"));
			}
			
			
		} catch (Exception e) {
			// TODO: handle exception
			e.printStackTrace();
		}finally{
			//关闭资源
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				ps.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
		//返回查询结果
		return u;
	}

}

5.index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>







   成功

6.数据库

在localhost链接名下创建ff数据库，在ff数据库下创建stu表，创建username和pwd字段，定义为String类型