servlet——登录练习（登录页面&登录请求&登录请求处理）

导入Java包   放在这个目录下

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目录的流程:

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登录流程

登录练习:
    1、创建登录页面
        创建Servlet进行登录页面请求处理
    2、点击登录完成登录操作
        浏览器发送请求到服务器(用户信息+其他数据)
        服务器调用对应的servlet进行处理
            设置响应编码格式
            获取请求信息
            处理请求信息     
            响应处理结果
    3、在servlet中完成用户登录校验
            需要连接数据库(在mySql中创建用户表)
    使用MVC思想完成

1、创建登录页面

        创建Servlet进行登录页面请求处理

package com.dym.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class PageServlet extends HttpServlet {
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		//设置相应编码格式
			resp.setContentType("text/html;charset=utf-8");
		//获取请求信息
		//处理请求
		//响应处理结果
			resp.getWriter().write("");
			resp.getWriter().write("");
			resp.getWriter().write("");
			resp.getWriter().write("");
			resp.getWriter().write("
");
			resp.getWriter().write("用户名：
");
			resp.getWriter().write("密码：
");
			resp.getWriter().write("
");
			resp.getWriter().write("
");
			resp.getWriter().write("");
			resp.getWriter().write("");
	}
}

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2、点击登录完成登录操作

            浏览器发送请求到服务器(用户信息+其他数据)
            服务器调用对应的servlet进行处理
            设置响应编码格式
            获取请求信息
            处理请求信息     
            响应处理结果

User.java

package com.dym.pojo;

public class User {
	private int uid;
	private String uname;
	private String pwd;
	public int getUid() {
		return uid;
	}
	public void setUid(int uid) {
		this.uid = uid;
	}
	public String getUname() {
		return uname;
	}
	public void setUname(String uname) {
		this.uname = uname;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	@Override
	public String toString() {
		return "User [uid=" + uid + ", uname=" + uname + ", pwd=" + pwd + "]";
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((pwd == null) ? 0 : pwd.hashCode());
		result = prime * result + uid;
		result = prime * result + ((uname == null) ? 0 : uname.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		User other = (User) obj;
		if (pwd == null) {
			if (other.pwd != null)
				return false;
		} else if (!pwd.equals(other.pwd))
			return false;
		if (uid != other.uid)
			return false;
		if (uname == null) {
			if (other.uname != null)
				return false;
		} else if (!uname.equals(other.uname))
			return false;
		return true;
	}
	public User() {
		super();
		// TODO Auto-generated constructor stub
	}
	public User(int uid, String uname, String pwd) {
		super();
		this.uid = uid;
		this.uname = uname;
		this.pwd = pwd;
	}
	
	
	
	
}

LoginService.java 

package com.dym.service;

import com.dym.pojo.User;

public interface LoginService {
	User checkLoginService(String uname,String pwd);
	}

LoginServiceImpl.java

package com.dym.service.impl;

import com.dym.dao.LoginDao;
import com.dym.dao.impl.LoginDaoImpl;
import com.dym.pojo.User;
import com.dym.service.LoginService;

public class LoginServiceImpl implements LoginService{
	//创建Dao层对象
	LoginDao ld=new LoginDaoImpl();
	@Override
	public User checkLoginService(String uname, String pwd) {
		
		return ld.checkLoginDao(uname, pwd);
	}
}

LoginDao.java

package com.dym.dao;

import com.dym.pojo.User;

public interface LoginDao {
	//根据用户名和密码获取用户信息
	User checkLoginDao(String uname,String pwd);
	//根据uid获取用户信息
	User checkUidDao(String uid);
}

LoginDaoImpl.java

package com.dym.dao.impl;

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

import com.dym.dao.LoginDao;
import com.dym.pojo.User;


public class LoginDaoImpl implements LoginDao{
	@Override
	public User checkLoginDao(String uname, String pwd) {
		//声明jdbc对象
		Connection conn=null;
		PreparedStatement ps=null;
		ResultSet rs=null;
        //声明数据存储对象
		User u=null;
		try {
			//加载驱动
			Class.forName("com.mysql.jdbc.Driver");
			//获取连接对象
			conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/wollo","root","123456");
			//创建sql命令
			String sql="select * from t_user where uname=? and pwd=?";
			//创建sql命令对象
			ps=conn.prepareStatement(sql);
			//给占位符赋值
			ps.setString(1, uname);
			ps.setString(2, pwd);
			//执行
			rs=ps.executeQuery();
			//遍历执行结果
			while(rs.next()){
				u=new User();
				u.setUid(rs.getInt("uid"));
				u.setUname(rs.getString("uname"));
				u.setPwd(rs.getString("pwd"));
			}
		} catch (Exception e) {
			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();
			}
		}
		return u;
	}
	//根据UID获取用户信息
		@Override
		public User checkUidDao(String uid) {
				//声明Jdbc对象
					Connection conn=null;
					PreparedStatement ps=null;
					ResultSet rs=null;
					//声明数据存储对象
					User u=null;
					try {
						//加载驱动
						Class.forName("com.mysql.jdbc.Driver");
						//获取连接对象
						conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/407","root","1234");
						//创建Sql命令
						String sql="select * from t_user where uid=?";
						//创建Sql命令对象
						ps=conn.prepareStatement(sql);
						//给占位符赋值
						ps.setString(1, uid);
						//执行
						rs=ps.executeQuery();
						//遍历执行结果
						while(rs.next()){
							u=new User();
							u.setUid(rs.getInt("uid"));
							u.setUname(rs.getString("uname"));
							u.setPwd(rs.getString("pwd"));
						}
						//关闭资源
					} catch (Exception e) {
						e.printStackTrace();
					}finally{
						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
					return u;
		}
}

LoginServlet.java

package com.dym.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.dym.pojo.User;
import com.dym.service.LoginService;
import com.dym.service.impl.LoginServiceImpl;

public class LoginServlet extends HttpServlet {
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		//设置响应编码格式
			resp.setContentType("text/html;charset=utf-8");
		//获取请求信息
			String uname=req.getParameter("uname");
			uname=new String(uname.getBytes("iso8859-1"),"utf-8");  //解决了乱码问题
			String pwd=req.getParameter("pwd");
			System.out.println(uname+":"+pwd);
		//处理请求信息
			//获取业务层对象
			LoginService ls=new LoginServiceImpl();
			User u=ls.checkLoginService(uname, pwd);
			System.out.println(u);
		//响应处理结果
			if(u!=null){
				resp.getWriter().write("登录成功");
			}else{
				resp.getWriter().write("登录失败");
			}
	}
}

 

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