Java_Web之分层架构

package DB;

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

/**
 * 数据库连接帮助类
 * @author Administrator
 *
 */
public class BaseDao {
    //=======数据库连接信息========
    static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
    static String username = "news";
    static String password = "news";
    static String driverClassName = "oracle.jdbc.driver.OracleDriver";
    
    //获取数据库连接
    public static Connection getConnection(){
        
        Connection connection = null;
        
        try {
            //加载驱动
            Class.forName(driverClassName);
            
            //获取连接
            connection = DriverManager.getConnection(url,username,password);
            
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        return connection;
    }
    
    /*
     * 释放连接
     * */
    public void close_con(Connection connection,Statement st,ResultSet rs){
        
        try {
            if(connection!= null){
                connection.close();
            }
            if(st!= null){
                st.close();
            }
            if(rs!= null){
                rs.close();
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
}

package entity;

/**
 * 用户实体
 * @author Administrator
 *
 */
public class User {
    
    private String username;
    private String password;
    
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    
}

package Dao;
import java.util.List;

import entity.User;

/**
 * 用户数据访问层接口
 * @author Administrator
 *
 */
public interface UserDao {
    
    /**
     * 查询用户是否存在
     * @param user
     * @return
     */
    public boolean findUser(User user);
    
    /**
     * 查询用户列表
     */
    public List<User> findUserList();

}

package Dao.Impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import DB.BaseDao;
import Dao.UserDao;
import entity.User;

/**
 * 用户数据访问层实现类
 * @author Administrator
 * 继承数据库连接类
 */
public class UserDaoImpl extends BaseDao implements UserDao {
    
    //数据库连接对象
    Connection conn = null;
    PreparedStatement stm = null;
    ResultSet rs = null;
    
    /**
     * 实现查询用户功能
     */
    public boolean findUser(User user) {
        //获得连接
        conn = this.getConnection();
        //编写sql
        String sql = "select * from news_users where uname = ? and upwd = ?";
        try {
            
            //得到预编译对象
            stm = conn.prepareStatement(sql);
            stm.setString(1, user.getUsername());
            stm.setString(2, user.getPassword());
            
            //执行sql得到结果集
            rs = stm.executeQuery();

            return rs.next();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            //释放连接
            this.close_con(conn, stm, rs);
        }
        
        return false;
    }
    
    /**
     * 查询用户列表
     */
    public List<User> findUserList() {
        //获得连接
        conn = this.getConnection();
        //编写sql
        String sql = "select * from news_users";
        
        //创建泛型集合
        List<User> userlist = new ArrayList<User>();
        try {
            
            //得到预编译对象
            stm = conn.prepareStatement(sql);
            
            //执行sql得到结果集
            rs = stm.executeQuery();
            while(rs.next()){
                User user = new User();
                user.setUsername(rs.getString(2));
                user.setPassword(rs.getString(3));
                
                userlist.add(user);
            }
            
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        }finally{
            //释放连接
            this.close_con(conn, stm, rs);
        }
        
        return userlist;
    }

}

package Biz;

import java.util.List;

import entity.User;

/**
 * 用户业务逻辑层接口
 * @author Administrator
 *
 */
public interface UserBiz {
    
    /**
     * 用户登录
     * @param user
     * @return
     */
    public boolean login(User user);
    
    /**
     * 查询用户列表
     */
    public List<User> finduserList();

}

import Dao.UserDao;
import Dao.Impl.UserDaoImpl;
import entity.User;
/**
 * 用户业务逻辑实现类
 * @author Administrator
 *
 */
public class UserBizImpl implements UserBiz {
    
    //创建数据访问层对象
    UserDao userdao = new UserDaoImpl();
    
    /**
     * 实现登录
     */
    public boolean login(User user) {
        //调用数据访问层查询用户
        return userdao.findUser(user);
    }
    
    /**
     * 查询用户列表
     */
    public List<User> finduserList() {
        // TODO Auto-generated method stub
        return userdao.findUserList();
    }

}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP ‘index.jsp‘ starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
  </head>
  
  <body>
    <form action="dologin.jsp" method="post">
        <p>用户名:<input type="text" name="username" /></p>
        <p>密    码:<input type="password" name="password" /></p>
        <input type="submit" />
    </form>
  </body>
</html>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="Biz.UserBiz"%>
<%@page import="Biz.Impl.UserBizImpl"%>
<%@page import="entity.User"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    
    //调用业务逻辑层
    UserBiz userbiz = new UserBizImpl();
    
    //获取表单项
    request.setCharacterEncoding("utf-8");
    
    String username = request.getParameter("username");
    String password = request.getParameter("password");
    
    //创建用户实体
    User user = new User();
    user.setUsername(username);
    user.setPassword(password);
    
    //实现登录
    boolean f = userbiz.login(user);
    
    if(f){
        request.getRequestDispatcher("success.jsp").forward(request,response);
    }else{
        %>
            <script type="text/javascript">
                alert("用户名或密码错误！");
                location.href="index.jsp";
            </script>
        <%
    }
    
%>