表示層依賴(lài)于業(yè)務(wù)邏輯層，業(yè)務(wù)邏輯層依賴(lài)于數(shù)據(jù)訪(fǎng)問(wèn)層

package DB;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;/** * 數(shù)據(jù)庫(kù)連接幫助類(lèi) * @author Administrator * */public class BaseDao {    //=======數(shù)據(jù)庫(kù)連接信息========    static String url = "jdbc:Oracle:thin:@localhost:1521:orcl";    static String username = "news";    static String passWord = "news";    static String driverClassName = "oracle.jdbc.driver.OracleDriver";        //獲取數(shù)據(jù)庫(kù)連接    public static Connection getConnection(){                Connection connection = null;                try {            //加載驅(qū)動(dòng)            Class.forName(driverClassName);                        //獲取連接            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;    }        /*     * 釋放連接     * */    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;/** * 用戶(hù)實(shí)體 * @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;/** * 用戶(hù)數(shù)據(jù)訪(fǎng)問(wèn)層接口 * @author Administrator * */public interface UserDao {        /**     * 查詢(xún)用戶(hù)是否存在     * @param user     * @return     */    public boolean findUser(User user);        /**     * 查詢(xún)用戶(hù)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;/** * 用戶(hù)數(shù)據(jù)訪(fǎng)問(wèn)層實(shí)現(xiàn)類(lèi) * @author Administrator * 繼承數(shù)據(jù)庫(kù)連接類(lèi) */public class UserDaoImpl extends BaseDao implements UserDao {        //數(shù)據(jù)庫(kù)連接對(duì)象    Connection conn = null;    PreparedStatement stm = null;    ResultSet rs = null;        /**     * 實(shí)現(xiàn)查詢(xún)用戶(hù)功能     */    public boolean findUser(User user) {        //獲得連接        conn = this.getConnection();        //編寫(xiě)sql        String sql = "select * from news_users where uname = ? and upwd = ?";        try {                        //得到預(yù)編譯對(duì)象            stm = conn.prepareStatement(sql);            stm.setString(1, user.getUsername());            stm.setString(2, user.getPassword());                        //執(zhí)行sql得到結(jié)果集            rs = stm.executeQuery();            return rs.next();        } catch (SQLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }finally{            //釋放連接            this.close_con(conn, stm, rs);        }                return false;    }        /**     * 查詢(xún)用戶(hù)列表     */    public List<User> findUserList() {        //獲得連接        conn = this.getConnection();        //編寫(xiě)sql        String sql = "select * from news_users";                //創(chuàng)建泛型集合        List<User> userlist = new ArrayList<User>();        try {                        //得到預(yù)編譯對(duì)象            stm = conn.prepareStatement(sql);                        //執(zhí)行sql得到結(jié)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{            //釋放連接            this.close_con(conn, stm, rs);        }                return userlist;    }}

package Biz;import java.util.List;import entity.User;/** * 用戶(hù)業(yè)務(wù)邏輯層接口 * @author Administrator * */public interface UserBiz {        /**     * 用戶(hù)登錄     * @param user     * @return     */    public boolean login(User user);        /**     * 查詢(xún)用戶(hù)列表     */    public List<User> finduserList();}

import Dao.UserDao;import Dao.Impl.UserDaoImpl;import entity.User;/** * 用戶(hù)業(yè)務(wù)邏輯實(shí)現(xiàn)類(lèi) * @author Administrator * */public class UserBizImpl implements UserBiz {        //創(chuàng)建數(shù)據(jù)訪(fǎng)問(wèn)層對(duì)象    UserDao userdao = new UserDaoImpl();        /**     * 實(shí)現(xiàn)登錄     */    public boolean login(User user) {        //調(diào)用數(shù)據(jù)訪(fǎng)問(wèn)層查詢(xún)用戶(hù)        return userdao.findUser(user);    }        /**     * 查詢(xún)用戶(hù)列表     */    public List<User> finduserList() {        // TODO Auto-generated method stub        return userdao.findUserList();    }}

JSP頁(yè)面

<%@ 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="descrCSS" href="styles.css">    -->  </head>    <body>    <form action="dologin.jsp" method="post">        <p>用戶(hù)名:<input type="text" name="username" /></p>        <p>密    碼:<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+"/";        //調(diào)用業(yè)務(wù)邏輯層    UserBiz userbiz = new UserBizImpl();        //獲取表單項(xiàng)    request.setCharacterEncoding("utf-8");        String username = request.getParameter("username");    String password = request.getParameter("password");        //創(chuàng)建用戶(hù)實(shí)體    User user = new User();    user.setUsername(username);    user.setPassword(password);        //實(shí)現(xiàn)登錄    boolean f = userbiz.login(user);        if(f){        request.getRequestDispatcher("success.jsp").forward(request,response);    }else{        %>            <script type="text/Javascript">                alert("用戶(hù)名或密碼錯(cuò)誤！");                location.href="index.jsp";            </script>        <%    }    %>