1、流程图：
2、代码清单
数据库脚本：
1 DROP TABLE IF EXISTS `user`; 2 3 CREATE TABLE `user` ( 4 `userid` varchar(30) NOT NULL, 5 `name` varchar(30) NOT NULL, 6 `password` varchar(30) NOT NULL, 7 PRIMARY KEY (`userid`) 8 ) ENGINE=InnoDB DEFAULT CHARSET=utf8; 9 10 INSERT INTO `user` VALUES ('admin', 'administrator', 'admin');
User 类：
1 package com.shawn.mvcdemo.vo; 2 3 public class User{ 4 private String userID; 5 6 private String name; 7 8 private String password; 9 10 public String getUserID(){ 11 return this.userID; 12 } 13 14 public String getName(){ 15 return this.name; 16 } 17 18 public String getPassword(){ 19 return this.password; 20 } 21 22 public void setUserID(String userID){ 23 this.userID = userID; 24 } 25 26 public void setName(String name){ 27 this.name = name; 28 } 29 30 public void setPassword(String password){ 31 this.password = password; 32 } 33 34 }
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DatabaseConnection 类：
1 package com.shawn.mvcdemo.dbc; 2 3 import java.sql.*; 4 5 public class DatabaseConnection{ 6 private static final String DBDRIVER = "org.gjt.mm.mysql.Driver"; //数据库驱动 7 private static final String DBURL = "jdbc:mysql://localhost:3306/mldn"; //数据库URL 8 private static final String DBUSER = "root"; //用户名 9 private static final String DBPASSWORD = "root"; //密码 10 11 private Connection conn = null; 12 13 public DatabaseConnection() throws Exception{ 14 try{ 15 Class.forName(DBDRIVER); 16 this.conn = DriverManager.getConnection(DBURL,DBUSER,DBPASSWORD); 17 } catch(Exception e){ 18 throw e; 19 } 20 } 21 22 public Connection getConnection(){ 23 return this.conn; 24 } 25 26 public void close() throws Exception{ 27 if(this.conn != null){ 28 try{ 29 this.conn.close(); 30 } catch(Exception e){ 31 throw e; 32 } 33 } 34 } 35 36 public static void main(String args[]){ 37 try{ 38 System.out.println(new DatabaseConnection().getConnection()); 39 } catch(Exception e){ 40 e.printStackTrace(); 41 } 42 } 43 }
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IUserDAO 接口：
1 package com.shawn.mvcdemo.dao; 2 3 import com.shawn.mvcdemo.vo.User; 4 5 public interface IUserDAO{ 6 //现在完成的是登录验证，那么登录操作只有两种返回结果 7 public boolean findLogin(User user) throws Exception; 8 }
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UserDAOImpl 类：
1 package com.shawn.mvcdemo.dao.impl; 2 3 import java.sql.*; 4 5 import com.shawn.mvcdemo.vo.User; 6 import com.shawn.mvcdemo.dbc.*; 7 import com.shawn.mvcdemo.dao.*; 8 9 public class UserDAOImpl implements IUserDAO{ 10 private Connection conn = null; 11 12 private PreparedStatement pstmt = null; 13 14 public UserDAOImpl(Connection conn){ 15 this.conn = conn; 16 } 17 18 public boolean findLogin(User user) throws Exception{ 19 boolean flag = false; 20 String sql = "select name from user where userid = ? and password = ?"; 21 this.pstmt = this.conn.prepareStatement(sql); 22 this.pstmt.setString(1,user.getUserID()); 23 this.pstmt.setString(2,user.getPassword()); 24 ResultSet rs = this.pstmt.executeQuery(); 25 if(rs.next()){ 26 user.setName(rs.getString("name")); 27 flag = true; 28 } 29 this.pstmt.close(); 30 return flag; 31 } 32 }
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UserDAOProxy 类：
1 package com.shawn.mvcdemo.dao.proxy; 2 3 import java.sql.*; 4 5 import com.shawn.mvcdemo.vo.User; 6 import com.shawn.mvcdemo.dbc.*; 7 import com.shawn.mvcdemo.dao.*; 8 import com.shawn.mvcdemo.dao.impl.*; 9 10 public class UserDAOProxy implements IUserDAO{ 11 private DatabaseConnection dbc = null; 12 private IUserDAO dao = null; 13 14 public UserDAOProxy(){ 15 try{ 16 this.dbc = new DatabaseConnection(); 17 } catch(Exception e){ 18 e.printStackTrace(); 19 } 20 this.dao = new UserDAOImpl(this.dbc.getConnection()); 21 } 22 23 public boolean findLogin(User user) throws Exception{ 24 boolean flag = false; 25 try{ 26 flag = this.dao.findLogin(user); //调用真实主题，完成操作 27 } catch(Exception e){ 28 throw e; 29 } finally{ 30 this.dbc.close(); 31 } 32 return flag; 33 } 34 35 36 }
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DAOFactory 类：
1 package com.shawn.mvcdemo.factory; 2 3 import com.shawn.mvcdemo.dao.*; 4 import com.shawn.mvcdemo.dao.proxy.*; 5 6 public class DAOFactory{ 7 public static IUserDAO getIUserDAOInstance(){ 8 return new UserDAOProxy(); 9 } 10 }
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LoginServlet 类：
1 package com.shawn.mvcdemo.servlet; 2 3 import java.io.*; 4 import java.util.*; 5 6 import javax.servlet.*; 7 import javax.servlet.http.*; 8 import com.shawn.mvcdemo.factory.*; 9 import com.shawn.mvcdemo.vo.*; 10 11 public class LoginServlet extends HttpServlet{ 12 13 public void doGet(HttpServletRequest req,HttpServletResponse resp) 14 throws ServletException,IOException{ 15 String path = "login.jsp"; 16 String userID = req.getParameter("userID"); 17 String password = req.getParameter("password"); 18 List<String> info = new ArrayList<String>();//收集错误信息 19 if(userID == null || "".equals(userID)){ 20 info.add("用户id不能为空！"); 21 } 22 if(password == null || "".equals(password)){ 23 info.add("密码不能为空！"); 24 } 25 if(info.size() == 0){//里面没有记录任何的错误 26 User user = new User(); 27 user.setUserID(userID); 28 user.setPassword(password); 29 try{ 30 if(new DAOFactory().getIUserDAOInstance().findLogin(user)){ 31 info.add("用户登陆成功，欢迎" + user.getName() + "光临！"); 32 System.out.println(1); 33 } else { 34 info.add("用户登录失败，错误的用户名和密码！"); 35 System.out.println(2); 36 } 37 }catch(Exception e){ 38 e.printStackTrace(); 39 } 40 } 41 req.setAttribute("info",info); 42 req.getRequestDispatcher(path).forward(req,resp); 43 } 44 45 public void doPost(HttpServletRequest req,HttpServletResponse resp) 46 throws ServletException,IOException{ 47 this.doGet(req,resp); 48 } 49 50 }
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login.jsp 页面：
1 <%@ page contentType="text/html" pageEncoding="utf-8" import="java.util.*"%> 2 <html> 3 <head> 4 <title>www.mldnjava.cn, MLDN高端Java培训</title> 5 <% 6 request.setCharacterEncoding("utf-8"); 7 %> 8 <% 9 List<String> info = (ArrayList<String>)request.getAttribute("info"); 10 String userID = request.getParameter("userID"); 11 String password = request.getParameter("password"); 12 %> 13 <script> 14 window.onload = function(){ 15 var objForm = document.getElementById("form1"); 16 17 objForm.onsubmit = function(){ 18 if(!(/^\w{5,15}$/.test(this.userID.value))){ 19 alert("用户ID必须是5~15位！"); 20 this.userID.focus(); 21 return false; 22 } 23 24 if(!(/^\w{5,15}$/.test(this.password.value))){ 25 alert("密码必须是5~15位！"); 26 this.password.focus(); 27 return false; 28 } 29 } 30 31 } 32 33 </script> 34 </head> 35 36 <body> 37 <form id="form1" action="login" method="post"> 38 用户ID：<input type="text" name="userID" value="<%= (userID == null) ? "" : userID %>" /><br> 39 密 码：<input type="password" name="password" value="<%= (password == null) ? "" : password %>" /><br> 40 <input type="submit" value="登录" /> 41 <input type="reset" value="重置" /> 42 </form> 43 <% 44 if(info != null){ 45 for(String str : info){ 46 %> 47 <h3><%=str %></h3> 48 <% 49 } 50 } 51 %> 52 </body> 53 </html>
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web.xml 配置：
1 <?xml version="1.0" encoding="ISO-8859-1"?> 2 3 <web-app xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 6 version="2.5"> 7 8 <display-name>Hello World!</display-name> 9 <welcome-file-list> 10 <welcome-file>main.html</welcome-file> 11 </welcome-file-list> 12 13 <servlet> 14 <servlet-name>login</servlet-name> 15 <servlet-class>com.shawn.mvcdemo.servlet.LoginServlet</servlet-class> 16 </servlet> 17 18 <servlet-mapping> 19 <servlet-name>login</servlet-name> 20 <url-pattern>/mvclogin/login</url-pattern> 21 </servlet-mapping> 22 </web-app>
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