zoukankan html css js c++ java

model1模式变为mv模式,实现业务逻辑和画面的分离

增加UserBeanCl类

  1 /**
  2  * 这是一个处理user表的类，操作UserBean
  3  * 业务逻辑在这里
  4  */
  5 package com;
  6 
  7 import java.sql.Connection;
  8 import java.sql.DriverManager;
  9 import java.sql.PreparedStatement;
 10 import java.sql.ResultSet;
 11 import java.sql.SQLException;
 12 import java.util.ArrayList;
 13 
 14 public class UserBeanCl {
 15     // 业务逻辑
 16     private Connection connection = null;
 17     private PreparedStatement preStatement = null;
 18     private ResultSet rs = null;
 19     private int pageCount = 0;
 20 
 21     // 用户验证
 22     public boolean checkUser(String username, String passwd) {
 23         boolean flag = false;
 24         // 得到连接
 25         ConnDB cd = new ConnDB();
 26         connection = cd.getConnection();
 27 
 28         try {
 29             String sql = "select password from db_users where username=?";
 30             preStatement = connection.prepareStatement(sql);
 31             preStatement.setString(1, username);
 32             rs = preStatement.executeQuery();
 33             if (rs.next()) {
 34                 String dpasswd = rs.getString(1);
 35                 if (dpasswd.equals(passwd)) {
 36                     flag = true;
 37                 }
 38             }
 39         } catch (SQLException e) {
 40             // TODO Auto-generated catch block
 41             e.printStackTrace();
 42         } finally {
 43             this.close();
 44         }
 45         return flag;
 46     }
 47 
 48     // 关闭资源
 49     public void close() {
 50         if (rs != null) {
 51             try {
 52                 rs.close();
 53                 rs = null;
 54             } catch (SQLException e) {
 55                 // TODO Auto-generated catch block
 56                 e.printStackTrace();
 57             }
 58         }
 59         if (preStatement != null) {
 60             try {
 61                 preStatement.close();
 62                 preStatement = null;
 63             } catch (SQLException e) {
 64                 // TODO Auto-generated catch block
 65                 e.printStackTrace();
 66             }
 67         }
 68         if (connection != null) {
 69             try {
 70                 connection.close();
 71                 connection = null;
 72             } catch (SQLException e) {
 73                 // TODO Auto-generated catch block
 74                 e.printStackTrace();
 75             }
 76         }
 77     }
 78 
 79     // 分页显示
 80     public ArrayList getResultByPage(int pageNow, int pageSize) {
 81         ArrayList aList = new ArrayList();
 82         int rowCount = 0;
 83         
 84         try {
 85             ConnDB cd = new ConnDB();
 86             connection = cd.getConnection();
 87             preStatement = connection.prepareStatement("select count(*) from db_users");
 88             rs = preStatement.executeQuery();
 89             if (rs.next()) {
 90                 rowCount = rs.getInt(1);
 91             }
 92             // 计算pageCount
 93             if (rowCount % pageSize == 0) {
 94                 pageCount = rowCount / pageSize;
 95             } else {
 96                 pageCount = rowCount / pageSize + 1;
 97             }
 98 
 99             preStatement = connection.prepareStatement("select * from db_users limit ?,?");
100             // 给？赋值
101             preStatement.setInt(1, pageSize * (pageNow - 1));
102             preStatement.setInt(2, pageSize);
103             rs = preStatement.executeQuery();
104             
105             while(rs.next())
106             {
107                 // 将rs中的每条记录封装到UserBean中
108                 UserBean ub = new UserBean();
109                 ub.setUserId(rs.getInt(1));
110                 ub.setUserName(rs.getString(2));
111                 ub.setPassWord(rs.getString(3));
112                 
113                 aList.add(ub);
114             }
115         } catch (Exception e) {
116             // TODO Auto-generated catch block
117             e.printStackTrace();
118         }finally {
119             this.close();
120         }
121         return aList;
122     }
123 
124     public int getPageCount()
125     {
126         return this.pageCount;
127     }
128 }

增加ConnDB类

 1 package com;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 
 6 public class ConnDB {
 7     
 8     private Connection connection=null;
 9     public Connection getConnection()
10     {
11         try {
12             Class.forName("com.mysql.jdbc.Driver");
13             connection =DriverManager.getConnection("jdbc:mysql://localhost/dbjdbc","root","123456");
14         } catch (Exception e) {
15             // TODO Auto-generated catch block
16             e.printStackTrace();
17         }
18         return connection;
19         
20     }
21 
22 }

增加UserBean类

 1 package com;
 2 
 3 public class UserBean {
 4     
 5     private int userId;
 6     private String userName;
 7     private String passWord;
 8     public int getUserId() {
 9         return userId;
10     }
11     public void setUserId(int userId) {
12         this.userId = userId;
13     }
14     public String getUserName() {
15         return userName;
16     }
17     public void setUserName(String userName) {
18         this.userName = userName;
19     }
20     public String getPassWord() {
21         return passWord;
22     }
23     public void setPassWord(String passWord) {
24         this.passWord = passWord;
25     }
26     
27 
28 }

优化后的LoginCl类

 1 package com;
 2 
 3 import javax.servlet.http.Cookie;
 4 import javax.servlet.http.HttpServlet;
 5 import javax.servlet.http.HttpServletRequest;
 6 import javax.servlet.http.HttpServletResponse;
 7 import javax.servlet.http.HttpSession;
 8 
 9 public class LoginCl extends HttpServlet {
10 
11     public void doGet(HttpServletRequest req, HttpServletResponse res) {
12 
13         try {
14             req.setCharacterEncoding("gbk");
15             res.setContentType("text/html;charset=gbk");
16 
17             String username = req.getParameter("username");
18             String password = req.getParameter("password");
19             String sex = req.getParameter("sex");
20             // 用户合法性check
21             UserBeanCl ubc = new UserBeanCl();
22             if (ubc.checkUser(username, password)) {
23                 // 用户合法
24                 // 得到Session
25                 HttpSession hs = req.getSession(true);
26                 // 修改Session存在时间
27                 hs.setMaxInactiveInterval(30);
28                 // Session添加属性pass
29                 hs.setAttribute("pass", "ok");
30 
31                 String keep = req.getParameter("keep");
32                 if (keep != null) {
33                     // 创建Cookie
34                     Cookie name = new Cookie("myname", username);
35                     Cookie pass = new Cookie("mypass", password);
36                     // 设置时间
37                     name.setMaxAge(14 * 24 * 3600);
38                     pass.setMaxAge(14 * 24 * 3600);
39                     // 回写到客户端
40                     res.addCookie(name);
41                     res.addCookie(pass);
42                 }
43                 res.sendRedirect("welcome?uname=" + username + "&upassw=" + password + "&sx=" + sex);
44             } else {
45                 // 说明密码错误
46                 res.sendRedirect("login?info=error1");
47             }
48         } catch (Exception e) {
49             // TODO Auto-generated catch block
50             e.printStackTrace();
51         }
52 
53     }
54 
55     public void doPost(HttpServletRequest req, HttpServletResponse res) {
56         this.doGet(req, res);
57     }
58 
59 }

优化后的Welcome类

  1 package com;
  2 
  3 import java.io.IOException;
  4 import java.io.PrintWriter;
  5 import java.sql.Connection;
  6 import java.sql.DriverManager;
  7 import java.sql.PreparedStatement;
  8 import java.sql.ResultSet;
  9 import java.sql.Statement;
 10 import java.util.ArrayList;
 11 import java.util.concurrent.CountDownLatch;
 12 
 13 import javax.servlet.http.Cookie;
 14 import javax.servlet.http.HttpServlet;
 15 import javax.servlet.http.HttpServletRequest;
 16 import javax.servlet.http.HttpServletResponse;
 17 import javax.servlet.http.HttpSession;
 18 
 19 import com.sun.corba.se.impl.encoding.CodeSetConversion.CTBConverter;
 20 import com.sun.org.apache.bcel.internal.generic.Select;
 21 
 22 import javafx.css.PseudoClass;
 23 
 24 public class Welcome extends HttpServlet {
 25 
 26     public void doGet(HttpServletRequest req, HttpServletResponse res) {
 27 
 28         try {
 29             req.setCharacterEncoding("gbk");
 30             res.setContentType("text/html;charset=gbk");
 31             HttpSession hs = req.getSession(true);
 32             String val = (String) hs.getAttribute("pass");
 33             String sessionId = hs.getId();
 34             String name = "";
 35             String passwd = "";
 36             if (val == null) {
 37                 // 如果Session中没有用户信息，再看看有没有Cookie信息
 38                 // 从客户端读取Cookie信息
 39                 Cookie[] allCookies = req.getCookies();
 40                 int i = 0;
 41                 // 如果allCookies不为空
 42                 if (allCookies != null) {
 43                     // 从中取出Cookie
 44                     for (i = 0; i < allCookies.length; i++) {
 45                         // 依次取出Cookie
 46                         Cookie tempCookie = allCookies[i];
 47                         if (tempCookie.getName().equals("myname")) {
 48                             name = tempCookie.getValue();
 49                         } else if (tempCookie.getName().equals("mypass")) {
 50                             passwd = tempCookie.getValue();
 51                         }
 52                     }
 53                     if (!name.equals("") && !passwd.equals("")) {
 54 
 55                         // System.out.println("准备跳转logincl页面，username="+name+",password="+passwd);
 56                         res.sendRedirect("logincl?username=" + name + "&password=" + passwd);
 57                     }
 58                 }
 59             }
 60 
 61             //res.sendRedirect("login?info=error1");
 62             String u = req.getParameter("uname");
 63             String p = req.getParameter("upassw");
 64             String s = req.getParameter("sx");
 65 
 66             PrintWriter pw = res.getWriter();
 67             pw.println("<body><center>");
 68             pw.println("<img src=imgs/521.jpg><br>");
 69             pw.println("welcom to my world,u=" + u + ",p=" + p + ",s=" + s + ",sessionId=" + sessionId);
 70 
 71             // ------------------开始分页--------------------
 72             int pageSize = 3;
 73             int pageNow = 1;
 74             String sPageNow = req.getParameter("pageNow");
 75             if (sPageNow != null) {
 76                 pageNow = Integer.parseInt(sPageNow);
 77             }
 78 
 79             // 调用分页函数
 80             UserBeanCl ubc = new UserBeanCl();
 81             ArrayList arrayList = ubc.getResultByPage(pageNow, pageSize);
 82 
 83             // 显示结果
 84             // 显示表头
 85             pw.println("<table border=1>");
 86             pw.println("<tr><th>id</th><th>username</th><th>password</th></tr>");
 87             for (int i = 0; i < arrayList.size(); i++) {
 88                 UserBean ub = (UserBean) arrayList.get(i);
 89                 pw.println("<tr>");
 90                 pw.println("<td>" + ub.getUserId() + "</td>");
 91                 pw.println("<td>" + ub.getUserName() + "</td>");
 92                 pw.print("<td>" + ub.getPassWord() + "</td>");
 93                 pw.println("</tr>");
 94             }
 95             pw.println("</table>");
 96             // 显示上一页
 97             if (pageNow != 1) {
 98                 pw.println("<a href=welcome?pageNow=" + (pageNow - 1) + ">" + "上一页</a>");
 99             }
100 
101             // 显示超链接
102             for (int i = pageNow; i <= ubc.getPageCount(); i++) {
103                 pw.println("<a href=welcome?pageNow=" + i + ">" + i + "</a>");
104             }
105             if (pageNow != ubc.getPageCount()) {
106                 pw.println("<a href=welcome?pageNow=" + (pageNow + 1) + ">" + "下一页</a>");
107             }
108             pw.println("</center></body>");
109         } catch (Exception e) {
110             // TODO: handle exception
111             e.printStackTrace();
112         }
113 
114     }
115 
116     public void doPost(HttpServletRequest req, HttpServletResponse res) {
117         this.doGet(req, res);
118     }
119 
120 }

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原文地址：https://www.cnblogs.com/buxingzhelyd/p/7376388.html