总结学了 j2ee 一月半后的项目情况(3)

源码：

1、用户 CRUD servlet

 1 package fafa.shop.controller;
 2 import java.io.IOException;
 3 import java.util.ArrayList;
 4 import javax.servlet.ServletException;
 5 import javax.servlet.http.HttpServlet;
 6 import javax.servlet.http.HttpServletRequest;
 7 import javax.servlet.http.HttpServletResponse;
 8 import fafa.shop.service.User;
 9 import fafa.shop.service.UserModel;
10 @SuppressWarnings("serial")
11 public class UserServ extends HttpServlet {
12     public void doGet(HttpServletRequest request, HttpServletResponse response)
13             throws ServletException, IOException {
14         request.setCharacterEncoding("GBK") ;
15             UserModel us = new UserModel() ;        
16         String type= request.getParameter("type");
17         if (type.equals("add")){
18             String uid = null ; 
19             String username = request.getParameter("username") ;
20             String password = request.getParameter("password") ;
21             String email = request.getParameter("email") ;
22             User user = new User(uid, username, password, email) ;
23             if (us.insertUser(user)){
24                 ArrayList<User> all = us.getAll() ;
25                 request.setAttribute("user", all) ;
26                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
27             }else{
28                 request.setAttribute("error", "用户添加失败") ;
29                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
30             }
31         }else if (type.equals("mod")){
32             String uid = request.getParameter("uid") ;
33             ArrayList<User> all = us.getOne(uid) ;
34             if (all != null){
35                 request.setAttribute("user", all) ;
36                 request.getRequestDispatcher("/WEB-INF/update.jsp").forward(request, response) ;
37             }else {
38                 request.setAttribute("error", "用户不存在！！！") ;
39                 request.getRequestDispatcher("/WEB-INF/update.jsp").forward(request, response) ;
40             }
41 
42         }else if (type.equals("update")){
43             String uid = request.getParameter("uid") ;
44             String username = request.getParameter("username") ;
45             String password = request.getParameter("password") ;
46             String email = request.getParameter("email") ;
47             User user = new User(uid, username, password, email) ;
48             if (us.updateUser(user)){
49                 request.setAttribute("updateSuccess", "数据更新成功！") ;
50                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
51             }else{
52                 request.setAttribute("updateError", "数据更新失败！") ;
53                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
54             }
55         }else if (type.equals("del")){
56             String uid = request.getParameter("uid") ;
57             
58             if (us.delUser(uid)){
59                 request.setAttribute("delSuccess", "数据删除成功！") ;
60                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
61             }else{
62                 request.setAttribute("delError", "数据删除失败！") ;
63                 request.getRequestDispatcher("/index.jsp").forward(request, response) ;
64             }
65         }
66         
67     }
68     public void doPost(HttpServletRequest request, HttpServletResponse response)
69             throws ServletException, IOException {
70         this.doGet(request, response) ;
71     }
72 
73 }

2、user bean 类

 1 package fafa.shop.service;
 2 
 3 public class User {
 4     private String uid ;
 5     private String username ;
 6     private String password ;
 7     private String email ;
 8     
 9     public User() {
10         super();
11     }
12     public User(String uid ,String username, String password, String email) {
13         super();
14         this.uid = uid ;
15         this.username = username;
16         this.password = password;
17         this.email = email;
18     }
19     public String getUid() {
20         return uid;
21     }
22     public void setUid(String uid) {
23         this.uid = uid;
24     }
25     public String getUsername() {
26         return username;
27     }
28     public void setUsername(String username) {
29         this.username = username;
30     }
31     public String getPassword() {
32         return password;
33     }
34     public void setPassword(String password) {
35         this.password = password;
36     }
37     public String getEmail() {
38         return email;
39     }
40     public void setEmail(String email) {
41         this.email = email;
42     }
43 }

3、userModel 类和数据库连接类

  1 package fafa.shop.service;
  2 
  3 import java.sql.*;
  4 import java.util.ArrayList;
  5 
  6 import fafa.shop.util.DBUtil;
  7 
  8 public class UserModel {
  9     private Connection conn = null ;
 10     private PreparedStatement ps = null ;
 11     private ResultSet rs = null ;
 12     
 13     //插入用户
 14     public boolean insertUser(User user){
 15         boolean flag = false ;
 16         try {
 17             this.conn = DBUtil.getConnection() ;
 18             String sql = "INSERT INTO user(uid,username,password,email) VALUES(?,?,?,?)" ;
 19             this.ps = this.conn.prepareStatement(sql) ;
 20             this.ps.setString(1, null) ;
 21             this.ps.setString(2, user.getUsername()) ;
 22             this.ps.setString(3, user.getPassword()) ;
 23             this.ps.setString(4, user.getEmail()) ;
 24             this.ps.executeUpdate() ;
 25             flag = true ;
 26         } catch (Exception e) {
 27             e.printStackTrace();
 28         }finally{
 29             try {
 30                 this.conn.close() ;
 31             } catch (SQLException e) {
 32                 e.printStackTrace();
 33             }
 34             try {
 35                 this.ps.close();
 36             } catch (SQLException e) {
 37                 e.printStackTrace();
 38             } 
 39         }
 40         
 41         return flag ;
 42     }
 43     
 44     //取得所有用户
 45     public ArrayList<User> getAll(){
 46         ArrayList<User> all = new ArrayList<User>() ;
 47         try {
 48             this.conn = DBUtil.getConnection() ;
 49             String sql = "SELECT uid, username, password, email FROM user" ;
 50             this.ps = this.conn.prepareStatement(sql) ;
 51             this.rs = this.ps.executeQuery() ;
 52             while(this.rs.next()){
 53                 User user = new User() ;
 54                 user.setUid(rs.getString("uid")) ;
 55                 user.setUsername(rs.getString("username")) ;
 56                 user.setPassword(rs.getString("password")) ;
 57                 user.setEmail(rs.getString("email")) ;
 58                 all.add(user) ;
 59             }
 60             
 61         } catch (Exception e) {
 62             e.printStackTrace();
 63         }finally{
 64             try {
 65                 this.conn.close() ;
 66                 this.ps.close() ;
 67                 this.rs.close() ;
 68             } catch (SQLException e) {
 69                 e.printStackTrace();
 70             }
 71         }
 72 
 73         return all ;
 74     }
 75     
 76     //取一条数据
 77     public ArrayList<User> getOne(String uid){
 78         ArrayList<User> all = new ArrayList<User>() ;
 79         try {
 80             this.conn = DBUtil.getConnection() ;
 81             String sql = "SELECT uid, username, password, email FROM user WHERE uid=?" ;
 82             this.ps = this.conn.prepareStatement(sql) ;
 83             this.ps.setString(1, uid) ;
 84             this.rs = this.ps.executeQuery() ;
 85             while(this.rs.next()){
 86                 User user = new User() ;
 87                 user.setUid(rs.getString("uid")) ;
 88                 user.setUsername(rs.getString("username")) ;
 89                 user.setPassword(rs.getString("password")) ;
 90                 user.setEmail(rs.getString("email")) ;
 91                 all.add(user) ;
 92             }
 93             
 94         } catch (Exception e) {
 95             e.printStackTrace();
 96         }finally{
 97             try {
 98                 this.conn.close() ;
 99                 this.ps.close() ;
100                 this.rs.close() ;
101             } catch (SQLException e) {
102                 e.printStackTrace();
103             }
104         }
105         return all ;
106     }
107     
108     //更新数据
109     public boolean updateUser(User user){
110         boolean flag = false ;
111         try {
112             this.conn = DBUtil.getConnection() ;
113             String sql = "UPDATE user SET username=?, password=?, email=? WHERE uid=?" ;
114             this.ps = this.conn.prepareStatement(sql) ;
115             this.ps.setString(1, user.getUsername()) ;
116             this.ps.setString(2, user.getPassword()) ;
117             this.ps.setString(3, user.getEmail()) ;
118             this.ps.setString(4, user.getUid()) ;
119             this.ps.executeUpdate() ;
120             flag = true ;
121         } catch (Exception e) {
122             e.printStackTrace();
123         }finally{
124             try {
125                 this.conn.close() ;
126             } catch (SQLException e) {
127                 e.printStackTrace();
128             }
129             try {
130                 this.ps.close();
131             } catch (SQLException e) {
132                 e.printStackTrace();
133             } 
134         }
135         return flag ;
136     }
137     
138     //删除用户
139     public boolean delUser(String uid){
140         boolean flag = false ;
141         try {
142             this.conn = DBUtil.getConnection() ;
143             String sql = "DELETE FROM user WHERE uid=?" ;
144             this.ps = this.conn.prepareStatement(sql) ;
145             this.ps.setInt(1, Integer.parseInt(uid)) ;
146             this.ps.executeUpdate() ;
147             flag = true ;
148         } catch (Exception e) {
149             e.printStackTrace();
150         }finally{
151             try {
152                 this.conn.close() ;
153             } catch (SQLException e) {
154                 e.printStackTrace();
155             }
156             try {
157                 this.ps.close();
158             } catch (SQLException e) {
159                 e.printStackTrace();
160             } 
161         }
162         return flag ;
163     }
164 }

 1 package fafa.shop.util;
 2 
 3 import java.sql.*;
 4 
 5 public class DBUtil {
 6     private static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;
 7     private static final String DBURL = "jdbc:mysql://localhost:3306/test" ;
 8     private static final String DBUSER = "root" ;
 9     private static final String DBPASS = "123456" ;
10     
11     private static Connection conn = null ;
12     
13     //外部取得连接
14     public static Connection getConnection() throws Exception {
15         Class.forName(DBDRIVER) ;
16         conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS) ;
17         return conn ;
18     }
19     
20     //关闭连接
21     public static void close(ResultSet rs, Statement ps, Connection ct){
22         try {
23             if (rs!=null){
24                 rs.close() ;
25             }
26         } catch (SQLException e) {
27             e.printStackTrace();
28         }
29         try {
30             if (ps!=null){
31                 ps.close() ;
32             }
33         } catch (SQLException e) {
34             e.printStackTrace();
35         }
36         try {
37             if (ct!=null){
38                 ct.close() ;
39             }
40         } catch (SQLException e) {
41             e.printStackTrace();
42         }
43     }
44 }

这样就完成成了数据的CRUD ，我现在是初学者啊，没办法只能这样练练手，希望能更快上手.

本来是使用三种数据库 oracle、mssql 、mysql 完成的。

以上还少了功能：分页、上传文件、支付、等等。

当然现在很多企业也不再会这样写代码了，基本都是用框架了。所以下面的学习中心转移到框架和基础加深了。