说真的，第一次看到MVC时候的感觉就和看到面向对象编程一样，感觉很方。之后慢慢的写了一些代码，在理解面向对象编程的同时也看到了MVC，虽然现在还是用不到，但是我觉得还是有些了解的好。
先谈谈MVC：模型(model)：程序员编写程序应有的功能（实现算法等等）、数据库专家进行数据管理和数据库设计(可以实现具体的功能)。
视图(view)：设计界面。
控制(Controller)：处理事务。
很多地方可能我理解的不是很到位。只是能写出来一个大概，后续我还会更新。又重新查了一遍资料，感觉又开始有一种模糊的感觉，不理解什么是MVC了。先写，之后再修改。
一共写了四个包，dao(用来处理数据库操作的各项)，model(创建了一个模型user)，util(工具包，连接数据库和关闭连接)，view(界面设计)。
我们先新建一个数据库：db_login，然后在数据库下添加一个表，叫做user。
就是这么一个样子。
然后我们去设计一下model下的user类：和数据库中的一一对应，id(int)，userName(String)，password(String)。
1 package com.rookie.model;
2
3 public class User {
4 private int id;
5 private String userName;
6 private String password;
7
8 public User() {
9 super();
10 // TODO Auto-generated constructor stub
11 }
12
13 public User(String userName, String password) {
14 super();
15 this.userName = userName;
16 this.password = password;
17 }
18
19 public int getId() {
20 return id;
21 }
22
23 public void setId(int id) {
24 this.id = id;
25 }
26
27 public String getUserName() {
28 return userName;
29 }
30
31 public void setUserName(String userName) {
32 this.userName = userName;
33 }
34
35 public String getPassword() {
36 return password;
37 }
38
39 public void setPassword(String password) {
40 this.password = password;
41 }
42
43 }
model类写好之后我们就去写util包下的DbUtil类。我用的是MySQL数据库，所以先去官网下载了Jar包
，build-path导入包。然后开始写util中的控制包。
和正常的数据库连接一样。
1 package com.rookie.util;
2
3 import java.sql.Connection;
4 import java.sql.DriverManager;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7
8 public class DbUtil {
9
10 String dbUrl = "jdbc:mysql://localhost:3306/db_login";
11 String dbUser = "root";
12 String dbPass = "salin";
13 String driveName = "com.mysql.jdbc.Driver";
14
15 public Connection getCon()throws Exception {
16 Class.forName(driveName);
17 Connection con = DriverManager.getConnection(dbUrl,dbUser,dbPass);
18 return con;
19 }
20
21 public void closeCon(Connection con) {
22 if(con!=null) {
23 try {
24 con.close();
25 } catch (SQLException e) {
26 e.printStackTrace();
27 }
28 }
29 }
30 }
这里只写了创建连接和关闭连接，我把剩下的数据库增删改放在了Dao包下(很多地方说Dao包相当于MVC中的model)。
接下来的话我打算去设计View类，View分成了两部分，一部分是登陆界面，一部分是注册界面(小小的加深一下)。
整体界面就是这样，那些图标是在：http://www.easyicon.net 找的。值得一说的是注册账户哪里是一个标签，然后加入了鼠标点击监听(mouseClickedAction)，点击之后就会弹出一个注册界面：
没有很高大上的样子，就是为了能够多理解一下MVC。这个界面的设计还是使用了 WindowsBuilder 插件。很方便，而且也加入了自己的一些想法，比如鼠标进入编辑框后会把编辑框的边框变色，还有一些东西是在开发的时候才能找到。下面直接贴代码：
1 package com.rookie.view;
2
3 import java.awt.EventQueue;
4
5 import javax.swing.JFrame;
6 import javax.swing.JPanel;
7 import javax.swing.border.EmptyBorder;
8 import javax.swing.border.LineBorder;
9
10 import com.rookie.dao.UserDao;
11 import com.rookie.model.User;
12 import com.rookie.util.DbUtil;
13
14 import javax.swing.JLabel;
15 import javax.swing.JOptionPane;
16 import javax.swing.JTextField;
17 import javax.swing.JPasswordField;
18 import javax.swing.JButton;
19 import java.awt.event.ActionListener;
20 import java.sql.Connection;
21 import java.awt.event.ActionEvent;
22 import javax.swing.SwingConstants;
23 import java.awt.Font;
24 import java.awt.Toolkit;
25 import java.awt.Color;
26
27
28 import java.awt.event.MouseAdapter;
29 import java.awt.event.MouseEvent;
30 import javax.swing.ImageIcon;
31
32 public class UserLogin extends JFrame {
33 /**
34 * 用户登陆界面。
35 */
36 private static final long serialVersionUID = 1L;
37 private JPanel contentPane;
38 private JPasswordField text_password;
39 private JButton bt_login;
40 private JLabel l_Prompt;
41 private Connection con;
42 private DbUtil dbUtil;
43 private UserDao userDao;
44 private JLabel label_2;
45 private JTextField text_username;
46 private final int WINDOWWIDTH = 386;
47 private final int WINDOWHEIGH = 256;
48 /**
49 * Launch the application.
50 */
51 public static void main(String[] args) {
52 EventQueue.invokeLater(new Runnable() {
53 public void run() {
54 try {
55 UserLogin frame = new UserLogin();
56 frame.setVisible(true);
57 } catch (Exception e) {
58 e.printStackTrace();
59 }
60 }
61 });
62 }
63
64 /**
65 * Create the frame.
66 */
67 public UserLogin() {
68 setTitle("\u6B22\u8FCE\u767B\u9646");
69 setResizable(false);
70 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
71 contentPane = new JPanel();
72 contentPane.setLayout(null);
73 contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
74 setContentPane(contentPane);
75
76 JLabel label = new JLabel("\u7528\u6237\u540D\uFF1A");
77 label.setIcon(new ImageIcon(UserLogin.class.getResource("/icon/user.png")));
78 label.setFont(new Font("黑体", Font.PLAIN, 12));
79 label.setBounds(60, 66, 68, 27);
80 contentPane.add(label);
81
82 JLabel label_1 = new JLabel("\u5BC6 \u7801\uFF1A");
83 label_1.setIcon(new ImageIcon(UserLogin.class.getResource("/icon/pass.png")));
84 label_1.setFont(new Font("黑体", Font.PLAIN, 12));
85 label_1.setBounds(60, 103, 68, 27);
86 contentPane.add(label_1);
87
88 text_password = new JPasswordField();
89 text_password.addMouseListener(new MouseAdapter() {
90 @Override
91 public void mouseExited(MouseEvent e) {
92 mouseExitedAction(e);
93 }
94 @Override
95 public void mouseEntered(MouseEvent e) {
96 mouseEnteredAction(e);
97 }
98 });
99 text_password.setBounds(138, 106, 124, 21);
100 contentPane.add(text_password);
101
102 bt_login = new JButton("\u767B\u9646");
103 bt_login.setIcon(new ImageIcon(UserLogin.class.getResource("/icon/Login.png")));
104 bt_login.addActionListener(new ActionListener() {
105 public void actionPerformed(ActionEvent e) {
106 loginAction(e);
107 }
108 });
109 bt_login.setBounds(138, 160, 91, 40);
110 contentPane.add(bt_login);
111
112 l_Prompt = new JLabel("");
113 l_Prompt.setForeground(Color.RED);
114 l_Prompt.setFont(new Font("黑体", Font.PLAIN, 13));
115 l_Prompt.setHorizontalAlignment(SwingConstants.CENTER);
116 l_Prompt.setBounds(10, 29, 360, 27);
117 contentPane.add(l_Prompt);
118
119 label_2 = new JLabel("\u6CE8\u518C\u8D26\u6237");
120 label_2.addMouseListener(new MouseAdapter() {
121 @Override
122 public void mouseClicked(MouseEvent e) {
123 new RegistUser().setVisible(true);;
124 }
125 @Override
126 public void mouseEntered(MouseEvent e) {
127 new RegistUser();
128 }
129 });
130 label_2.setForeground(Color.BLUE);
131 label_2.setBounds(284, 66, 53, 27);
132 contentPane.add(label_2);
133
134 text_username = new JTextField();
135 text_username.addMouseListener(new MouseAdapter() {
136 @Override
137 public void mouseEntered(MouseEvent e) {
138 mouseEnteredAction(e);
139 }
140 @Override
141 public void mouseExited(MouseEvent e) {
142 mouseExitedAction(e);
143 }
144 });
145 text_username.setBounds(138, 69, 124, 21);
146 contentPane.add(text_username);
147 text_username.setBorder(new LineBorder(new Color(0,0,0),1,false));
148 text_password.setBorder(new LineBorder(new Color(0,0,0),1,false));
149 text_username.setColumns(10);
150
151 int width = Toolkit.getDefaultToolkit().getScreenSize().width;
152 int heigh = Toolkit.getDefaultToolkit().getScreenSize().height;
153 int x = (width-WINDOWWIDTH)/2;
154 int y = (heigh-WINDOWHEIGH)/2;
155 this.setBounds(x, y, WINDOWWIDTH, WINDOWHEIGH);
156 }
157 //鼠标进入编辑框事件
158 private void mouseExitedAction(MouseEvent e) {
159 // TODO Auto-generated method stub
160 JTextField text = (JTextField)e.getSource();
161 text.setBorder(new LineBorder(new Color(0,0,0),1,false));
162 }
163 //鼠标退出编辑框事件
164 private void mouseEnteredAction(MouseEvent e) {
165 // TODO Auto-generated method stub
166 JTextField text = (JTextField)e.getSource();
167 text.setBorder(new LineBorder(new Color(0,0,255),1,false));
168 }
169
170 private void loginAction(ActionEvent e) {
171 User user = new User();
172 String userName = text_username.getText();
173 char[] pass = text_password.getPassword();
174 String password = String.valueOf(pass);
175 if(userName == null || userName.equals("")) {
176 l_Prompt.setText("用户名不能为空！");
177 return ;
178 }else if(password == null || password.equals("")){
179 l_Prompt.setText("密码不能为空！");
180 return ;
181 }
182 user.setUserName(userName);
183 user.setPassword(password);
184 try {
185 dbUtil = new DbUtil();
186 userDao = new UserDao();
187 con = dbUtil.getCon();
188 User loginUser = userDao.login(con, user);
189 if( loginUser != null ) {
190 l_Prompt.setText("登陆成功，欢迎使用！");
191 }else {
192 l_Prompt.setText("用户名或密码错误！");
193 }
194 } catch (Exception e1) {
195 dbUtil.closeCon(con);
196 } finally {
197 dbUtil.closeCon(con);
198 }
199 }
200 }
UserLogin
1 package com.rookie.view;
2
3
4 import javax.swing.JButton;
5 import javax.swing.JDialog;
6 import javax.swing.JPasswordField;
7
8 import com.rookie.dao.RegisDao;
9 import com.rookie.dao.UserDao;
10 import com.rookie.model.User;
11 import com.rookie.util.DbUtil;
12
13 import javax.swing.JLabel;
14 import javax.swing.JTextField;
15 import java.awt.event.ActionListener;
16 import java.sql.Connection;
17 import java.awt.Toolkit;
18 import java.awt.event.ActionEvent;
19 import javax.swing.SwingConstants;
20 import java.awt.Color;
21 import javax.swing.ImageIcon;
22
23 public class RegistUser extends JDialog {
24 private Connection con;
25 private DbUtil dbUtil;
26 private RegisDao regisDao;
27 private JTextField text_userName;
28 private JPasswordField text_password;
29 private JPasswordField text_repeat;
30 private JLabel prompt;
31 private final int WINDOWWIDTH = 296;
32 private final int WINDOWHEIGH = 300;
33
34 /**
35 * Launch the application.
36 */
37 public static void main(String[] args) {
38 try {
39 RegistUser dialog = new RegistUser();
40 dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
41 dialog.setVisible(true);
42 } catch (Exception e) {
43 e.printStackTrace();
44 }
45 }
46
47 /**
48 * Create the dialog.
49 */
50 public RegistUser() {
51 getContentPane().setForeground(Color.RED);
52 setTitle("\u7528\u6237\u6CE8\u518C");
53 setAlwaysOnTop(true);
54 getContentPane().setLayout(null);
55
56 JLabel label = new JLabel("*\u7528\u6237\u540D\uFF1A");
57 label.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/user.png")));
58 label.setBounds(36, 42, 77, 18);
59 getContentPane().add(label);
60
61 JLabel label_1 = new JLabel("*\u5BC6 \u7801\uFF1A");
62 label_1.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/pass.png")));
63 label_1.setBounds(36, 80, 77, 15);
64 getContentPane().add(label_1);
65
66 text_userName = new JTextField();
67 text_userName.setBounds(123, 42, 113, 21);
68 getContentPane().add(text_userName);
69 text_userName.setColumns(10);
70
71 text_password = new JPasswordField();
72 text_password.setEchoChar(‘*‘);
73 text_password.setColumns(10);
74 text_password.setBounds(123, 77, 113, 21);
75 getContentPane().add(text_password);
76
77 JLabel label_2 = new JLabel("*\u91CD\u590D\u5BC6\u7801\uFF1A");
78 label_2.setBounds(47, 122, 77, 15);
79 getContentPane().add(label_2);
80
81 text_repeat = new JPasswordField();
82 text_repeat.setEchoChar(‘*‘);
83 text_repeat.setColumns(10);
84 text_repeat.setBounds(123, 119, 113, 21);
85 getContentPane().add(text_repeat);
86
87 JButton button = new JButton("");
88 button.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/Register.png")));
89 button.addActionListener(new ActionListener() {
90 public void actionPerformed(ActionEvent e) {
91 addUserAction(e);
92 }
93 });
94 button.setBounds(36, 185, 77, 33);
95 getContentPane().add(button);
96
97 JButton button_1 = new JButton("");
98 button_1.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/reset.png")));
99 button_1.addActionListener(new ActionListener() {
100 public void actionPerformed(ActionEvent e) {
101 text_password.setText("");
102 text_repeat.setText("");
103 text_userName.setText("");
104 prompt.setText("");
105 }
106 });
107 button_1.setBounds(165, 185, 71, 33);
108 getContentPane().add(button_1);
109
110 prompt = new JLabel("");
111 prompt.setForeground(Color.RED);
112 prompt.setHorizontalAlignment(SwingConstants.CENTER);
113 prompt.setBounds(36, 160, 200, 15);
114 getContentPane().add(prompt);
115
116 int width = Toolkit.getDefaultToolkit().getScreenSize().width;
117 int heigh = Toolkit.getDefaultToolkit().getScreenSize().height;
118 int x = (width-WINDOWWIDTH)/2;
119 int y = (heigh-WINDOWHEIGH)/2;
120 this.setBounds(x, y, 286, 278);
121 }
122
123 protected void addUserAction(ActionEvent e) {
124 // TODO Auto-generated method stub
125 String userName = text_userName.getText();
126 char []pass = text_password.getPassword();
127 String password = String.valueOf(pass);
128 char []rep = text_repeat.getPassword();
129 String repeat = String.valueOf(rep);
130 if(userName.length() < 6) {
131 prompt.setText("用户名长度错误！");
132 return ;
133 }else if( !password.equals(repeat) || (password.length() < 6 || password.length() > 20)){
134 prompt.setText("密码存在问题！");
135 return ;
136 }
137 User user = new User(userName, password);
138 dbUtil = new DbUtil();
139 regisDao = new RegisDao();
140 try {
141 con = dbUtil.getCon();
142 boolean hasUser= regisDao.hasUser(con, user);
143 if( hasUser == false) {
144 regisDao.addUser(con, user);
145 prompt.setText("添加成功!");
146 }else {
147 prompt.setText("用户名已存在!");
148 }
149 } catch (Exception e1) {
150 // TODO Auto-generated catch block
151 e1.printStackTrace();
152 } finally {
153 dbUtil.closeCon(con);
154 }
155 }
156
157 }
RegistUser
写完界面之后就是Dao类了，用来处理数据库事件，我也写了两个对应上面的View界面，一个是登陆，一个是注册。用了MySQL语句，并不是很难。
1 package com.rookie.view;
2
3
4 import javax.swing.JButton;
5 import javax.swing.JDialog;
6 import javax.swing.JPasswordField;
7
8 import com.rookie.dao.RegisDao;
9 import com.rookie.dao.LoginDao;
10 import com.rookie.model.User;
11 import com.rookie.util.DbUtil;
12
13 import javax.swing.JLabel;
14 import javax.swing.JTextField;
15 import java.awt.event.ActionListener;
16 import java.sql.Connection;
17 import java.awt.Toolkit;
18 import java.awt.event.ActionEvent;
19 import javax.swing.SwingConstants;
20 import java.awt.Color;
21 import javax.swing.ImageIcon;
22
23 public class RegistUser extends JDialog {
24 private Connection con;
25 private DbUtil dbUtil;
26 private RegisDao regisDao;
27 private JTextField text_userName;
28 private JPasswordField text_password;
29 private JPasswordField text_repeat;
30 private JLabel prompt;
31 private final int WINDOWWIDTH = 296;
32 private final int WINDOWHEIGH = 300;
33
34 /**
35 * Launch the application.
36 */
37 public static void main(String[] args) {
38 try {
39 RegistUser dialog = new RegistUser();
40 dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
41 dialog.setVisible(true);
42 } catch (Exception e) {
43 e.printStackTrace();
44 }
45 }
46
47 /**
48 * Create the dialog.
49 */
50 public RegistUser() {
51 getContentPane().setForeground(Color.RED);
52 setTitle("\u7528\u6237\u6CE8\u518C");
53 setAlwaysOnTop(true);
54 getContentPane().setLayout(null);
55
56 JLabel label = new JLabel("*\u7528\u6237\u540D\uFF1A");
57 label.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/user.png")));
58 label.setBounds(36, 42, 77, 18);
59 getContentPane().add(label);
60
61 JLabel label_1 = new JLabel("*\u5BC6 \u7801\uFF1A");
62 label_1.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/pass.png")));
63 label_1.setBounds(36, 80, 77, 15);
64 getContentPane().add(label_1);
65
66 text_userName = new JTextField();
67 text_userName.setBounds(123, 42, 113, 21);
68 getContentPane().add(text_userName);
69 text_userName.setColumns(10);
70
71 text_password = new JPasswordField();
72 text_password.setEchoChar(‘*‘);
73 text_password.setColumns(10);
74 text_password.setBounds(123, 77, 113, 21);
75 getContentPane().add(text_password);
76
77 JLabel label_2 = new JLabel("*\u91CD\u590D\u5BC6\u7801\uFF1A");
78 label_2.setBounds(47, 122, 77, 15);
79 getContentPane().add(label_2);
80
81 text_repeat = new JPasswordField();
82 text_repeat.setEchoChar(‘*‘);
83 text_repeat.setColumns(10);
84 text_repeat.setBounds(123, 119, 113, 21);
85 getContentPane().add(text_repeat);
86
87 JButton button = new JButton("");
88 button.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/Register.png")));
89 button.addActionListener(new ActionListener() {
90 public void actionPerformed(ActionEvent e) {
91 addUserAction(e);
92 }
93 });
94 button.setBounds(36, 185, 77, 33);
95 getContentPane().add(button);
96
97 JButton button_1 = new JButton("");
98 button_1.setIcon(new ImageIcon(RegistUser.class.getResource("/icon/reset.png")));
99 button_1.addActionListener(new ActionListener() {
100 public void actionPerformed(ActionEvent e) {
101 text_password.setText("");
102 text_repeat.setText("");
103 text_userName.setText("");
104 prompt.setText("");
105 }
106 });
107 button_1.setBounds(165, 185, 71, 33);
108 getContentPane().add(button_1);
109
110 prompt = new JLabel("");
111 prompt.setForeground(Color.RED);
112 prompt.setHorizontalAlignment(SwingConstants.CENTER);
113 prompt.setBounds(36, 160, 200, 15);
114 getContentPane().add(prompt);
115
116 int width = Toolkit.getDefaultToolkit().getScreenSize().width;
117 int heigh = Toolkit.getDefaultToolkit().getScreenSize().height;
118 int x = (width-WINDOWWIDTH)/2;
119 int y = (heigh-WINDOWHEIGH)/2;
120 this.setBounds(x, y, 286, 278);
121 }
122
123 protected void addUserAction(ActionEvent e) {
124 // TODO Auto-generated method stub
125 String userName = text_userName.getText();
126 char []pass = text_password.getPassword();
127 String password = String.valueOf(pass);
128 char []rep = text_repeat.getPassword();
129 String repeat = String.valueOf(rep);
130 if(userName.length() < 6) {
131 prompt.setText("用户名长度错误！");
132 return ;
133 }else if( !password.equals(repeat) || (password.length() < 6 || password.length() > 20)){
134 prompt.setText("密码存在问题！");
135 return ;
136 }
137 User user = new User(userName, password);
138 dbUtil = new DbUtil();
139 regisDao = new RegisDao();
140 try {
141 con = dbUtil.getCon();
142 boolean hasUser= regisDao.hasUser(con, user);
143 if( hasUser == false) {
144 regisDao.addUser(con, user);
145 prompt.setText("添加成功!");
146 }else {
147 prompt.setText("用户名已存在!");
148 }
149 } catch (Exception e1) {
150 // TODO Auto-generated catch block
151 e1.printStackTrace();
152 } finally {
153 dbUtil.closeCon(con);
154 }
155 }
156
157 }
LoginDao
1 package com.rookie.dao;
2
3 import java.sql.Connection;
4 import java.sql.PreparedStatement;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7
8 import com.rookie.model.User;
9
10 public class RegisDao {
11
12 public RegisDao() {
13 super();
14 // TODO Auto-generated constructor stub
15 }
16
17 public boolean hasUser(Connection con,User user) throws SQLException {
18 String sql = "select * from user where userName=?";
19 PreparedStatement pra = con.prepareStatement(sql);
20 pra.setString(1, user.getUserName());
21 ResultSet result = pra.executeQuery();
22 if(result.next()) {
23 String userName = result.getString("userName");
24 if(userName.equals(user.getUserName())) {
25 return true;
26 }else {
27 return false;
28 }
29 }else {
30 return false;
31 }
32 }
33
34 //添加用户
35 public int addUser(Connection con,User user) throws SQLException {
36 String sql = "insert into user(userName,password) values(?,?)";
37 PreparedStatement pra = con.prepareStatement(sql);
38 pra.setString(1, user.getUserName());
39 pra.setString(2, user.getPassword());
40 int resultNum = pra.executeUpdate();
41 pra.close();
42 return resultNum;
43 }
44
45
46
47 }
RegisDao
学艺不精，还望多多指教。目前看来，MVC是将整个软件开发过程分成了三个部分而不是三个包，Model很多地方写着是数据库的处理，我是用Dao来代替，而把model写成了模型。
(图片来自网络)一种映射机制，并没有强制去规定哪个地方去写什么，就我目前而言，我更喜欢去在model封装数据库所对应的类。而控制层和view层是紧密联系的，甚至很多代码是无法独立出来的。
新手上路，请多包涵。
代码已经打包上传：链接：http://pan.baidu.com/s/1geDNPWR 密码：b6e0
时间： 2024-10-26 10:22:19