1.概述
一个简单的swing登录界面,使用了简单的JDBC. 如图:
2.UI
(1)主界面
主界面使用了3_1网格布局+三个JPanel,中间的JPanel使用了2_2网格布局:
1import java.awt.FlowLayout; 2import java.awt.Font; 3import java.awt.GridLayout; 4import java.util.Enumeration; 5import java.awt.Container; 6 7import javax.swing.JButton; 8import javax.swing.JFrame; 9import javax.swing.JLabel; 10import javax.swing.JOptionPane; 11import javax.swing.JPanel; 12import javax.swing.JPasswordField; 13import javax.swing.JTextField; 14import javax.swing.UIManager; 15import javax.swing.plaf.FontUIResource; 16 17public class UserManagement 18{ 19 private JFrame mainFrame = new JFrame("登录"); 20 private Container container = mainFrame.getContentPane(); 21 private JLabel titleLabel = new JLabel("登录/注册", JLabel.CENTER); 22 23 private JPanel inputField = new JPanel(); 24 private JLabel usernameLabel = new JLabel("用户名:", JLabel.CENTER); 25 private JTextField username = new JTextField(); 26 private JLabel passwordLabel = new JLabel("密码:", JLabel.CENTER); 27 private JPasswordField password = new JPasswordField(); 28 29 private JPanel buttonField = new JPanel(); 30 private JButton save = new JButton("登录/注册"); 31 private JButton cancel = new JButton("取消"); 32 33 public UserManagement() 34 { 35 init(); 36 setFont(new Font("微软雅黑",Font.PLAIN,14)); 37 addEvent(); 38 } 39 40 private void init() 41 { 42 container.setLayout(new GridLayout(3, 1, 0, 10)); 43 container.add(titleLabel); 44 45 inputField.setLayout(new GridLayout(2, 2, 5, 5)); 46 inputField.add(usernameLabel); 47 inputField.add(username); 48 inputField.add(passwordLabel); 49 inputField.add(password); 50 container.add(inputField); 51 52 buttonField.setLayout(new FlowLayout(FlowLayout.CENTER,20,0)); 53 buttonField.add(save); 54 buttonField.add(cancel); 55 container.add(buttonField); 56 57 mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 58 mainFrame.setSize(300, 200); 59 mainFrame.setLocationRelativeTo(null); 60 mainFrame.setVisible(true); 61 } 62 63 private void setFont(Font font) 64 { 65 FontUIResource fontRes = new FontUIResource(font); 66 for(Enumeration<Object> keys = UIManager.getDefaults().keys();keys.hasMoreElements();) 67 { 68 Object key = keys.nextElement(); 69 Object value = UIManager.get(key); 70 if(value instanceof FontUIResource) 71 UIManager.put(key, fontRes); 72 } 73 } 74 75 private void addEvent() 76 { 77 save.addActionListener( 78 e-> 79 { 80 User user = new User(); 81 user.setName(username.getText()); 82 user.setPassword(new String(password.getPassword())); 83 if(DBUtils.exists(user)) 84 new UserInformation(DBUtils.getByName(user.getName())); 85 else 86 JOptionPane.showConfirmDialog(null, 87 "添加"+(DBUtils.add(user) ? "成功" : "失败"), "",JOptionPane.CLOSED_OPTION); 88 } 89 ); 90 91 cancel.addActionListener( 92 e-> 93 { 94 mainFrame.dispose(); 95 } 96 ); 97 } 98 99 public static void main(String[] args) 100 { 101 new UserManagement(); 102 } 103}
重点说一下几行代码:
mainFrame.setLocationRelativeTo(null);
使整个JFrame处于屏幕水平居中与垂直居中位置.
1private void setFont(Font font) 2{ 3 FontUIResource fontRes = new FontUIResource(font); 4 for(Enumeration<Object> keys = UIManager.getDefaults().keys();keys.hasMoreElements();) 5 { 6 Object key = keys.nextElement(); 7 Object value = UIManager.get(key); 8 if(value instanceof FontUIResource) 9 UIManager.put(key, fontRes); 10 } 11}
设置所有组件的字体.
1cancel.addActionListener( 2 e-> 3 { 4 mainFrame.dispose(); 5 } 6);
按钮添加关闭窗口事件.
JOptionPane.showConfirmDialog(null,"添加"+(DBUtils.add(user) ? "成功" : "失败"), "",JOptionPane.CLOSED_OPTION);
提示信息框.
(2)用户信息界面
用户信息界面采用了3_1网格,同样3个JPanel,中间的JPanel布局为3_2网格.
1import java.awt.FlowLayout; 2import java.awt.Font; 3import java.awt.GridLayout; 4import java.util.Enumeration; 5import java.awt.Container; 6 7import javax.swing.JButton; 8import javax.swing.JFrame; 9import javax.swing.JLabel; 10import javax.swing.JOptionPane; 11import javax.swing.JPanel; 12import javax.swing.JPasswordField; 13import javax.swing.JTextField; 14import javax.swing.UIManager; 15import javax.swing.plaf.FontUIResource; 16 17public class UserInformation 18{ 19 private JFrame mainFrame = new JFrame("用户信息"); 20 private Container container = mainFrame.getContentPane(); 21 private JLabel titleLabel = new JLabel("用户信息", JLabel.CENTER); 22 23 private JPanel inputField = new JPanel(); 24 private JLabel idLabel = new JLabel("Id",JLabel.CENTER); 25 private JTextField id = new JTextField(); 26 private JLabel usernameLabel = new JLabel("Username", JLabel.CENTER); 27 private JTextField username = new JTextField(); 28 private JLabel passwordLabel = new JLabel("Password", JLabel.CENTER); 29 private JPasswordField password = new JPasswordField(); 30 31 private JPanel buttonField = new JPanel(); 32 private JButton update = new JButton("更新"); 33 private User user; 34 35 public UserInformation(User user) 36 { 37 if(user == null) 38 mainFrame.dispose(); 39 this.user = user; 40 init(); 41 setFont(new Font("微软雅黑", Font.PLAIN, 14)); 42 addEvent(); 43 } 44 45 private void init() 46 { 47 container.setLayout(new GridLayout(3,1,0,10)); 48 container.add(titleLabel); 49 50 inputField.setLayout(new GridLayout(3,2,0,3)); 51 inputField.add(idLabel); 52 inputField.add(id); 53 id.setText(user.getId()); 54 id.setEditable(false); 55 inputField.add(usernameLabel); 56 username.setText(user.getName()); 57 inputField.add(username); 58 inputField.add(passwordLabel); 59 password.setText(user.getPassword()); 60 inputField.add(password); 61 container.add(inputField); 62 63 buttonField.setLayout(new FlowLayout()); 64 buttonField.add(update); 65 container.add(buttonField); 66 67 mainFrame.setVisible(true); 68 mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 69 mainFrame.setLocationRelativeTo(null); 70 mainFrame.setSize(300,250); 71 } 72 73 private void setFont(Font font) 74 { 75 FontUIResource fontRes = new FontUIResource(font); 76 for (Enumeration<Object> keys = UIManager.getDefaults().keys(); keys.hasMoreElements();) 77 { 78 Object key = keys.nextElement(); 79 Object value = UIManager.get(key); 80 if (value instanceof FontUIResource) 81 UIManager.put(key, fontRes); 82 } 83 } 84 85 private void addEvent() 86 { 87 update.addActionListener( 88 e-> 89 { 90 user.setName(username.getText()); 91 user.setPassword(new String(password.getPassword())); 92 JOptionPane.showConfirmDialog(null, "更新"+(DBUtils.modify(user) ? "成功" : "失败"),"确认",JOptionPane.CLOSED_OPTION); 93 } 94 ); 95 } 96}
这个JFrame不能设置EXIT_ON_CLOSE.因为这不是"主窗体",不然的话点击关闭主窗体也没了.
mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
3.数据库操作
1import java.sql.Connection; 2import java.sql.DriverManager; 3import java.sql.PreparedStatement; 4import java.sql.ResultSet; 5import java.sql.SQLException; 6import java.util.UUID; 7 8public class DBUtils 9{ 10 private final static String driver = "com.mysql.cj.jdbc.Driver"; 11 private final static String username = "aa"; 12 private final static String password = "123456"; 13 private final static String url = "jdbc:mysql://127.0.0.1/user_test"; 14 private final static String insert = "insert into user(id,username,password) values(?,?,?)"; 15 private final static String update = "update user set username = ?,password = ? where id = ?"; 16 private final static String delete = "delete from user where id = ?"; 17 private final static String select = "select * from user where username = ?"; 18 19 private static Connection connection; 20 21 static 22 { 23 try 24 { 25 Class.forName(driver); 26 connection = DriverManager.getConnection(url,username,password); 27 } 28 catch(Exception e) 29 { 30 e.printStackTrace(); 31 connection = null; 32 } 33 } 34 35 public static boolean exists(User user) 36 { 37 try 38 { 39 PreparedStatement exist = connection.prepareStatement(select); 40 exist.setString(1,user.getName()); 41 ResultSet existResult = exist.executeQuery(); 42 return existResult.next(); 43 } 44 catch (SQLException e) 45 { 46 e.printStackTrace(); 47 return false; 48 } 49 } 50 51 public static boolean add(User user) 52 { 53 try 54 { 55 PreparedStatement add = connection.prepareStatement(insert); 56 user.setId(UUID.randomUUID().toString().substring(0, 8)); 57 add.setString(1, user.getId()); 58 add.setString(2, user.getName()); 59 add.setString(3, user.getPassword()); 60 return add.executeUpdate() == 1; 61 } 62 catch (SQLException e) 63 { 64 e.printStackTrace(); 65 return false; 66 } 67 } 68 69 public static boolean modify(User user) 70 { 71 try 72 { 73 PreparedStatement modify = connection.prepareStatement(update); 74 System.out.println(user.getName()); 75 modify.setString(1, user.getName()); 76 modify.setString(2, user.getPassword()); 77 modify.setString(3, user.getId()); 78 return modify.executeUpdate() == 1; 79 } 80 catch (SQLException e) 81 { 82 e.printStackTrace(); 83 return false; 84 } 85 } 86 87 public static boolean delete(User user) 88 { 89 if(exists(user)) 90 { 91 try 92 { 93 PreparedStatement del = connection.prepareStatement(delete); 94 del.setString(1, user.getId()); 95 return del.executeUpdate() == 1; 96 } 97 catch (SQLException e) 98 { 99 e.printStackTrace(); 100 } 101 } 102 return false; 103 } 104 105 public static User getByName(String name) 106 { 107 try 108 { 109 PreparedStatement exist = connection.prepareStatement(select); 110 exist.setString(1, name); 111 ResultSet existResult = exist.executeQuery(); 112 if(existResult.next()) 113 { 114 User user = new User(); 115 user.setId(existResult.getString("id")); 116 user.setName(existResult.getString("username")); 117 user.setPassword(existResult.getString("password")); 118 return user; 119 } 120 return null; 121 } 122 catch (SQLException e) 123 { 124 e.printStackTrace(); 125 return null; 126 } 127 } 128}
注册驱动后,增删查改,就是注意一下mysql版本与驱动名对应.