用java写一个登录界面
时间: 2023-06-15 14:03:43 浏览: 36
下面是一个简单的 Java 登录界面的示例代码:
```java
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class LoginFrame extends JFrame implements ActionListener {
JTextField userField;
JPasswordField passwordField;
JButton loginButton;
public LoginFrame() {
setTitle("Login");
setSize(300, 150);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints constraints = new GridBagConstraints();
constraints.fill = GridBagConstraints.HORIZONTAL;
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 1;
constraints.insets = new Insets(10, 10, 10, 10);
JLabel userLabel = new JLabel("Username: ");
panel.add(userLabel, constraints);
userField = new JTextField(20);
constraints.gridx = 1;
panel.add(userField, constraints);
JLabel passwordLabel = new JLabel("Password: ");
constraints.gridx = 0;
constraints.gridy = 1;
panel.add(passwordLabel, constraints);
passwordField = new JPasswordField(20);
constraints.gridx = 1;
panel.add(passwordField, constraints);
loginButton = new JButton("Login");
loginButton.addActionListener(this);
constraints.gridx = 0;
constraints.gridy = 2;
constraints.gridwidth = 2;
panel.add(loginButton, constraints);
add(panel);
setLocationRelativeTo(null);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
String user = userField.getText();
String password = new String(passwordField.getPassword());
if (user.equals("admin") && password.equals("password")) {
JOptionPane.showMessageDialog(this, "Welcome, " + user + "!");
dispose();
// Do something else, like opening the main application window
} else {
JOptionPane.showMessageDialog(this, "Invalid login", "Error", JOptionPane.ERROR_MESSAGE);
}
}
public static void main(String[] args) {
new LoginFrame();
}
}
```
这个示例使用了 Swing GUI 组件来实现登录界面。其中包括一个文本框用于输入用户名、一个密码框用于输入密码、以及一个登录按钮。当用户点击登录按钮时,程序会获取用户名和密码,并进行验证。如果验证通过,会弹出一个欢迎消息,并关闭登录窗口;否则会弹出一个错误消息。