Java實現一個登錄窗體功能

This program shows a "Login" window based on Swing JFrame. When you input the correct userID and Password, you can obtain a confirmation, or else you will be alerted by a JAVA standard message window.

The Swing JFrame used in the same time the GridLayout for the Container and the FlowLayout for the JPanel.

1. package com.han;
3. import java.awt.Container;
4. import java.awt.FlowLayout;
5. import java.awt.GridLayout;
6. import java.awt.event.ActionEvent;
7. import java.awt.event.ActionListener;
8. import java.util.Arrays;
10. import javax.swing.*;
12. /**
13. * This program shows a "Login" window based on Swing JFrame.
14. * When you input the correct userID and Password, you can obtain a confirmation,
15. * or else you will be alerted by a JAVA standard message window.
16. * <p>
17. * The Swing JFrame used in the same time the GridLayout for the Container and the FlowLayout for the JPanel.
18. * @author han
19. *
20. */
21. public class SwingJFrameLogin {
22. /*define all the necessary member variables*/
23. String s1=null;
24. char[] s2=null;
25. JFrame frame=new JFrame();
26. Container c=frame.getContentPane();
27. /*the construct function*/
28. public SwingJFrameLogin() {
29. c.setLayout(new GridLayout(3,1,10,10));//the Container uses the GridLayout for 3 JPanels
30. JPanel panel1=new JPanel(new FlowLayout(FlowLayout.CENTER));//each JPanel uses the FlowLayout
31. JPanel panel2=new JPanel(new FlowLayout(FlowLayout.CENTER));
32. JPanel panel3=new JPanel(new FlowLayout());
33. JLabel label1=new JLabel("用戶名：");
34. final JTextField jt=new JTextField(10);
35. JLabel label2=new JLabel("密碼：");
36. final JPasswordField jp=new JPasswordField(6);
37. jp.setEchoChar((char) 0);//set the display words as visible.
38. final JButton jb1 = new JButton("提交");
39. final JButton jb2 = new JButton("重置");
40. panel1.add(label1);
41. panel1.add(jt);
42. panel2.add(label2);
43. panel2.add(jp);
44. panel3.add(jb1);
45. panel3.add(jb2);
46. c.add(panel1);
47. c.add(panel2);
48. c.add(panel3);
49. jb1.addActionListener(new ActionListener(){
50. @Override
51. public void actionPerformed(ActionEvent e) {
52. String s1=jt.getText();
53. char[] s2=jp.getPassword();
54. System.out.println(s1);
55. System.out.println(s2);
56. char[] pw={'u','p','s'};
57. /*System.out.println(Arrays.equals(s2,pw));
58. System.out.println(s1.equals("han"));*/
59. if (s1.equals("han") && Arrays.equals(s2,pw)) {
60. JOptionPane.showMessageDialog(frame,
61. "登錄成功 ！","Message",JOptionPane.INFORMATION_MESSAGE);
62. //frame.dispose();（等同於點擊關閉窗口時執行frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE );）
63. System.exit(0);//正常退出（等同於點擊關閉窗口時執行frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );）
64. }
65. else {
66. JOptionPane.showMessageDialog(frame,//it is a JAVA internal STD message BOX
67. "You had input a wrong userID !!","Warning",JOptionPane.WARNING_MESSAGE);
68. }
69. Arrays.fill(s2,'0'); //Zero out the possible password, for security.
70. }
71. });
72. jb2.addActionListener(new ActionListener(){
73. @Override
74. public void actionPerformed(ActionEvent e) {//set all the fields empty.
75. jt.setText("");
76. jp.setText("");
77. }
78. });
79. frame.pack();//automatically resize all the components to their preferred sizes.
80. frame.setVisible(true);
81. frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
82. }
84. public static void main(String[] args) {
85. new SwingJFrameLogin();
86. }
87. }