1.获取两个文本域的输入并求和，然后显示在第三个文本域中。

程序如下：

1 package WindowBuilder;

2 import java.awt.;

3 import java.awt.event.;

4 import javax.swing.*;

5 import javax.swing.border.EmptyBorder;

6

7 public class MyJFrame extends JFrame

8 {

9 private JPanel contentPane;

10 private final JTextPane textPane_1 = new JTextPane();

11 public static void main(String[] args)

12 {

13 try

14 {

15 MyJFrame frame = new MyJFrame();

16 frame.setVisible(true);

17 }

18 catch (Exception e)

19 {

20 e.printStackTrace();

21 }

22

23 }

24 public MyJFrame() {

25 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

26 setBounds(100, 100, 450, 300);

27 contentPane = new JPanel();

28 contentPane.setBackground(Color.LIGHT_GRAY);

29 contentPane.setBorder(BorderFactory.createEmptyBorder());//窗口设置为无边框

30 setContentPane(contentPane); //把contentPane对象设置成为MyFrame的内容面板

31 contentPane.setLayout(null);

32

33 JButton btnNewButton = new JButton("\u786E\u5B9A");

34 btnNewButton.setFont(new Font("楷体", Font.PLAIN, 12));

35 btnNewButton.setBackground(Color.RED);

36 btnNewButton.addActionListener(new ActionListener()

37 {

38 public void actionPerformed(ActionEvent e)

39 {

40 System.exit(EXIT_ON_CLOSE);

41 }

42 });

43 btnNewButton.setBounds(343, 234, 89, 24);

44 contentPane.add(btnNewButton);

45 btnNewButton.setVerticalAlignment(SwingConstants.BOTTOM);//垂直窗口底端

46

47 JButton btnNewButton_1 = new JButton("\u53D6\u6D88");

48 btnNewButton_1.setFont(new Font("楷体", Font.PLAIN, 12));

49 btnNewButton_1.setBackground(Color.CYAN);

50 btnNewButton_1.setBounds(8, 233, 89, 24);

51 contentPane.add(btnNewButton_1);

52

53 JLabel label = new JLabel("\u6587\u672C\u57DF1\uFF1A");

54 label.setFont(new Font("楷体", Font.PLAIN, 12));

55 label.setBounds(14, 51, 58, 15);

56 contentPane.add(label);

57

58 JTextArea textArea = new JTextArea();

59 textArea.setLineWrap(true);

60 textArea.setWrapStyleWord(true);

61 textArea.setBounds(72, 47, 110, 80);

62 contentPane.add(textArea);

63

64 JLabel label_1 = new JLabel("\u6587\u672C\u57DF2\uFF1A");

65 label_1.setFont(new Font("楷体", Font.PLAIN, 12));

66 label_1.setBounds(207, 51, 58, 15);

67 contentPane.add(label_1);

68

69 JLabel label_2 = new JLabel("\u6587\u672C\u57DF3\uFF1A");

70 label_2.setFont(new Font("楷体", Font.PLAIN, 12));

71 label_2.setBounds(109, 170, 58, 15);

72 contentPane.add(label_2);

73

74 JTextArea textArea_2 = new JTextArea();

75 textArea_2.setLineWrap(true);//设置自动换行

76 textArea_2.setBounds(265, 49, 110, 80);

77 contentPane.add(textArea_2);

78

79 JPanel panel = new JPanel();

80 panel.setBounds(162, 156, 158, 80);

81 contentPane.add(panel);

82 panel.setLayout(null);

83

84 JScrollPane scrollPane = new JScrollPane(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);//滑动条设置为需要时出现

85 scrollPane.setBounds(0, 0, 158, 80);

86 panel.add(scrollPane);

87

88 JTextArea textArea_1 = new JTextArea(0,0);

89 textArea_1.setEditable(false);

90 textArea_1.setWrapStyleWord(true);

91 scrollPane.setViewportView(textArea_1); //scrollPane显示可滚动的子元素

92

93 JButton btnSum = new JButton("Sum");

94 btnSum.addActionListener(new ActionListener() {

95 public void actionPerformed(ActionEvent e)

96 {

97 textArea_1.setEditable(true);

98 String s=textArea.getText()+textArea_2.getText();

99 textArea_1.setText(s);

100 textArea.setText("");

101 textArea_2.setText("");

102 textArea_1.setEditable(false);

103 btnSum.setEnabled(false);

104 }

105 });

106 btnSum.setBounds(335, 156, 97, 23);

107 contentPane.add(btnSum);

108 }

109 }