1.编写程序，实现在窗口中显示“Hello JAVA!”，要求用两类Java程序编写并运行结果。 public class BaseText {
public static void main(String[] args) { System.out.println(\ } }
2. 编写程序，键盘输入两个数，计算并输出它们的积。 public class BaseText {
public static void main(String[] args) { if(args != null && args.length == 2) { try {
double num1 = Double.parseDouble(args[0]); double num2 = Double.parseDouble(args[1]);
System.out.println(\得到的乘积是:\ } catch (NumberFormatException e) { e.printStackTrace(); } }else {
System.out.println(\你输入的数据不正确,输入数据的格式样例为:12.3 4\ } } }
3. 编写程序，接受用户输入1～7之间的整数，若不符合条件则重新输入，利用swith语句输出星期几。 public class BaseText {
public static void main(String[] args) {
if(args != null && args.length == 1 ) { try {
double num = Double.parseDouble(args[0]);
int intValue = (int)num;
switch (intValue) { case 1:
System.out.println(\今天是星期一\ break; case 2:
System.out.println(\今天是星期二\ break;
case 3:
System.out.println(\今天是星期三\ break; case 4:
System.out.println(\今天是星期四\ break; case 5:
System.out.println(\今天是星期五\ break; case 6:
System.out.println(\今天是星期六\ break; case 7:
System.out.println(\今天是星期天\ break; default:
args = null;
System.out.println(\请重新输入\ break; }
} catch (NumberFormatException e) { e.printStackTrace(); } }else {
System.out.println(\你输入的数据不合法\ } } }
4. 编写程序，包括一个标签、一个文本框和一个按钮，当单击按钮时把文本框中的内容复制到标签中显示。
package test; import java.awt.Toolkit; import javax.swing.SwingUtilities; import javax.swing.UIManager; import java.awt.Dimension; public class Application { boolean packFrame = false; public Application() { Frame1 frame = new Frame1(); if (packFrame) { frame.pack(); } else { frame.validate(); } Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); Dimension frameSize = frame.getSize(); if (frameSize.height > screenSize.height) { frameSize.height = screenSize.height; } if (frameSize.width > screenSize.width) { frameSize.width = screenSize.width; } frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { try { UIManager.setLookAndFeel(UIManager. getSystemLookAndFeelClassName()); } catch (Exception exception) { exception.printStackTrace(); } new Application(); } }); } } package test; import java.awt.BorderLayout; import java.awt.Dimension; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JLabel; import java.awt.Color; import java.awt.Rectangle; import javax.swing.JButton; import javax.swing.JTextField; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class Frame1 extends JFrame { JPanel contentPane; JLabel jLabel1 = new JLabel(); JButton jButton1 = new JButton(); JTextField jTextField1 = new JTextField(); public Frame1() { try { setDefaultCloseOperation(EXIT_ON_CLOSE); jbInit(); } catch (Exception exception) { exception.printStackTrace(); } } private void jbInit() throws Exception { contentPane = (JPanel) getContentPane(); contentPane.setLayout(null); this.getContentPane().setBackground(new Color(139, 154, 255)); setSize(new Dimension(400, 300)); setTitle(\测试\ jLabel1.setText(\以前的数据\ jLabel1.setBounds(new Rectangle(88, 60, 195, 32)); jButton1.setBounds(new Rectangle(70, 175, 195, 33)); jButton1.setText(\点我看看\ jButton1.addActionListener(new Frame1_jButton1_actionAdapter(this)); jTextField1.setText(\ jTextField1.setBounds(new Rectangle(88, 109, 199, 31)); contentPane.add(jLabel1); contentPane.add(jButton1); contentPane.add(jTextField1); } public void jButton1_actionPerformed(ActionEvent e) { this.jLabel1.setText(this.jTextField1.getText()); this.jTextField1.setText(\ } } class Frame1_jButton1_actionAdapter implements ActionListener { private Frame1 adaptee; Frame1_jButton1_actionAdapter(Frame1 adaptee) { this.adaptee = adaptee; } public void actionPerformed(ActionEvent e) { adaptee.jButton1_actionPerformed(e);
