import java.io.*; public class FISDemo {
public static void main(String args[]) { byte[] buf=new byte[2056]; try{
FileInputStream fileIn=new FileInputStream(\ int bytes=fileIn.read(buf,0,2056); String str=new String(buf,0,bytes); System.out.println(str); }catch(Exception e){ e.printStackTrace( );
}
}
7、编写一个Java程序将当100,101,102,103,104,105个数以数组的形式写入到Dest.txt文件中，并以相反的顺序读出显示在屏幕上。（p190,例7-2）
//programme name IODemo.java import java.io.*;
public class IODemo {
public static void main( String args[] ) { int data[] = {100,101,102,103,104,105};
int t; try
{ DataOutputStream out = new DataOutputStream (new FileOutputStream(“dest.txt”)); for(int i=0;i DataInputStream in = new DataInputStream (new FileInputStream(“dest.txt”)); for(int i= data.length-1;i>= 0;i--) { t=in.readInt(data[i]); System.out.print(“ ”+t); } System.out.println( ); in.close(); }catch(IOException e) { System.out.println(e.getMessage());} } } 8. 利用Applet类和Runnable接口实现滚动字幕，其中字幕文字（“学好Java有工作”）和 时间间隔（“200”）需要由页面文件中 import java.awt.Color; import java.awt.Graphics; import javax.swing.JApplet; public class MoveMessage extends JApplet implements Runnable { String str; int time; private Thread thread; public void init() { } public void start() { } public void run() { int x = 0; Graphics g = getGraphics(); while (true) { } try { Thread.sleep(time); thread.start(); setBackground(Color.PINK); str = getParameter(\String timeArg = getParameter(\time = Integer.parseInt(timeArg);; thread = new Thread(this); } catch (Exception e) { } g.clearRect(0, 0, getWidth(), getHeight()); g.drawString(str, x, 30); x += 2; if (x >= getWidth()) x = 0; e.printStackTrace(); } }
9、编写一个Java程序实现多线程，在线程中输出线程的名字，隔300毫秒输出一次，共输出20次。（p202,例8-1）
// programme name TestThread; // 声明一个子线程类Threaddemo; class ThreadDemo extends Thread { public ThreadDemo(String str) { super(str); }
public void run() { for(int i=0;i<20;i++){
System.out.print(“ ”+this.getName()); Try { Sleep(300);
}catch(InterruptedException e){ System.out.println(e.getMessage()); Return; } }
System.out.println(“ /end”); } }
public class TestThread {
public static void main( String args[] ) {
ThreadDemo thread1=new ThreadDemo(“T1”); ThreadDemo thread2=new ThreadDemo(“T2”); ThreadDemo thread3=new ThreadDemo(“T3”); thread1.start(); thread2.start(); thread3.start(); } }
10. 编写程序，在屏幕上显示带标题的窗口，并添加一个按钮。当用户单击按钮时，结束程序。
// Programme Name ButtonEventDemo.java import javax.swing.*; import java.awt.event.*;
public class ButtonEventDemo extends JPanel implements ActionListener{
protected JButton b1; public ButtonEventDemo() {
//声明一个按钮对象 //构造方法
ImageIcon ButtonIcon = new ImageIcon(\ //创建按钮的图标对
象
b1 = new JButton(\退出按钮\ //生成按钮对象
b1.setMnemonic(KeyEvent.VK_E); //设置b1的助记符是Alt+E
b1.setToolTipText(\这是退出按钮。\ this.add(b1); //往面板对象中加载按钮
b1.addActionListener(this); //本类对象注册为按钮的事件监听器 }
public void actionPerformed(ActionEvent e){
//按钮事件响应方法 // 设置按钮提示条
System.exit(0); //按b1则退出主程序 }
private static void createGUI() { //创建窗体
JFrame.setDefaultLookAndFeelDecorated(true); //设置java隐含观感 JFrame frame = new JFrame(\按钮测试\生成应用程序主窗体
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //设置关闭时隐含操作