revolve.java

里面包含了多个java的编程示例！而且举出初学者常常遇到的错误！

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.*;

public class Revolve extends JApplet
    implements Runnable, ActionListener {

    String[] pageTitle = new String[6];
    URL[] pageLink = new URL[6];
    Color butterscotch = new Color(255, 204, 158);
    int current = 0;
    Thread runner;

    public void init() {
        pageTitle[0] = "Sun's Java site";
        pageLink[0] = getURL("http://java.sun.com");
        pageTitle[1] = "Cafe au Lait";
        pageLink[1] = getURL("http://www.ibiblio.org/javafaq");
        pageTitle[2] = "JavaWorld";
        pageLink[2] = getURL("http://www.javaworld.com");
        pageTitle[3] = "Java 2 in 24 Hours";
        pageLink[3] = getURL("http://www.java24hours.com");
        pageTitle[4] = "Sams Publishing";
        pageLink[4] = getURL("http://www.samspublishing.com");
        pageTitle[5] = "Workbench";
        pageLink[5] = getURL("http://www.cadenhead.org/workbench");
        Button goButton = new Button("Go");
        goButton.addActionListener(this);
        FlowLayout flow = new FlowLayout();
        setLayout(flow);
        add(goButton);
    }

    URL getURL(String urlText) {
        URL pageURL = null;
        try {
            pageURL = new URL(getDocumentBase(), urlText);
        } catch (MalformedURLException m) { }
        return pageURL;
    }

    public void paint(Graphics screen) {
        Graphics2D screen2D = (Graphics2D) screen;
        screen2D.setColor(butterscotch);
        screen2D.fillRect(0, 0, getSize().width, getSize().height);
        screen2D.setColor(Color.black);
        screen2D.drawString(pageTitle[current], 5, 60);
        screen2D.drawString("" + pageLink[current], 5, 80);
    }

    public void start() {
        if (runner == null) {
            runner = new Thread(this);
            runner.start();
        }
    }

    public void run() {
        Thread thisThread = Thread.currentThread();
        while (runner == thisThread) {
            current++;
            if (current > 5) {
                current = 0;
            }
            repaint();
            try {
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                // do nothing
            }
        }
    }

    public void stop() {
        if (runner != null) {
            runner = null;
        }
    }

    public void actionPerformed(ActionEvent evt) {
        if (runner != null) {
            runner = null;
        }
        AppletContext browser = getAppletContext();
        if (pageLink[current] != null) {
            browser.showDocument(pageLink[current]);
        }
    }
}