imageexample.java

window下使用j2ee的jms工具做的网络应用的一个架构程序

/*
This applet will display a gif on screen
for now the gif file must be in the same directory as this applet
*/

import java.awt.*;
import java.applet.*;
// These classes are for Url's.
import java.net.*;

public class ImageExample extends Applet
{
	// Your image name;
	Image my_gif;
	
	// The applet base URL
	URL base;
	
	// This object will allow you to control loading
	MediaTracker mt;
	
	public void init() 
	{
		
		// initialize the MediaTracker
		mt = new MediaTracker(this);
		
		// The try-catch is necassary when the URL isn't valid
		// Ofcourse this one is valid, since it is generated by
		// Java itself.
		
		try {
			// getDocumentbase gets the applet path.
			base = getDocumentBase();
		}
		catch (Exception e) {}
		
		// Here we load the image.
		// Only Gif and JPG are allowed. Transparant gif also.
		my_gif = getImage(base,"imageExample.gif");
		
		// tell the MediaTracker to kep an eye on this image, and give it ID 1;
		mt.addImage(my_gif,1);

		// now tell the mediaTracker to stop the applet execution
		// (in this example don't paint) until the images are fully loaded.
		// must be in a try catch block.
		
		try {
			mt.waitForAll();
		}
		catch (InterruptedException  e) {}
		
		// when the applet gets here then the images is loaded.
		
	}
	
	public void paint(Graphics g) 
	{
		// now we are going to draw the gif on the screen
		// (image name,x,y,observer);
		
		g.drawImage(my_gif,20,20,this);

		// you can resize the image easily
		
		g.drawImage(my_gif,20,140,30,40,this);


	}
	
}

// That's all. Images can alos be drawn without the mediaTracker but then
// the screen will flicker.
// a base URL variable is also not necessary but when you have lots of images to load
// then it's shorter to type.

// Next is the basic GUI (Grphical User Interface) components.
// go to guiExample.java