《java小程序--10-10--北大计算机系java培训讲义.ppt

* 2.4 URL类 构造URL的实例 import .URL; import .MalformedURLException; public class Test { URL url1,url2,url3; void test() { try { url1= new URL(“file:/D:/image/example.gif”); url2= new URL(“/cv/”); url1= new URL(url2, “hit.gif”); }catch (MalformedURLException e); //处理例外 } }｝ Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.5 载入现有图像文件 Image类 java支持gif和jpg两种格式的图像 图像文件的URL: URL picurl= new URL (“/Applet/img1.gif”); 取一幅图像构成图像对象 Image img1 = getImage(picurl); Image img2 = getImage(getCodeBase(), “img2.gif”); Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.5 载入现有图像文件 显示一幅图像: g.drawImage(img1, x, y, this); g.drawImage(img1, x, y,Color.red, this); g.drawImage(image1, x, y,x2,y2,Color.red, this); 规定背景 规定尺寸 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.5 载入现有图像文件 完整的过程 不要忘记AWT包 定义Image对象了吗? 指定图像的URL了吗? 把图像取出来吧. 还记得画图像用什么方法和命令吗? 在类中 在init0中 在paint0中 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.5 载入现有图像文件 import java.applet.*;import java.awt.*; public class image extends Applet { Image img; public void init() { img=getImage(getCodeBase(),img0001.gif);} public void paint(Graphics g) { int width=img.getWidth(this); int height=img.getHeight(this); g.drawRect(52,52,width+30,height+30); g.drawImage(img,57,57,width+20,height+20,this);}} Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.6 动态效果线程的应用 2.4 动态效果线程的应用 什么是线程? 线程是执行中的程序中的单个顺序控制流. Java支持多线程 开始 显示进度 引出最后结果 数学运算 线程1 线程2 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile . Copyright 2004-2011 Aspose Pty Ltd. * 2.6 动态效果线程的