基本原理：
JDK6u10版本以上提供了DeskTop的API接口支持，可以根据URI参数自动打开
操作系统默认的浏览器来加载对应的网页，同时借助JDK的Robot类实现自动截屏
这样就完成了对任意一个URL对应网页保存为图片。程序如下：
package com.gloomyfish.image.util;import java.awt.AWTException;import java.awt.Rectangle;import java.awt.Robot;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.net.URI;import javax.imageio.ImageIO;public class DeskTopTest {public static void main(String[] args) {if (!java.awt.Desktop.isDesktopSupported()) {System.err.println("Desktop is not supported (fatal)");System.exit(1);}java.awt.Desktop desktop = java.awt.Desktop.getDesktop();if (!desktop.isSupported(java.awt.Desktop.Action.BROWSE)) {System.err.println("Desktop doesn't support the browse action (fatal)");System.exit(1);}try {URI uri = URI.create("http://www.csdn.net");desktop.browse(uri);Thread.sleep(8000); // 8 seconds is enough to load the any page.Robot robot = new Robot();// Rectangle rectangle = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize() );Rectangle rectangle = new Rectangle(300, 90, 1000, 720);BufferedImage image = robot.createScreenCapture(rectangle);File outputfile = new File("D:\\agriculture\\test.jpg");ImageIO.write(image, "jpg", outputfile);} catch (IOException e) {e.printStackTrace();} catch (AWTException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();} }}
缺点：
程序运行时用户不能有其它操作，否则可能保存错误截屏。 这里
假设加载一个网页时间最长为8秒.
用最少的浪费面对现在
