单线程下载网络资源（摘自书：《你必须知道的261个Java问题》）

package com.zeph.java261.singlethreaddl;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.net.MalformedURLException;import java.net.URL;import java.net.URLConnection;public class Stdownload {public static void main(String[] args) {URL url;try {url = new URL("http://www.stonept.org/attachments/201205/201205251005497fe0b82f54d2ad7fd3e8fafb84bd49d9.jpg");URLConnection conn = url.openConnection();conn.connect();InputStream is = conn.getInputStream();String fileStr = url.getFile();String fileName = fileStr.substring(fileStr.lastIndexOf('/') + 1);FileOutputStream fos = new FileOutputStream("D://" + fileName);byte[] buffer = new byte[1024];int size = -1;while ((size = is.read(buffer)) != -1) {fos.write(buffer, 0, size);}fos.close();is.close();} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}