通过url下载文件HttpURLConnection

import java.io.*;
import java.net.*;
import java.util.*;

public class UrlDownload {

	public final static boolean DEBUG = true;//是否输出调试信息

	private static int BUFFER_SIZE = 8096;//缓冲区大小

	private Vector vDownLoad = new Vector();//URL列表

	private Vector vFileList = new Vector();//下载后的保存文件名列表

	/**
	 * 构造方法
	 */
	public UrlDownload() {

	}

	/**
	 * 清除下载列表
	 */
	public void resetList() {
		vDownLoad.clear();
		vFileList.clear();
	}

	/**
	 * 增加下载列表项
	 *
	 * @param url String
	 * @param filename String
	 */
	public void addItem(String url, String filename) {
		vDownLoad.add(url);
		vFileList.add(filename);
	}

	/**
	 * 根据列表下载资源
	 */
	public void downLoadByList() {
		String url = null;
		String filename = null;

		//按列表顺序保存资源
		for (int i = 0; i < vDownLoad.size(); i++) {
			url = (String) vDownLoad.get(i);
			filename = (String) vFileList.get(i);

			try {
				saveToFile(url, filename);
			} catch (IOException err) {
				if (DEBUG) {
					System.out.println("资源[" + url + "]下载失败!!!");
				}
			}
		}
		if (DEBUG) {
			System.out.println("下载完成!!!");

		}
	}

	/**
	 * 将HTTP资源另存为文件
	 *
	 * @param destUrl String
	 * @param fileName String
	 * @throws Exception
	 */
	public void saveToFile(String destUrl, String fileName) throws IOException {
		FileOutputStream fos = null;
		BufferedInputStream bis = null;
		HttpURLConnection httpUrl = null;
		URL url = null;
		byte[] buf = new byte[BUFFER_SIZE];
		int size = 0;

		//建立链接
		url = new URL(destUrl);
		httpUrl = (HttpURLConnection) url.openConnection();
		//连接指定的资源
		httpUrl.connect();
		//获取网络输入流
		bis = new BufferedInputStream(httpUrl.getInputStream());
		//建立文件
		File file = new File(fileName);
		if(!file.exists()) {
			if(!file.getParentFile().exists()) {
				file.getParentFile().mkdirs();
			}
			file.createNewFile();
		}
		fos = new FileOutputStream(fileName);

		if (this.DEBUG)
			System.out.println("正在获取链接[" + destUrl + "]的内容...\n将其保存为文件["
					+ fileName + "]");

		//保存文件
		while ((size = bis.read(buf)) != -1)
			fos.write(buf, 0, size);

		fos.close();
		bis.close();
		httpUrl.disconnect();
	}

	/**
	 * 设置代理服务器
	 * @param proxy String
	 * @param proxyPort String
	 */
	public void setProxyServer(String proxy, String proxyPort) {
		System.getProperties().put("proxySet", "true");
		System.getProperties().put("proxyHost", proxy);
		System.getProperties().put("proxyPort", proxyPort);

	}

	/**
	 * 设置认证用户名与密码
	 * @param uid String
	 * @param pwd String
	 */
	public void setAuthenticator(String uid, String pwd) {
		//Authenticator.setDefault(new MyAuthenticator(uid, pwd));
	}

	/**
	 * 主方法(用于测试)
	 * @param argv String[]
	 * @throws IOException 
	 */
	public static void main(String argv[]) throws IOException {
		UrlDownload oInstance = new UrlDownload();
		oInstance.addItem("http://192.168.1.2/demos/1.zip", "c:/1.zip");
		oInstance.downLoadByList();
	}
}