Java自动下载指定URl的文件

package t;

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

public class HttpGet {
  public final static boolean DEBUG = true; //调试用
  private static int BUFFER_SIZE = 8096; //缓冲区大小

  /**
   * 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
    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();
  }

  public static void main(String argv[]) {
    HttpGet oInstance = new HttpGet();
    String url = "http://www.zhcw.com/data-js/data50.js";
    String fileName = "E:\\tt.js";
    try {
      oInstance.saveToFile(url, fileName);
    }
    catch (Exception err) {
      System.out.println(err.getMessage());
    }
  }
}