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


public class HttpGet {

  public final static boolean DEBUG = true;//調試用
  private static int BUFFER_SIZE = 8096;//緩沖區大小
  private Vector<String> vDownLoad = new Vector<String>();//URL列表
  private Vector<String> vFileList = new Vector<String>();//下載后的保存文件名列表

  /**
   * 構造方法
   */
  public HttpGet() {

  }

  /**
   * 增加下載列表項
   */
  public void addItem(String url, String filename) {
    vDownLoad.add(url);
    vFileList.add(filename);
  }

  /**
   * 根據列表下載資源
   */
  public void downLoadByList() {
    String url = null;
    String filename = null;
    
    //按列表順序保存資源
    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("資源[" + url + "]下載失敗!!!");
        }
        err.printStackTrace();
      }
    }

    if (DEBUG) {
      System.out.println("下載完成!!!");

    }
  }

  // 將HTTP資源另存為文件
 
 
  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;
    
    //建立鏈接
    url = new URL(destUrl);
    httpUrl = (HttpURLConnection) url.openConnection();
    //連接指定的資源
    httpUrl.connect();
    //獲取網絡輸入流
    bis = new BufferedInputStream(httpUrl.getInputStream());
    //建立文件
    fos = new FileOutputStream(fileName);

    if (this.DEBUG) 
	  System.out.println("正在獲取鏈接[" + destUrl + "]的內容...\n將其保存為文件[" + fileName + "]");

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




  // 主方法(用于測試)

  
  public static void main(String argv[]) {

    HttpGet oInstance = new HttpGet();
	try {
		//增加下載列表（此處用戶可以寫入自己代碼來增加下載列表）
      	oInstance.addItem("http://www.google.cn/music/chartlisting?q=chinese_new_songs_cn&cat=song&grouping=new-release_music/大丈夫.mp3","./大丈夫.mp3");
		oInstance.addItem("http://www.91ylhx.cn/music/media/wmnrsz.wma","./wmnrsz.wma");
		oInstance.addItem("http://www.ebook.com/java/網絡編程003.zip","./網絡編程3.zip");
		oInstance.addItem("http://www.ebook.com/java/網絡編程004.zip","./網絡編程4.zip");
		oInstance.addItem("http://www.ebook.com/java/網絡編程005.zip","./網絡編程5.zip");
		oInstance.addItem("http://www.ebook.com/java/網絡編程006.zip","./網絡編程6.zip");
		oInstance.addItem("http://www.ebook.com/java/網絡編程007.zip","./網絡編程7.zip");
		//開始下載
		oInstance.downLoadByList();
    }
    catch (Exception err) {
      System.out.println(err.getMessage());
    }

  }

}