使用Java代码将目录的多媒体文件下载到我的本地计算机中

Question

I have a java code which i would be using to download the files from a directory in a remote machine.Now is use the ftp class available to do the same.The problem arises when i run the code which results in all the files being downloaded but when i see the size of all of them i see that all are of zero bytes and do not contain anything either.Kindly help if you can to analyze what could be the possible reason behind this?

package login.multiple;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.SocketException;

import org.apache.commons.*; 
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPFile;

public class Downloader {

    /**
     * @param args
     * @throws FTPException 
     * @throws FTPIllegalReplyException 
     * @throws IOException 
     * @throws IllegalStateException 
     * @throws FTPListParseException 
     * @throws FTPAbortedException 
     * @throws FTPDataTransferException 
     */
    public static void main(String[] args)  {
        // TODO Auto-generated method stub
        FTPFile[] list = null;
        String fileNames[];
        String path = "\\Users\\XXX\\Documents\\Downloads\\Coldplay - Mylo Xyloto [mp3-vbr-2011]";
        int i = 0;
        FileOutputStream fos = null;
        FTPClient client = new FTPClient();
        //client.connect("192.168.1.2");
        try {
            client.connect("127.0.0.1");
            client.login("xxx", "yyy");
            list = client.listFiles(path);
            for(i=0;i<list.length;i++){
            //for(i=0;i<1;i++){
                fos = new FileOutputStream(list[i].getName());
                client.retrieveFile(path + list[i].getName(), fos);
            }
        } catch (SocketException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        try {
            client.disconnect();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        }
    }

Answer 1

Since you are opening the FileOutputStream , a good chance is that you are responsible for closing it, too. Add fos.close() after client.retrieveFile . Your try-catch design is a mess, too. It will help the diagnostics if you get it right. Put everything after client.connect into a try {...} finally { client.disconnect(); } try {...} finally { client.disconnect(); } and declare your main method as throws Exception . That will give you a fail-fast behaviour.