Java FTP上传延迟

我对ftp上传有一个奇怪的问题。我正在尝试将zip文件上载到ftp服务器。它工作正常，除非互联网连接非常慢（我们测试的是56kbps）。当我在100%传输后通过FTP上传文件时，需要一些时间才能完成（取决于文件大小，大约需要2分钟到20分钟）

如果您看到最后两个日志项，则需要2分钟来触发回调，尽管上传完成了100%。我不知道为什么会触发回调。你能解释一下吗

07-02 10:34:38.112:D/FTP（1646）：传输26661次2014-07-02 10:34:38
07-02 10:42:15.462:D/FTP（1646）：完成2014-07-02 10:36:27

提前谢谢

看看我的代码

package com.androidexample.ftpdemo;

import it.sauronsoftware.ftp4j.FTPClient;
import it.sauronsoftware.ftp4j.FTPDataTransferListener;

import java.io.File;
import java.util.Date;

import android.app.Activity;
import android.os.Build;
import android.os.Bundle;
import android.os.StrictMode;
import android.os.StrictMode.ThreadPolicy;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

import com.kpbird.ftpdemo.R;

public class FtpUpload extends Activity implements OnClickListener {

    /********* work only for Dedicated IP ***********/
    static final String FTP_HOST = "";

    /********* FTP USERNAME ***********/
    static final String FTP_USER = "";

    /********* FTP PASSWORD ***********/
    static final String FTP_PASS = "";

    Button btn;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btn = (Button) findViewById(R.id.button1);
        btn.setOnClickListener(this);

    }

    public void onClick(View v) {

        // Upload sdcard file
        File f = new File("/sdcard/test.zip");

        uploadFile(f);

    }

    public void uploadFile(File fileName) {

        if (Build.VERSION.SDK_INT >= 10) {
            ThreadPolicy tp = ThreadPolicy.LAX;
            StrictMode.setThreadPolicy(tp);
        }
        FTPClient client = new FTPClient();

        try {

            client.connect(FTP_HOST);
            client.login(FTP_USER, FTP_PASS);
            client.setType(FTPClient.TYPE_BINARY);

            client.upload(fileName, new MyTransferListener());

        } catch (Exception e) {
            btn.setVisibility(View.VISIBLE);
            e.printStackTrace();
            try {
                client.disconnect(true);
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }

    }

    /******* Used to file upload and show progress **********/

    public class MyTransferListener implements FTPDataTransferListener {

        public void started() {

            // Transfer started
            Log.d("FTP", " started");

        }

        public void transferred(int length) {
            Date d = new Date();
            CharSequence s = DateFormat.format("yyyy-MM-dd hh:mm:ss",
                    d.getTime());

            Log.d("FTP", " transferred" + length + "time" + s);
        }

        public void completed() {

            // Transfer completed
            Date d = new Date();
            CharSequence s = DateFormat.format("yyyy-MM-dd hh:mm:ss",
                    d.getTime());
            Log.d("FTP", " completed " + s);

        }

        public void aborted() {
            // Transfer aborted
            Date d = new Date();
            CharSequence s = DateFormat.format("yyyy-MM-dd hh:mm:ss",
                    d.getTime());
            Log.d("FTP", " aborted " + s);

        }

        public void failed() {
            // Transfer failed
            Date d = new Date();
            CharSequence s = DateFormat.format("yyyy-MM-dd hh:mm:ss",
                    d.getTime());
            Log.d("FTP", " failed " + s);

        }

    }

}

请参阅下面给出的日志，完成后延迟2分钟

07-02 10:27:48.602: D/FTP(1646):  started   
07-02 10:27:48.637: D/FTP(1646):  transferred65536time2014-07-02 10:27:48             
07-02 10:27:48.672: D/FTP(1646):  transferred65536time2014-07-02 10:27:48          
07-02 10:27:48.712: D/FTP(1646):  transferred65536time2014-07-02 10:27:48           
07-02 10:27:48.747: D/FTP(1646):  transferred65536time2014-07-02 10:27:48           
07-02 10:27:48.797: D/FTP(1646):  transferred65536time2014-07-02 10:27:48         
07-02 10:27:48.822: D/FTP(1646):  transferred65536time2014-07-02 10:27:48         
07-02 10:27:48.842: D/FTP(1646):  transferred65536time2014-07-02 10:27:48        
07-02 10:27:48.867: D/FTP(1646):  transferred65536time2014-07-02 10:27:48           
07-02 10:27:48.892: D/FTP(1646):  transferred65536time2014-07-02 10:27:48        
07-02 10:27:48.927: D/FTP(1646):  transferred65536time2014-07-02 10:27:48           
07-02 10:27:48.992: D/dalvikvm(1646): GC_FOR_ALLOC freed 216K, 10% free 12224K/13500K, paused 28ms, total 33ms            
07-02 10:27:48.997: D/FTP(1646):  transferred65536time2014-07-02 10:27:48           
07-02 10:27:49.072: D/FTP(1646):  transferred65536time2014-07-02 10:27:49      
07-02 10:28:29.047: D/FTP(1646):  transferred65536time2014-07-02 10:28:29     
07-02 10:28:29.112: D/FTP(1646):  transferred65536time2014-07-02 10:28:29  
07-02 10:28:29.137: D/FTP(1646):  transferred65536time2014-07-02 10:28:29   
07-02 10:28:29.162: D/FTP(1646):  transferred65536time2014-07-02 10:28:29      
07-02 10:29:09.992: D/FTP(1646):  transferred65536time2014-07-02 10:29:09     
07-02 10:29:10.057: D/FTP(1646):  transferred65536time2014-07-02 10:29:10    
07-02 10:29:10.112: D/FTP(1646):  transferred65536time2014-07-02 10:29:10     
07-02 10:29:10.172: D/FTP(1646):  transferred65536time2014-07-02 10:29:10      
07-02 10:30:35.052: D/FTP(1646):  transferred65536time2014-07-02 10:30:35     
07-02 10:30:35.147: D/FTP(1646):  transferred65536time2014-07-02 10:30:35        
07-02 10:30:35.207: D/FTP(1646):  transferred65536time2014-07-02 10:30:35        
07-02 10:30:35.252: D/FTP(1646):  transferred65536time2014-07-02 10:30:35          
07-02 10:31:05.617: D/FTP(1646):  transferred65536time2014-07-02 10:31:05          
07-02 10:31:05.682: D/FTP(1646):  transferred65536time2014-07-02 10:31:05          
07-02 10:31:05.742: D/FTP(1646):  transferred65536time2014-07-02 10:31:05          
07-02 10:31:05.792: D/FTP(1646):  transferred65536time2014-07-02 10:31:05         
07-02 10:31:05.822: D/FTP(1646):  transferred65536time2014-07-02 10:31:05        
07-02 10:31:05.857: D/FTP(1646):  transferred65536time2014-07-02 10:31:05        
07-02 10:31:05.887: D/FTP(1646):  transferred65536time2014-07-02 10:31:05         
07-02 10:31:47.082: D/FTP(1646):  transferred65536time2014-07-02 10:31:47       
07-02 10:31:47.157: D/FTP(1646):  transferred65536time2014-07-02 10:31:47       
07-02 10:31:47.217: D/FTP(1646):  transferred65536time2014-07-02 10:31:47          
07-02 10:31:47.267: D/FTP(1646):  transferred65536time2014-07-02 10:31:47     
07-02 10:32:27.737: D/FTP(1646):  transferred65536time2014-07-02 10:32:27         
07-02 10:32:27.802: D/FTP(1646):  transferred65536time2014-07-02 10:32:27        
07-02 10:32:27.862: D/FTP(1646):  transferred65536time2014-07-02 10:32:27          
07-02 10:32:27.917: D/FTP(1646):  transferred65536time2014-07-02 10:32:27           
07-02 10:32:27.967: D/FTP(1646):  transferred65536time2014-07-02 10:32:27           
07-02 10:33:39.422: D/FTP(1646):  transferred65536time2014-07-02 10:33:39        
07-02 10:33:39.482: D/FTP(1646):  transferred65536time2014-07-02 10:33:39           
07-02 10:33:39.542: D/FTP(1646):  transferred65536time2014-07-02 10:33:39         
07-02 10:33:39.587: D/FTP(1646):  transferred65536time2014-07-02 10:33:39   
07-02 10:33:49.692: D/FTP(1646):  transferred65536time2014-07-02 10:33:49     
07-02 10:33:49.792: D/FTP(1646):  transferred65536time2014-07-02 10:33:49       
07-02 10:33:49.842: D/FTP(1646):  transferred65536time2014-07-02 10:33:49          
07-02 10:33:49.887: D/FTP(1646):  transferred65536time2014-07-02 10:33:49         
07-02 10:34:37.902: D/FTP(1646):  transferred65536time2014-07-02 10:34:37       
07-02 10:34:37.967: D/FTP(1646):  transferred65536time2014-07-02 10:34:37         
07-02 10:34:38.017: D/FTP(1646):  transferred65536time2014-07-02 10:34:38         
07-02 10:34:38.067: D/FTP(1646):  transferred65536time2014-07-02 10:34:38           
07-02 10:34:38.112: D/FTP(1646):  transferred26661time2014-07-02 10:34:38     
07-02 10:42:15.462: D/FTP(1646):  completed 2014-07-02 10:36:27   

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你想在上面显示进度条吗？我们已经在使用进度条了，我们只想知道ftp完成延迟的原因和解决方法。