用sun的FTPClient 进行文件下载get的时候 ftpClient.get(remoteFileNameA);
抛异常

sun.net.ftp.FtpProtocolException: PORT :501 EPRT not allowed after EPSV ALL

    at sun.net.ftp.FtpClient.openDataConnection(FtpClient.java:435)
    at sun.net.ftp.FtpClient.get(FtpClient.java:550)
    at util.FtpClientUtil.updown(FtpClientUtil.java:247)
    at handler.ProviderHandler.providerMessageProc(ProviderHandler.java:100)
    at com.ibm.adapter.handler.AdapterHandler.process(Unknown Source)
    at com.ibm.handler.BaseHandler.executeRun(Unknown Source)
    at com.ibm.handler.BaseHandler.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:619)

程序：

...
private static FtpClient ftpClient;
...
public static String updown(String remoteFileNameA, String remoteFileNameB,
            FileInfo fileInfo) throws Exception {
        TelnetInputStream is = null;
        TelnetOutputStream os = null;
        FileOutputStream fos = null;
        MD5 md = new MD5();
        File inFile = new File(remoteFileNameA);
        FileService filService = new FileService();
        try {

        //  ftpClient.sendServer("quote PASV\r\n");
        //  ftpClient.sendServer("quote PORT\r\n");
                ftpClient.sendServer("type c 935\r\n");
            ftpClient.readServerResponse();
            **is = ftpClient.get(remoteFileNameA);**
            fos = new FileOutputStream(inFile);
            try {
                fileInfo.setStatus(2);
                filService.downloadInsert(fileInfo);
            } catch (Exception e) {
                throw new RuntimeException("插入数据库失败!", e);
            }
            boolean flag2 = FtpClientUtil.connectserver(CBS_FTP_SERVER_IP, CBS_FTP_PORT,
                    CBS_FTP_USERNAME, CBS_FTP_PASSWD, CBS_FTP_DIRECTORY);
            if (!flag2) {
                System.out.println("服务器连接失败");
                return "fail";
            }
            os = ftpClient.put(remoteFileNameB);
            byte[] b = new byte[1024];
            int c;
            while ((c = is.read(b)) != -1) {
                fos.write(b, 0, c);
                os.write(b, 0, c);
            }
            try {
                fileInfo.setStatus(1);
                FileService.uploadUpdate(fileInfo);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return md.getFileMD5String(inFile);
        } catch (IOException e) {
            throw new RuntimeException("文件上传或下载发生错误!", e);
        } finally {
            if (is != null)
                is.close();
            if (os != null)
                os.close();
            if (fos != null)
                fos.close();
            if (inFile.exists())
                inFile.delete();
        }
    }

求大神给点建议。PS:有同样问题的：http://www.myexception.cn/j2se/16991.html也没有得到解决。我在别的ftp上是可以的，但是在我们自带的ftp上不行。可能是ftp模式设置上的问题。