使用HTTP从Java客户端上传Java文件

我的客户机代码是用java编写的。它根据请求将文件上传到不同的服务器。这些请求在印度到美国、美国到英国等国家之间传递。此外，有时文件大到2GB。我当前的代码是无效的，因为它上传文件的速度很慢，并且需要您提供1GB的堆空间，即使只上传60MB的文件

    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
    int maxBufferSize = 1 * 1024 * 1024;
    //System.out.println("Uploading the file");
    String responseFromServer = "";       
    String urlString = "http://stcss.us.com:8888/codesign/UploadServlet";       


    try {
        //------------------ CLIENT REQUEST
        FileInputStream fileInputStream = 
            new FileInputStream(new File(exsistingFileName));
        int file_size = fileInputStream.available();

        if (file_size > 1000 * 1024 * 1024) {
            System.out.println("File Size  Error\n Max Size allowed is 500MB");
            System.exit(1);
        }

        // open a URL connection to the Jsp
        URL url = new URL(urlString);
        // Open a HTTP connection to the URL
        conn = (HttpURLConnection)url.openConnection();
        // Allow Inputs
        conn.setDoInput(true);

        // Allow Outputs
        conn.setDoOutput(true);
        // Don't use a cached copy.
        conn.setUseCaches(false);
        // Use a post method.
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("Content-Type", 
                                "multipart/form-data;boundary=" + 
                                boundary);
    //conn.setRequestProperty("Accept", "application/octet-stream");
    conn.setRequestProperty("password", password);
        conn.setRequestProperty("signingParameters", signingParameters);
        dos = new DataOutputStream(conn.getOutputStream());
        dos.writeBytes(twoHyphens + boundary + lineEnd);
        dos.writeBytes("Content-Disposition: form-data; name=\"upload\";" + 
                       " filename=\"" + exsistingFileName + "\"" + 
                       lineEnd);
        dos.writeBytes(lineEnd);
        // create a buffer of maximum size
        bytesAvailable = fileInputStream.available();
        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        buffer = new byte[bufferSize];
        // read file and write it into form...
        bytesRead = fileInputStream.read(buffer, 0, bufferSize);
        while (bytesRead > 0) {
            //   System.out.println ("file size is"+file_size+"avaiable is"+bytesAvailable);
            dos.write(buffer, 0, bufferSize);
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
        // close streams
        fileInputStream.close();
        dos.flush();
        dos.close();
    } catch (MalformedURLException ex) {
        System.out.println("From CLIENT CLIENT REQUEST Malformed:" + ex);
        System.exit(0);
    } catch (IOException ioe) {
        System.out.println("From CLIENT CLIENT REQUEST:" + ioe);
        System.exit(0);
    }

---

我可以通过哪些方式更改此代码以加快上载速度，并为相当小的文件消除堆空间？服务器端是否需要更改某些内容？我在服务器端使用apache commons fileupload。

为什么不使用Http组件之类的东西，这样就不必像其他人以前那样做了；我听说java.nio提供了更快的上传速度。这是真的吗？如何使用它？