在Android中上传大文件而不会出现内存错误

My upload code as below:

我的上传代码如下:

String end = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
try {
    URL url = new URL(ActionUrl);
    HttpURLConnection con = (HttpURLConnection) url.openConnection();
    con.setDoInput(true);
    con.setDoOutput(true);
    con.setUseCaches(false);
    con.setRequestMethod("POST");
    con.setRequestProperty("Connection", "Keep-Alive");
    con.setRequestProperty("Accept", "text/*");
    con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
    DataOutputStream ds = new DataOutputStream(con.getOutputStream());
    ds.writeBytes(twoHyphens + boundary + end);
    ds.writeBytes("Content-Disposition: form-data;" + "name=\"folder\"" + end + end);
    ds.write(SavePath.getBytes("UTF-8"));
    ds.writeBytes(end);
    ds.writeBytes(twoHyphens + boundary + end);
    ds.writeBytes("Content-Disposition: form-data;" + "name=\"Filedata\"; filename=\"");
    ds.write(FileName.getBytes("UTF-8"));
    ds.writeBytes("\"" + end);
    ds.writeBytes(end);
    FileInputStream fStream = new FileInputStream(uploadFilepath+""+FileName);
    int bufferSize = 1024;
    byte[] buffer = new byte[bufferSize];
    int length = -1;
    int pro = 0;
    while((length = fStream.read(buffer)) != -1) {
        ds.write(buffer, 0, length);
    }       
    ds.writeBytes(end);
    ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
    fStream.close();
    ds.flush();
    InputStream is = con.getInputStream();
    int ch;
    StringBuffer b = new StringBuffer();
    while((ch = is.read()) != -1) {
        b.append((char)ch);
    }
    ds.close();
}
catch(Exception e) {
    e.printStackTrace();
}
String e