如何在android中使用IntentService停止下载文件

Question

我正在尝试使用IntentService从app服务器下载文件。当我想完全下载文件时它工作正常。但我想在下载过程中取消文件下载。但它失败了。我试图阻止IntentService，但服务没有停止。之后，我试图关闭HttpConnectionUrl提供的InputStream。然后是生成错误。请帮我解决这个问题。 请不要提出重复的问题。

   @Override
    protected void onHandleIntent(Intent intent) {
            final String url = intent.getStringExtra(ConstantUtils.EXTRA_URL);
            mOutputFileName = (File) intent.getSerializableExtra(ConstantUtils.EXTRA_FILE_NAME);
            mHttpURLConnectionUtil = new HttpURLConnectionUtil();
            mHttpURLConnectionUtil.setOnDownloadProgress(this);
            try {
                mHttpURLConnectionUtil.downloadFile(url, mOutputFileName);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }



    public void downloadFile(String url, File outputFile) throws IOException {

        URL u = new URL(url);
        URLConnection conn = u.openConnection();
        int contentLength = conn.getContentLength();

        mInputStream = new DataInputStream(u.openStream());
        mOutputStream = new DataOutputStream(new FileOutputStream(outputFile));

        byte[] buffer = new byte[CONTENT_LENGTH];
        int count;
        int total = 0;
        while ((count = mInputStream.read(buffer)) != -1) {
            total += count;
            mOutputStream.write(buffer, 0, count);
        }
        mOutputStream.write(buffer);
        closeStream();
    }

    private void closeStream() throws IOException {
        if (mInputStream != null) {

            mInputStream.close();
        }
        if (mOutputStream != null) {
            mOutputStream.flush();
            mOutputStream.close();
        }
    }

当我尝试关闭输入流时，获得以下异常。

java.lang.NullPointerException: Attempt to read from field 'int com.android.okio.Segment.limit' on a null object reference
                                                                     at com.android.okio.OkBuffer.write(OkBuffer.java:574)
                                                                     at com.android.okio.OkBuffer.read(OkBuffer.java:610)
                                                                     at com.android.okio.RealBufferedSource.read(RealBufferedSource.java:56)
                                                                     at com.android.okhttp.internal.http.HttpConnection$FixedLengthSource.read(HttpConnection.java:465)
                                                                     at com.android.okhttp.internal.Util.skipAll(Util.java:227)
                                                                     at com.android.okhttp.internal.http.HttpConnection.discard(HttpConnection.java:235)
                                                                     at com.android.okhttp.internal.http.HttpConnection$FixedLengthSource.close(HttpConnection.java:487)
                                                                     at com.android.okio.RealBufferedSource.close(RealBufferedSource.java:204)
                                                                     at com.android.okio.RealBufferedSource$1.close(RealBufferedSource.java:187)
                                                                     at java.io.FilterInputStream.close(FilterInputStream.java:64)
                                                                     at com.meditation.minute.utils.HttpURLConnectionUtil.closeStream(HttpURLConnectionUtil.java:59)
                                                                     at com.meditation.minute.utils.HttpURLConnectionUtil.cancelDownloading(HttpURLConnectionUtil.java:68)
                                                                     at com.meditation.minute.service.DownloadAudioIntentService$1$1.run(DownloadAudioIntentService.java:38)