Question

我使用Android HttpURLConnection进行网络下载。这是我的代码：

    HttpURLConnection conn = null;
    try {
        conn = (HttpURLConnection) new URL("http://XXXXXXXXXX").openConnection();
        InputStream inputStream = conn.getInputStream();
        Log.d("Reflection",inputStream.getClass().getCanonicalName());

        int TOTAL_LEN = conn.getContentLength();
        byte[] buf = new byte[1024 * 8];
        int len = 0, total = 0;
        while (len != -1) {
            len = inputStream.read(buf);
            total += len;
            Log.d("Download Process:", total * 1.0 / TOTAL_LEN * 100 + "");
        }
    }catch (Exception e) {
        e.printStackTrace();
    }

由于Inputstream是一个抽象类，我使用反射来显示它的实现：inputStream.getClass().getCanonicalName()。但结果是空的。

所以我尝试inputStream.getClass()，结果是class com.android.okio.RealBufferedSource$1。

为什么呢？我怎样才能在这里找出inputstream的真实实现？

问题已解决

答案是anonymous class。我浏览了Android源代码并发现了它。位置为/external/okhttp/okio/src/main/java/okio/RealBufferedSource.java，代码如下：

public InputStream inputStream() {
  return new InputStream() {
  @Override
  public int read() throws IOException {
    if (closed) throw new IOException("closed");
    if (buffer.size == 0) {
      long count = source.read(buffer, Segment.SIZE);
      if (count == -1) return -1;
    }
    return buffer.readByte() & 0xff;
  }

  @Override
  public int read(byte[] data, int offset, int byteCount) throws IOException {
    if (closed) throw new IOException("closed");
    checkOffsetAndCount(data.length, offset, byteCount);

    if (buffer.size == 0) {
      long count = source.read(buffer, Segment.SIZE);
      if (count == -1) return -1;
    }

    return buffer.read(data, offset, byteCount);
  }

  @Override
  public int available() throws IOException {
    if (closed) throw new IOException("closed");
    return (int) Math.min(buffer.size, Integer.MAX_VALUE);
  }

  @Override
  public void close() throws IOException {
    RealBufferedSource.this.close();
  }

  @Override
  public String toString() {
    return RealBufferedSource.this + ".inputStream()";
  }
};
}

请注意，此方法返回new InputStream()并且它是匿名的。

使用inputStream.getClass（）。getCanonicalName（）但返回null？

0 个答案: