Android 获取缩略图

public void getMiniThumb(HttpServletResponse resp) {
		
		OutputStream out;
		
		try {
			
			out = resp.getOutputStream();

			Cursor c = _resolver.query(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, null, null, null, null);
			
			while (c.moveToNext()) {
				for (int i = 0; i < c.getColumnCount(); i++) {
					Log.i("getMiniThumb", c.getColumnNames()[i] + "=" + c.getString(i));
				}
				Log.i("getMiniThumb", "-------------------------------------------------------------------");
			}

			c = _resolver.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null);
			
			while (c.moveToNext()) {
				for (int i = 0; i < c.getColumnCount(); i++) {
					Log.i("getMiniThumb", c.getColumnNames()[i] + "=" + c.getString(i));
				}
				Bitmap bitmap = MediaStore.Images.Thumbnails.getThumbnail(_resolver, c.getLong(0), MediaStore.Images.Thumbnails.MICRO_KIND, null);
				if (bitmap != null) {
					Log.i("getMiniThumb", "bitmap is " + bitmap.toString());
					bitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
					out.flush();
					out.write(NEXT_TAG.getBytes());
					out.flush();
				} else {
					Log.i("getMiniThumb", "bitmap is " + null);
				}
				Log.i("getMiniThumb", "-------------------------------------------------------------------");
			}


			out.close();
			
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}