android 获取网络图片方法 常见错误以及解决办法

private Bitmap getUrlimg(String url) throws IOException {
		Bitmap bitmap = null;
		URL imageUrl = null;
		String head = "http://114.80.209.134:13080/";
		String tureUrl = head + url;
		imageUrl = new URL(tureUrl);
		
		HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
		conn.connect();
		InputStream is = conn.getInputStream();
		BufferedInputStream bis = new BufferedInputStream(is);
		bitmap = 
		bis.close();
		is.close();

		return bitmap;
	}

以前经常用这种方式获得图片，但是今天发现当图片比较多而且大时，经常 失败，

后来发现  io流的获取没有出错，得到的是完整的io流，但是 还是失败，发现是那个 BitmapFactory.decodeStream(bis);的问题  后来改成这样，见下，可以完全解决问题。

private Bitmap getUrlimg(String url) throws IOException {
		Bitmap bitmap = null;
		URL imageUrl = null;
		String head = "http://114.80.209.134:13080/";
		String tureUrl = head + url;
		imageUrl = new URL(tureUrl);

		HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
		conn.setRequestMethod("GET");
		conn.setConnectTimeout(5 * 1000);
		conn.connect();
		InputStream is = conn.getInputStream();
		byte[] bt = getBytes(is);
		bitmap = BitmapFactory.decodeByteArray(bt, 0, bt.length);
		is.close();
		conn.disconnect();
		return bitmap;
	}
	
	private byte[] getBytes(InputStream is) throws IOException {

		ByteArrayOutputStream baos =new ByteArrayOutputStream();

		byte[] b =new byte[1024];
		int len = 0;
		while ((len = is.read(b, 0, 1024)) !=-1) {
			baos.write(b, 0, len);
			baos.flush();
		}
		byte[] bytes = baos.toByteArray();
		return bytes;
	}