URLConnection不允许我访问有关Http错误的数据（404,500等）

简单：

URLConnection connection = url.openConnection();InputStream is = connection.getInputStream();if (connection instanceof HttpURLConnection) {   HttpURLConnection httpConn = (HttpURLConnection) connection;   int statusCode = httpConn.getResponseCode();   if (statusCode != 200 ) {     is = httpConn.getErrorStream();   }}

您可以参考Javadoc进行解释。我将处理此问题的最佳方法如下：

URLConnection connection = url.openConnection();InputStream is = null;try {    is = connection.getInputStream();} catch (IOException ioe) {    if (connection instanceof HttpURLConnection) {        HttpURLConnection httpConn = (HttpURLConnection) connection;        int statusCode = httpConn.getResponseCode();        if (statusCode != 200) { is = httpConn.getErrorStream();        }    }}