下載網絡文件HttpURLConnection.getContentLength()大小爲 0

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

conn.setRequestProperty("Accept-Encoding", "identity");    // 加上這句話解決問題

conn.connect();

int length = conn.getContentLength();

InputStream is = conn.getInputStream();

來自爲知筆記(Wiz)