Android HttpURLConnection.getContentLength() 等于 -1

默认情况下,HttpURLConnection使用gzip方式获取,要取得长度则要求http请求不要gzip压缩;

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

conn.setRequestProperty("Accept-Encoding", "identity"); // 添加这行代码

conn.connect();

int length = conn.getContentLength();