httpurlConnection.getContentLength（）返回-1

Question

我想使用以下IP從互聯網下載圖片： http ： //redsonic.skyf.ir/testdownload.jpg

但是我的httpurlConnection.getContentLength()返回-1。

這是我的代碼：

URL url = new URL(downloadPath);
HttpURLConnection httpConnection =(HttpURLConnection) url.openConnection();
httpConnection.setRequestMethod("GET");
httpConnection.setDoOutput(true);
httpConnection.connect();

File file = new File(filePath);
OutputStream outputStream = new FileOutputStream(file);

InputStream inputStream = httpConnection.getInputStream();
byte[] buffer = new byte[8*1024];
int len=0;
int downloadsize = 0;
int filesize = httpConnection.getContentLength();
while ((len=inputStream.read(buffer))>0)
{
    outputStream.write(buffer,0,len);
    downloadsize += len;
    float persent = (float) downloadsize/filesize;
    Log.i("***","downloadsize="+downloadsize + "   filesize="+filesize+"    percent = "+persent);
}
//outputStream.flush();
outputStream.close();

但是，當我從互聯網上下載其他圖片時，它可以工作。

這怎么可能？

Answer 1

只需刪除以下行： httpConnection.setDoOutput(true); 或設置為false

感謝EJP

Answer 2

沒有錯。 我已經試過我的電腦了。 httpurlConnection.getContentLength（）返回847。如果發出過多請求，則可能已超過最大連接數。