httpurlConnection.getContentLength（）返回-1

Question

我想在此IP中从互联网上下载图片： http://redsonic.skyf.ir/testdownload.jpg

但我的httpurlConnection.getContentLength()返回-1。

这是我的代码：

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();

但是当我从互联网上下载其他图片时，它可以工作。

怎么可能？

Answer 1

只需删除行：httpConnection.setDoOutput(true); 或设置为

Thanks EJP

Answer 2

没有错。我试过我的电脑。 httpurlConnection.getContentLength（）返回847.如果请求过多，则可能超过了最大连接数。