java - 删除 System.out.println ("response::"+ connection.getResponseMessage()) 后文件未上传；

Question

以下是我上传文件 GCS 的函数:

public void fileUpload(InputStream streamData, String fileName,
            String content_type) throws Exception {

    byte[] utf8Bytes = fileName.getBytes("UTF8");
    fileName = new String(utf8Bytes, "UTF8");
    URL url = new URL("http://bucketname.storage.googleapis.com"+"/"+"foldername/"+fileName);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setDoOutput(true);
    conn.setRequestMethod("PUT");
    conn.setRequestProperty("Accept", "application/x-www-form-urlencoded");
    conn.setRequestProperty("Authorization", "OAuth " + GcsToken.getAccessToken());
    conn.setRequestProperty("x-goog-meta-FileName", fileName);
    conn.setRequestProperty("x-goog-meta-ContentType", content_type);

    OutputStream os = conn.getOutputStream();

    BufferedInputStream bfis = new BufferedInputStream(streamData);
    byte[] buffer = new byte[1024];
    int bufferLength = 0;

    // now, read through the input buffer and write the contents to the file

    while ((bufferLength = bfis.read(buffer)) > 0) {
        os.write(buffer, 0, bufferLength);

    }

    System.out.println("response :: " + conn.getResponseMessage());// ?????

}

这段代码可以很好地上传文件，但是删除最后一个 Sysout 后，它不再上传文件System.out.println("响应::"+ conn.getResponseMessage());

这背后的原因是什么？

有什么帮助吗？

谢谢

Answer 1

您需要关闭 OutputStream 以表明您已完成请求正文的编写:

os.close();

您还应该检查请求的响应代码:

if (conn.getResponseCode() != HttpURLConnection.HTTP_OK) {
    // Error handling code here.
}

它之前工作的原因是因为 getResponseMessage 函数会阻塞，直到请求发送完毕并收到回复为止。如果不检查响应值，您的函数就会退出，并且 HTTP 请求可能不会完成发送。