java - 使用 HttpUrlConnection 发送图像文件时出现 HTTP_BAD_REQUEST 错误

Question

我在使用 httpurlconnection 将图像发送到我的服务器时遇到问题。我已阅读Android documentation另一个 HttpUrlconnection implementation但我不知道哪里做错了，因为我收到了 HTTP_BAD_REQUEST 错误代码(400)。我在下面的代码中缺少什么重要的东西？

我的响应代码总是返回 400，但我的链接没问题，因为我能够使用 httpclient 实现此目的

 link = "my link.com";

 try {
   URL   url = new URL(link);

   connection = (HttpURLConnection)url.openConnection();
   connection.setRequestMethod("POST");
   connection.setDoOutput(true);
   connection.setUseCaches(false);
   connection.setChunkedStreamingMode(0);
   connection.setRequestProperty("Content-Type", "image/jpeg");

   BufferedOutputStream outputStream = new BufferedOutputStream(connection.getOutputStream());
   FileInputStream stream = new FileInputStream(file);
   byte[] buffer = new byte[1024];
   int bytesRead;
   while ((bytesRead =stream.read(buffer ,0 ,buffer.length)) != -1){
            outputStream.write(buffer);
            outputStream.flush();
   }
  outputStream.flush();

  responseCode = connection.getResponseCode();

Answer 1

我认为问题在于图像如何添加到输出流。所有连接配置步骤看起来都不错。

我最近尝试了这个方法，效果很好:

https://vikaskanani.wordpress.com/2011/01/11/android-upload-image-or-file-using-http-post-multi-part/

包装在 AsyncTask 中也是一个好习惯。我注意到 MultipartEntity 现已弃用，但您可以用 MultipartEntityBuilder 替换。

更新

要监听文件上传事件并更新进度条，您可以重写任何 HttpEntity 实现的 writeTo 方法，并在写入输出流时计算字节数。

DefaultHttpClient httpclient = new DefaultHttpClient();
try {
   HttpPost httppost = new HttpPost("http://www.google.com/sorry");

   MultipartEntity outentity = new MultipartEntity() {

    @Override
    public void writeTo(final OutputStream outstream) throws IOException {
        super.writeTo(new CoutingOutputStream(outstream));
    }

   };
   outentity.addPart("stuff", new StringBody("Stuff"));
   httppost.setEntity(outentity);

   HttpResponse rsp = httpclient.execute(httppost);
   HttpEntity inentity = rsp.getEntity();
   EntityUtils.consume(inentity);
} finally {
    httpclient.getConnectionManager().shutdown();
}

static class CoutingOutputStream extends FilterOutputStream {

    CoutingOutputStream(final OutputStream out) {
        super(out);
    }

    @Override
    public void write(int b) throws IOException {
        out.write(b);
        System.out.println("Written 1 byte");
    }

    @Override
    public void write(byte[] b) throws IOException {
        out.write(b);
        System.out.println("Written " + b.length + " bytes");
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        out.write(b, off, len);
        System.out.println("Written " + len + " bytes");
    }

}

更新 如果您想根据 http 进度更新进度条，此链接提供了一个很好的示例

Link