使用多部分实体实现 HttpComponent 的 HttpAsyncClient

Question

我需要一些帮助，说明如何将 HttpAsyncClient 与多部分实体一起使用。基本上我正在尝试使用 HttpAsyncClient 将文件（字节 []）的内容作为多部分正文上传。 我如何使用它的示例：

    CloseableHttpAsyncClient httpAsyncClient = HttpAsyncClients.createDefault();
    httpAsyncClient.start();

    MultipartEntityBuilder reqEntity = MultipartEntityBuilder.create();
    reqEntity.addPart("file",new ByteArrayBody(Base64.decodeBase64(fileContent),"");
    reqEntity.addPart("fileSize",new StringBody("1234"));
    reqEntity.addPart("fileName",new StringBody("xyz.txt"));
    reqEntity.addPart("fileType",new StringBody("text/plain"));
    reqEntity.addPart("SEQ_NUM",new StringBody("23432"));

    HttpPost httppost = new HttpPost(endpointUrl);
    httppost.setEntity(reqEntity.build());

    Future<HttpResponse> future = httpAsyncClient.execute(httppost, null);
    httpAsyncClient.close();

以下是为此实施添加到项目中的 Pom 依赖项：

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpasyncclient</artifactId>
  <version>4.0.2</version>
</dependency>
<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpmime</artifactId>
  <version>4.3.6</version>
</dependency>

现在，我被阻止在抛出以下异常的地方：

java.util.concurrent.ExecutionException：java.lang.UnsupportedOperationException：多部分表单实体未实现#getContent()

我在 Internet 上进行了大量搜索，但几乎找不到有关新 HttpAsyncClient 实现的详细信息。我发现一些用户被问过类似的问题，但没有一个解决方案对我有用。

[HttpAsyncClient 多部分实体不起作用？] 在下面的链接中，用户建议使用 BufferedHttpEntity 包装 MultipartEntity 实例。所以，我更新了代码如下（不确定它是否正确）但仍然是同样的异常。

    CloseableHttpAsyncClient httpAsyncClient = HttpAsyncClients.createDefault();
    httpAsyncClient.start();

    MultipartEntityBuilder reqEntity = MultipartEntityBuilder.create();
    reqEntity.addPart("file",new ByteArrayBody(Base64.decodeBase64(fileContent),"");
    reqEntity.addPart("fileSize",new StringBody("1234"));
    reqEntity.addPart("fileName",new StringBody("xyz.txt"));
    reqEntity.addPart("fileType",new StringBody("text/plain"));
    reqEntity.addPart("SEQ_NUM",new StringBody("23432"));

    HttpPost httppost = new HttpPost(endpointUrl);
    httppost.setEntity(new BufferedHttpEntity(reqEntity.build()));


    Future<HttpResponse> future = httpAsyncClient.execute(httppost, null);
    httpAsyncClient.close();

感谢您帮助确定原因。

参考资料：

http://mail-archives.apache.org/mod_mbox/hc-httpclient-users/201311.mbox/%3c13034392.132.1384195516775.JavaMail.Hal@Harold-Rosenbergs-MacBook-Pro.local%3e

http://mail-archives.apache.org/mod_mbox/hc-httpclient-users/201206.mbox/%3C1339240012.2405.12.camel@ubuntu%3E

Answer 1

MultipartFormEntity 不能异步使用。一种选择是将实体写入 ByteArrayOutputStream 并从中创建一个 NByteArrayEntity 。

    File file = new File(filePath);
    ByteArrayBody body;
    body = new ByteArrayBody(FileUtils.readFileToByteArray(file), file.getName());

    HttpEntity mEntity = MultipartEntityBuilder.create()
            .setBoundary("-------------" + boundary)
            .addPart("file", body)
            .build();

    ByteArrayOutputStream baoStream = new ByteArrayOutputStream();      
    mEntity.writeTo(baoStream);

    HttpEntity nByteEntity = new NByteArrayEntity(baoStream.toByteArray(), ContentType.MULTIPART_FORM_DATA);
    httppost.setEntity(nByteEntity );