通过 HTTP 表单上传文件，通过 MultipartEntityBuilder，带有进度条

Question

短版 - org.apache...MultipartEntity 已弃用，其升级版MultipartEntityBuilder 在我们的在线论坛中的代表性不足。让我们解决这个问题。如何注册回调，以便我的 (Android) 应用在上传文件时显示进度条？

长版 - 这是MultipartEntityBuilder 的“缺失的简单示例”：

public static void postFile(String fileName) throws Exception {
    // Based on: https://stackoverflow.com/questions/2017414/post-multipart-request-with-android-sdk

    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost(SERVER + "uploadFile");
    MultipartEntityBuilder builder = MultipartEntityBuilder.create();        
    builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
    builder.addPart("file", new FileBody(new File(fileName)));
    builder.addTextBody("userName", userName);
    builder.addTextBody("password", password);
    builder.addTextBody("macAddress", macAddress);
    post.setEntity(builder.build());
    HttpResponse response = client.execute(post);
    HttpEntity entity = response.getEntity();

    // response.getStatusLine();  // CONSIDER  Detect server complaints

    entity.consumeContent();
    client.getConnectionManager().shutdown(); 

}  // FIXME  Hook up a progress bar!

我们需要修复 FIXME。 （一个额外的好处是上传可中断。）但是（无论我是否错了，请纠正我），所有在线示例似乎都不足。

这个http://pastebin.com/M0uNZ6SB，例如，将文件上传为“二进制/八位字节流”；不是“多部分/表单数据”。我需要真实的字段。

此示例File Upload with Java (with progress bar) 显示了如何覆盖*Entity 或*Stream。所以也许我可以告诉MultipartEntityBuilder 到.create() 一个覆盖其上传进度的实体？

因此，如果我想覆盖某些内容，并将内置流替换为每 1000 个字节发送一个信号的计数流，也许我可以扩展 FileBody 部分，并覆盖其 getInputStream 和/或writeTo.

但是当我尝试class ProgressiveFileBody extends FileBody {...} 时，我得到了臭名昭著的java.lang.NoClassDefFoundError。

所以当我在我的 .jar 文件中寻找丢失的 Def 时，有人可以检查我的数学，并指出一个我忽略的更简单的修复吗？

Answer 1

获奖代码（采用壮观的 Java-Heresy(tm) 风格）是：

public static String postFile(String fileName, String userName, String password, String macAddress) throws Exception {

    HttpClient client = new DefaultHttpClient();
    HttpPost post = new HttpPost(SERVER + "uploadFile");
    MultipartEntityBuilder builder = MultipartEntityBuilder.create();        
    builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);

    final File file = new File(fileName);
    FileBody fb = new FileBody(file);

    builder.addPart("file", fb);  
    builder.addTextBody("userName", userName);
    builder.addTextBody("password", password);
    builder.addTextBody("macAddress",  macAddress);
    final HttpEntity yourEntity = builder.build();

    class ProgressiveEntity implements HttpEntity {
        @Override
        public void consumeContent() throws IOException {
            yourEntity.consumeContent();                
        }
        @Override
        public InputStream getContent() throws IOException,
                IllegalStateException {
            return yourEntity.getContent();
        }
        @Override
        public Header getContentEncoding() {             
            return yourEntity.getContentEncoding();
        }
        @Override
        public long getContentLength() {
            return yourEntity.getContentLength();
        }
        @Override
        public Header getContentType() {
            return yourEntity.getContentType();
        }
        @Override
        public boolean isChunked() {             
            return yourEntity.isChunked();
        }
        @Override
        public boolean isRepeatable() {
            return yourEntity.isRepeatable();
        }
        @Override
        public boolean isStreaming() {             
            return yourEntity.isStreaming();
        } // CONSIDER put a _real_ delegator into here!

        @Override
        public void writeTo(OutputStream outstream) throws IOException {

            class ProxyOutputStream extends FilterOutputStream {
                /**
                 * @author Stephen Colebourne
                 */

                public ProxyOutputStream(OutputStream proxy) {
                    super(proxy);    
                }
                public void write(int idx) throws IOException {
                    out.write(idx);
                }
                public void write(byte[] bts) throws IOException {
                    out.write(bts);
                }
                public void write(byte[] bts, int st, int end) throws IOException {
                    out.write(bts, st, end);
                }
                public void flush() throws IOException {
                    out.flush();
                }
                public void close() throws IOException {
                    out.close();
                }
            } // CONSIDER import this class (and risk more Jar File Hell)

            class ProgressiveOutputStream extends ProxyOutputStream {
                public ProgressiveOutputStream(OutputStream proxy) {
                    super(proxy);
                }
                public void write(byte[] bts, int st, int end) throws IOException {

                    // FIXME  Put your progress bar stuff here!

                    out.write(bts, st, end);
                }
            }

            yourEntity.writeTo(new ProgressiveOutputStream(outstream));
        }

    };
    ProgressiveEntity myEntity = new ProgressiveEntity();

    post.setEntity(myEntity);
    HttpResponse response = client.execute(post);        

    return getContent(response);

} 

public static String getContent(HttpResponse response) throws IOException {
    BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
    String body = "";
    String content = "";

    while ((body = rd.readLine()) != null) 
    {
        content += body + "\n";
    }
    return content.trim();
}

#  NOTE ADDED LATER: as this blasterpiece gets copied into various code lineages, 
#  The management reminds the peanut gallery that "Java-Heresy" crack was there
#  for a reason, and (as commented) most of that stuff can be farmed out to off-
#  the-shelf jar files and what-not. That's for the java lifers to tool up. This
#  pristine hack shall remain obviousized for education, and for use in a pinch.

#  What are the odds??

Answer 2

非常感谢 Phlip 提供的解决方案。这是添加进度条支持的最后一步。我在 AsyncTask 中运行它 - 下面的进度使您能够将进度发布回 AsyncTask 中的方法，该方法为在 AsyncTask 中运行的类调用 AsyncTask.publishProgress()。进度条并不完全平滑，但至少它会移动。在三星 S4 上，在序言之后上传 4MB 图像文件，它正在移动 4K 块。

     class ProgressiveOutputStream extends ProxyOutputStream {
            long totalSent;
            public ProgressiveOutputStream(OutputStream proxy) {
                   super(proxy);
                   totalSent = 0;
            }

            public void write(byte[] bts, int st, int end) throws IOException {

            // FIXME  Put your progress bar stuff here!
            // end is the amount being sent this time
            // st is always zero and end=bts.length()

                 totalSent += end;
                 progress.publish((int) ((totalSent / (float) totalSize) * 100));
                 out.write(bts, st, end);
            }

Answer 3

首先：非常感谢原始问题/答案。由于 HttpPost 现在已被弃用，我对其进行了一些修改，使用来自 article 的额外输入并制作了一个微型库：https://github.com/licryle/HTTPPoster

它将整体包装在异步任务中；使用 MultipartEntityBuilder 和 HttpURLConnection 并让您监听回调。

使用方法：

1. 下载和提取
2. 在您的 build.gradle 模块文件中，添加依赖项：

dependencies 
{    
     compile project(':libs:HTTPPoster') 
}

1. 您需要一个类来实现HttpListener 接口，以便您可以收听回调。它在HTTPListener 中有四个回调：

   • onStartTransfer
   • 正在进行中
   • onFailure
   • onResponse

2. 配置 ASyncTask 并启动它。这是一个快速的用法：

HashMap<String, String> mArgs = new HashMap<>();
mArgs.put("lat", "40.712784");
mArgs.put("lon", "-74.005941");

ArrayList<File> aFileList = getMyImageFiles();

HttpConfiguration mConf = new HttpConfiguration(
    "http://example.org/HttpPostEndPoint",
    mArgs,
    aFileList,
    this, // If this class implements HttpListener
    null,  // Boundary for Entities - Optional
    15000  // Timeout in ms for the connection operation
    10000, // Timeout in ms for the reading operation
);

new HttpPoster().execute(mConf);

希望能有所帮助:) 也欢迎提出改进建议！它是最新的，我会根据需要对其进行扩展。

干杯