Java http 400使用google app engine将文件上载到blobstore时出错

我正试图用谷歌应用程序引擎blobstore上传一个文件

它应该是这样工作的：您调用BlobstoreService来获取一个上传url，并提供一个回调url。客户端被重定向到上传URL，发送数据，然后当它们完成后，它们将被重定向到回调URL，其中包含两个代表blobstore键的参数

正如我们将看到的，dev服务器的行为与生产服务器不同

在生产环境中，我的代码完成了上传，然后没有重定向回回调URL，而是得到了400个错误响应（这意味着我的请求有问题）。我如何在生产中调试它？我不知道如何打开blobstore的日志记录

因此，我尝试在本地针对dev服务器运行它。这一次如果我没有设置'content length'属性，我会得到411（content length未设置）。但如果我尝试设置该属性，就会得到“IllegalStateException:已连接”。这两种例外情况都不会对生产造成不利影响

所以我不知道下一步该去哪里。我需要让它与dev协同工作，希望我能在本地调试blobstore，或者找出为什么它在生产中不能在blobstore上工作

    public void upload(String uri, File file) throws IOException    {
    HttpURLConnection conn=null;
    HttpURLConnection conn2=null;
    FileInputStream fileInputStream = null;
    DataOutputStream dos=null;
    try {
        String lineEnd = "\r\n";
        String twoHyphens = "--";
        String boundary = "*****";
        int bytesRead, bytesAvailable, bufferSize;
        byte[] buffer;
        int maxBufferSize = 1 * 1024 * 1024; 
        // open a URL connection to the Servlet
        fileInputStream = new FileInputStream(file);
        URL url = new URL(uri);

        // Open a HTTP  connection to  the URL
        conn = (HttpURLConnection) url.openConnection();
        conn.setDoInput(true); // Allow Inputs
        conn.setDoOutput(true); // Allow Outputs
        conn.setUseCaches(false); // Don't use a Cached Copy
        conn.setInstanceFollowRedirects(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");
        conn.setRequestProperty("ENCTYPE", "multipart/form-data");
        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
//          conn.setChunkedStreamingMode(1024);
        conn.setRequestProperty("content-length", String.valueOf(file.length()));   //caused IllegalStateException "Already connected" locally, but not remotely

        log("Orignal URL: " + conn.getURL());
        //conn.connect();   //TODO duplicates url.openConnection() above?
        conn.getInputStream();  //so we can follow the redirect
        String redirectedUrl = conn.getHeaderField("Location");
        log("Redirected URL: " + redirectedUrl);
        //this is horrible and messy but let's get it working then clean it up later

        conn.disconnect();
        url = new URL(redirectedUrl);

        // Open a new HTTP  connection to  the URL
        conn2 = (HttpURLConnection) url.openConnection();
        conn2.setDoInput(true); // Allow Inputs
        conn2.setDoOutput(true); // Allow Outputs
        conn2.setUseCaches(false); // Don't use a Cached Copy
        conn2.setInstanceFollowRedirects(false);
        conn2.setRequestMethod("POST");
        conn2.setRequestProperty("Connection", "Keep-Alive");
        conn2.setRequestProperty("ENCTYPE", "multipart/form-data");
        conn2.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
        conn2.setChunkedStreamingMode(maxBufferSize);
        conn2.setRequestProperty("Content-Length", String.valueOf(file.length()));
        conn2.connect();
        dos = new DataOutputStream(conn2.getOutputStream());

        dos.writeBytes(twoHyphens + boundary + lineEnd);
        dos.writeBytes("Content-Disposition: form-data; name=\"myFile\";filename=\""+file.getName()+"\"" + lineEnd);
        dos.writeBytes(lineEnd);

        // create a buffer of  maximum size
        bytesAvailable = fileInputStream.available();

        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        buffer = new byte[bufferSize];

        // read file and write it into form...
        bytesRead = fileInputStream.read(buffer, 0, bufferSize); 

        while (bytesRead > 0) {
            dos.write(buffer, 0, bufferSize);
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);  
        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

        // Responses from the server (code and message)
        int serverResponseCode = conn2.getResponseCode();
        String serverResponseMessage = conn2.getResponseMessage();
        //we are expecting another redirect here
        log("aaaargh! 400 instead of 302! "+serverResponseCode+" to "+conn2.getHeaderField("Location"));
    }catch (IOException e)  {
        log(e.getMessage());
        throw e;
    }catch(Exception e) {
        log(e.getMessage());
        throw new IOException(e);
    }   finally {
        //close the streams //
        if (dos!=null)  {   
            try {
                dos.flush();
                dos.close();
            }catch(IOException ioe){}
        }
        if (fileInputStream!=null)
            try {
                fileInputStream.close();
            }catch(IOException ioe){}

        if (conn!=null )
            try {
                conn.disconnect();
            }catch(Exception ioe){}

        if (conn2!=null)
            try {
                conn2.disconnect();
            }catch(Exception ioe){}

    }
}

---

注意：上面的serverResponseMessage字符串从生产blobstore返回为“坏请求”

我不知道如何从Android客户端执行此操作，但我可以向您展示我们如何从javascript客户端执行此操作，因为它可能会给您一些提示

客户端非常简单（这是一个angular.js控制器），我们得到了要使用的url并上传到它

// model file upload
    $scope.onFileSelect = function ($files) {
        $scope.uploadStatus = 'loading';
        for (var i = 0; i < $files.length; i++) {
            var file = $files[i];
            console.log(file);

            $http.get('/endpoints/prototype/' + $scope.prototype.key + '/file/url')
                .success((function (data) {
                        console.log(data);

                        $scope.upload = $upload.upload({
                            url: data,
                            withCredentials: true,
                            file: file
                        })
                        .success(function (data) {
                            console.log(data);
                            $scope.prototype.modelFile = data;
                        })
                        .error(function (data, status) {
                            console.error(data);
                            $scope.uploadStatus = 'error';
                            $scope.uploadError = status;
                        });
                }))
                .error((function (data, status) {
                    console.error(data);
                    $scope.uploadStatus = 'error';
                    $scope.uploadError = status;
                }));
        }
    };

最后，上传成功后调用的端点

@RequestMapping(value = "/endpoints/prototype/{key}/file", method = RequestMethod.POST)
@ResponseBody
public String handleFileUpload(@PathVariable("key") String prototypeKey, HttpServletRequest request) {
    final Map<String, List<BlobKey>> blobs = blobstoreService.getUploads(request);
    final Map<String, List<FileInfo>> allFileInfos = blobstoreService.getFileInfos(request);

    final List<BlobKey> blobKeys = blobs.get(INPUT_FILE_NAME);
    final List<FileInfo> fileInfos = allFileInfos.get(INPUT_FILE_NAME);

    if ((blobKeys == null) || (fileInfos == null)) {
        return "You failed to upload a model file for " + prototypeKey + " because the file was empty.";
    } else if ((blobKeys.size() == 1) && (fileInfos.size() == 1)) {
        final BlobKey blobKey = blobKeys.get(0);
        final FileInfo fileInfo = fileInfos.get(0);

        final Prototype prototype = prototypeService.findByKey(prototypeKey);
        prototype.setModelFile(blobInfoFactory.loadBlobInfo(blobKey).getFilename());
        prototype.setUploadedModelFile(fileInfo.getGsObjectName());

        prototypeService.updatePrototype(prototypeKey, prototype);

        return blobInfoFactory.loadBlobInfo(blobKey).getFilename();
    } else {
        return "One and only one file is allowed to be uploaded. The related prototype is " + prototypeKey +
              ". The number of blobs is " + blobKeys.size() + ", the number of files is " + fileInfos.size();
    }
}

@RequestMapping（value=“/endpoints/prototype/{key}/file”，method=RequestMethod.POST）
@应答器
公共字符串handleFileUpload（@PathVariable（“key”）字符串原型密钥，HttpServletRequest请求）{
final Map blobs=blobstoreService.getUploads（请求）；
最终映射allFileInfos=blobstoreService.getFileInfos（请求）；
最终列表blobKeys=blobs.get（输入文件名）；
最终列表fileInfos=allFileInfos.get（输入文件名）；
if（（blobKeys==null）| |（fileInfos==null））{
return“您未能上载“+prototypeKey+”的模型文件，因为该文件为空。”；
}else if（（blobKeys.size（）=1）和&（fileInfos.size（）=1））{
final BlobKey-BlobKey=BlobKey.get（0）；
final FileInfo FileInfo=fileInfos.get（0）；
最终原型=prototypeService.findByKey（prototypeKey）；
prototype.setModelFile（blobInfoFactory.loadBlobInfo（blobKey.getFilename（））；
setUploadedModelFile（fileInfo.getGsObjectName（））；
prototypeService.updatePrototype（prototypeKey，prototype）；
返回blobInfoFactory.loadBlobInfo（blobKey.getFilename（）；
}否则{
return“只允许上传一个文件，相关原型为”+prototypeKey+
。Blob的数量为“+blobKeys.size（）+”，文件的数量为“+fileInfos.size（）”；
}
}

---

就是这样，希望它能帮助您解决您的问题。

我通过使用更高级别的API而不是我尝试使用的低级HttpConnection代码来解决这个问题

    public String uploadFile(String url, File f) throws Exception   {
    HttpClient httpClient = new DefaultHttpClient();    
    String str = "";
    HttpPost first = new HttpPost(url);  //a GET should work but I was getting 405
    HttpResponse firstResponse = httpClient.execute(first);
    str = firstResponse.getFirstHeader("Location").getValue();
    //Post image to generated url
    HttpPost second = new HttpPost(str);
    FileBody fileBody = new FileBody(f);
    MultipartEntity reqEntity = new MultipartEntity();
    reqEntity.addPart("file", fileBody);
    second.setEntity(reqEntity);
    httpClient = new DefaultHttpClient();
    HttpResponse secondResponse = httpClient.execute(second); 
    str = secondResponse.getFirstHeader("Location").getValue();
    log(str);
    return str;
}

---

此方法返回上载图像的服务URL。

正如您所说：您向客户端提供一个上载URL，然后接收一个简单的回调。这段代码是干什么用的？我正在尝试使用google app engine blobstore从android客户端上载一个文件。我怀疑您实际上没有将确切的名称-值对参数处理到后端servlet或控制器。因此你得到了这个问题。还要检查您的文件是否上载到blobstore。

    public String uploadFile(String url, File f) throws Exception   {
    HttpClient httpClient = new DefaultHttpClient();    
    String str = "";
    HttpPost first = new HttpPost(url);  //a GET should work but I was getting 405
    HttpResponse firstResponse = httpClient.execute(first);
    str = firstResponse.getFirstHeader("Location").getValue();
    //Post image to generated url
    HttpPost second = new HttpPost(str);
    FileBody fileBody = new FileBody(f);
    MultipartEntity reqEntity = new MultipartEntity();
    reqEntity.addPart("file", fileBody);
    second.setEntity(reqEntity);
    httpClient = new DefaultHttpClient();
    HttpResponse secondResponse = httpClient.execute(second); 
    str = secondResponse.getFirstHeader("Location").getValue();
    log(str);
    return str;
}