Javax ClientBuilder post（）在发送到Web服务之前删除文件

Question

我试图将临时文件发送到REST风格的Web服务。我使用下面的函数来做到这一点：

private static String nlpFileUpload(String filePath) throws IOException { 
    // Check is file exists 
    File file = new File(filePath); 
    if(!file.isFile()) { 
     throw new FileNotFoundException(); 
    } 

    // Upload file to web service 
    return ClientBuilder.newClient() 
     .target(nlprestURL + "upload") 
     .request() 
     .post(
       Entity.entity(file, MediaType.APPLICATION_OCTET_STREAM) 
     ).readEntity(String.class); 
} 

的问题是，在方法.post()文件有时会从磁盘中删除，并返回FileNotFound例外：

[ERROR] [04/18/2016 19:04:35.945] [application-akka.actor.default-dispatcher-2] [TaskInvocation] java.io.FileNotFoundException: /tmp/multipartBody3655134388737861177asTemporaryFile (No such file or directory) 
javax.ws.rs.ProcessingException: java.io.FileNotFoundException: /tmp/multipartBody3655134388737861177asTemporaryFile (No such file or directory) 
at org.glassfish.jersey.client.internal.HttpUrlConnector.apply(HttpUrlConnector.java:287) 
at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:255) 
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:684) 
at org.glassfish.jersey.client.JerseyInvocation$1.call(JerseyInvocation.java:681) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:315) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:297) 
at org.glassfish.jersey.internal.Errors.process(Errors.java:228) 
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:444) 
at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:681) 
at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:437) 
at org.glassfish.jersey.client.JerseyInvocation$Builder.post(JerseyInvocation.java:343) 
at pl.edu.pwr.services.serel.SerelServiceRs.nlpFileUpload(SerelServiceRs.java:97) 
at pl.edu.pwr.services.serel.SerelServiceRs.processFile(SerelServiceRs.java:181) 
at jobs.ProcessDocuments.run(ProcessDocuments.java:54) 
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:41) 
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393) 
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) 
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) 
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) 
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) 

Caused by: java.io.FileNotFoundException: /tmp/multipartBody3655134388737861177asTemporaryFile (No such file or directory) 
at java.io.FileInputStream.open0(Native Method) 
at java.io.FileInputStream.open(FileInputStream.java:195) 
at java.io.FileInputStream.<init>(FileInputStream.java:138) 
at org.glassfish.jersey.message.internal.FileProvider.writeTo(FileProvider.java:115) 
at org.glassfish.jersey.message.internal.FileProvider.writeTo(FileProvider.java:67) 
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:265) 
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:250) 
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162) 
at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1130) 
at org.glassfish.jersey.client.ClientRequest.writeEntity(ClientRequest.java:502) 
at org.glassfish.jersey.client.internal.HttpUrlConnector._apply(HttpUrlConnector.java:388) 
at org.glassfish.jersey.client.internal.HttpUrlConnector.apply(HttpUrlConnector.java:285) 
... 19 more 

但这种异常不会总是出现。在调试过程中，我发现有时文件被发送到正确的服务，但在上面的其他时间出现异常。 我不知道这里有什么问题。该服务能够读取文件为MediaType.APPLICATION_OCTET_STREAM，但我认为问题出在客户端。为什么.post()方法在将文件发送到Web服务之前删除我的文件？

我在我的应用程序中使用Play框架2.3.9。函数由Akka调度程序调用。

Answer 1

播放临时文件的问题在于，它们在被垃圾收集时被删除。临时文件在客户端上传文件时创建，并作为MultipartFormData处理。这一定是你的代码有时候工作的原因。

要解决这个问题，您可以尝试保留对该文件的引用，以免它被垃圾收集器清理。你可以通过改变函数的定义来使用这个引用：

static String nlpFileUpload(File file) throws IOException