Luke Luke - 1 month ago 15
Java Question

File not found exception for temporary files

I'm building java app (Spring & JSF & PrimeFaces). I upload a file to the server, however, if I click "next" button right after the file upload ends, I get this error:

Aug 24, 2013 8:12:34 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [appServlet] in context with path [/codekata] threw exception [Request processing failed; nested exception is org.springframework.webflow.execution.repository.FlowExecutionRestorationFailureException: A problem occurred restoring the flow execution with key 'e1s3'] with root cause
java.io.FileNotFoundException: C:\Users\Luke\AppData\Local\Temp\upload__6f71235a_140b1bdd246__8000_00000011.tmp (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:138)
at org.apache.commons.fileupload.disk.DiskFileItem.readObject(DiskFileItem.java:709)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1004)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1891)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1796)
java.lang.Thread.run(Thread.java:722)


If I wait a couple of seconds, all works fine.
I assume that the upload file needs to have time to copy itself to the temporary folder, does anyone have an idea how to resolve this problem. I use Tomcat 7.

Here is my download method:

public StreamedContent getDownloadFile()
{
InputStream inputStream = new ByteArrayInputStream(selectedBook.getBookText().getText().getBytes());
return new DefaultStreamedContent(inputStream, "text/plain", selectedBook.getTitle() + ".txt", BookBean.encoding);
}


Thanks,
Luke.

Answer

Based on the stack trace, it looks like that you're storing the UploadedFile instance as a property of a class which is by itself Serializable. This is not right. You should be grabbing the uploaded file content immediately in the <p:fileUpload handleFileUpload> file upload listener method (or the submit button in case you are using <p:fileUpload mode="simple">). Store it at a more permanent location. E.g. the local disk file system, or the database, or maybe even as a byte[] bean property. And then pass the local disk file system filename, or database PK, or the byte[] around instead in order to have a handle to download the file back.

Summarized, just make sure that your Serializable backing bean is completely free of a UploadedFile property and this problem shall disappear.

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