how to put try catch to an event method in order to customise the catch java

Question

I have created a method to handle uploading of files when using the p:fileupload tag of PrimeFaces:

public void handleFileUpload(FileUploadEvent event) throws IOException { 
    FacesContext.getCurrentInstance()
        .getExternalContext()
        .getSessionMap().put("limage", event.getFile());        
}

But when testing this code I get an exception:

 GRAVE: C:\tmp\upload_6d3af437_13dda559a63__8000_00000082.tmp (Le fichier spécifié est introuvable)
java.io.FileNotFoundException: C:\tmp\upload_6d3af437_13dda559a63__8000_00000082.tmp (Le fichier spécifié est introuvable)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:120)
    at org.apache.commons.fileupload.disk.DiskFileItem.readObject(DiskFileItem.java:719)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at java.util.HashMap.readObject(HashMap.java:1030)
    at sun.reflect.GeneratedMethodAccessor105.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1666)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1322)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at java.util.HashMap.readObject(HashMap.java:1030)
    at sun.reflect.GeneratedMethodAccessor105.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
    at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at com.sun.faces.renderkit.ClientSideStateHelper.doGetState(ClientSideStateHelper.java:255)
    at com.sun.faces.renderkit.ClientSideStateHelper.getState(ClientSideStateHelper.java:198)
    at com.sun.faces.renderkit.ResponseStateManagerImpl.getState(ResponseStateManagerImpl.java:100)
    at com.sun.faces.application.view.StateManagementStrategyImpl.restoreView(StateManagementStrategyImpl.java:227)
    at com.sun.faces.application.StateManagerImpl.restoreView(StateManagerImpl.java:188)
    at com.sun.faces.application.view.ViewHandlingStrategy.restoreView(ViewHandlingStrategy.java:123)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.restoreView(FaceletViewHandlingStrategy.java:453)
    at com.sun.faces.application.view.MultiViewHandler.restoreView(MultiViewHandler.java:148)
    at com.ocpsoft.pretty.faces.application.PrettyViewHandler.restoreView(PrettyViewHandler.java:109)
    at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:192)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:116)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.ocpsoft.pretty.PrettyFilter.doFilter(PrettyFilter.java:126)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

In order to help track down this exception, I wrapped my custom logic in a try/catch block, with a handler in the catch block that should help me determine when an exception is caught. But the catch is not being called:

public void handleFileUpload(FileUploadEvent event) throws IOException{
    try {
        FacesContext.getCurrentInstance()
           .getExternalContext()
           .getSessionMap().put("limage", event.getFile());
    } catch(Exception e) {
        System.out.println("i am in catch ");
        e.printStackTrace();
    }       
}

I think the problem is not in the instructions, but might be occurring before the instructions are run. Here is my UI code:

<p:fileUpload   mode="advanced" auto="true"
    fileUploadListener="#{articlesMB.handleFileUpload}"  />

How can I fix the error? Thanks.

Answer 1

The getFile doesn't throw exception. The code you show just puts the file into a session map. Exception is thrown somewhere else where the file object is get used.

As I see from the stacktrace - it happens when the session tries to get deserialized between requests. You should store the file somewhere else, because the file is deleted by the framework right after multipart http request completes.