•  20-09-2022
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Domanda

I'm having some problems using CDI with Tommahawk Myfaces when trying to create a JSF page to upload a file. Referring to this question it looks as though Tommahawk MyFaces isn't compatible with CDI but is this correct?

My Bean is like this:

@ManagedBean
@RequestScoped
public class Bean {
private UploadedFile uploadedFile;

public void submit() throws IOException {
    String fileName = FilenameUtils.getName(uploadedFile.getName());
    String contentType = uploadedFile.getContentType();
    byte[] bytes = uploadedFile.getBytes();

    // Now you can save bytes in DB (and also content type?)

    FacesContext.getCurrentInstance().addMessage(null, 
        new FacesMessage(String.format("File '%s' of type '%s' successfully uploaded!", fileName, contentType)));
    }

    public UploadedFile getUploadedFile() {
        return uploadedFile;
    }

    public void setUploadedFile(UploadedFile uploadedFile) {
        this.uploadedFile = uploadedFile;
    }
}

But as soon as I replace @ManagedBean and @RequestScoped with @Named or @Model I get the following warning when deploying:

WELD-001529 An InjectionTarget implementation is created for a class org.apache.myfaces.webapp.filter.TomahawkFacesContextFactory which does not have any appropriate constructor.

And when I upload a file with the following JSF page, the value of UploadedFile is null when I use @Named or @Model. but not with @ManagedBean' and@RequestScope. This is the.xhtml` file and I do use tommahawk Myfaces:

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:t="http://myfaces.apache.org/tomahawk"
    xmlns:ui="http://java.sun.com/jsf/facelets">
    <h:head>
        <title>Tomahawk file upload demo</title>
    </h:head>
    <h:body>
        <h:form enctype="multipart/form-data">
            <t:inputFileUpload value="#{bean.uploadedFile}" />
            <h:commandButton value="submit" action="#{bean.submit()}" />
            <h:messages />
        </h:form>
    </h:body>
</html>

So I assume CDI does not like the tomahawk library as there is no default constructor?

È stato utile?

Soluzione

Looking at 'Begginning Java EE 7' it specifies that CDI 1.1 treats any class as a CDI bean which statifies (amongst other things) :

It has a default constructor with no parameters with no parameters , or it declares a constructor annotated @Inject.

It looks as though TomahawkFacesContextFactory doesn't fulfil this requirement.

** EDIT ** The above seems to be confirmed in the CDI specification here. I've switched to PrimeFaces too and again this has similar problems with CDI however I not on their announcement here that:

PrimeFaces 5.0 will ship with a new component model supported by annotation, and CDI compatible (or Spring or Guice!).

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