•  20-09-2022
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题

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?

有帮助吗？

解决方案

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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