Adding action methods to a composite component

问题

I am learning about composite components with JSF 2.0 and i want my component to be able to trigger methods from backing beans, so i created a simple example, but something is wrong.

This is the component i created:

<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:h="http://java.sun.com/jsf/html"
xmlns:composite="http://java.sun.com/jsf/composite">

<composite:interface>
        <composite:attribute name="attribute1"/>
        <composite:attribute name="attribute2"/>
        <composite:attribute name="actionBtnText"/>
        <composite:attribute name="actionMethod" method-signature="java.lang.String action()"/>
</composite:interface>

<composite:implementation>
    <h:form>
            <h:inputText value="#{cc.attrs.attribute1}"/>
            <br/>
            <h:inputText value="#{cc.attrs.attribute2}"/>
            <br/>
            <h:commandButton action="#{cc.attrs.actionMethod}" value="#{cc.attrs.actionBtnText}"/>          
    </h:form>

</composite:implementation> 

</html>

This is how i use it in a JSF page

<html xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:custom="http://java.sun.com/jsf/composite/custom">

...

    <h:body>
    <custom:demoCustomComponent attribute1="#{demoBB.value1 }" attribute2="#{demoBB.value2 }" actionBtnText="Button text!" actionBtn="#{demoBB.act}"/>
    </h:body>

And this is the backing bean that gives support to the page where the component is

@Named("demoBB")
@RequestScoped
public class DemoBB {

    private String value1;
    private String value2;
    public String getValue1() {
        return value1;
    }

    public String act() {
        System.out.println("Input 1: " + value1 + "\nInput 2: " + value2);
        return null;
    }

    //Getters and setters
    public void setValue1(String value1) {
        this.value1 = value1;
    }
    public String getValue2() {
        return value2;
    }
    public void setValue2(String value2) {
        this.value2 = value2;
    }   
}

The component seems to render fine, but when i press the button i get an exception that says:

javax.faces.FacesException: Unable to resolve composite component from using page using EL expression '#{cc.attrs.actionMethod}'

Did i make any mistake in the interface or implementation of the component? Why doesn't work?

回答1:

You definied the action method using attribute name actionBtn:

<custom:demoCustomComponent ... actionBtn="#{demoBB.act}"/>

but you're expecting it to be the attribute name actionMethod:

<composite:attribute name="actionMethod" method-signature="java.lang.String action()"/>

Align it. They should be the same.

来源：https://stackoverflow.com/questions/7806831/adding-action-methods-to-a-composite-component

标签

java

jsf

jsf-2

facelets

composite-component