Passing parameters with h:commandButton — or the equivalent

问题

I read on other threads that this does not work:

<h:commandButton value="Create New Account" 
                action="#{acctBean.doCreate}" >
   <f:param name="acctName" value="#{acctBean.handle}" />
   <f:param name="acctNo" value="#{acctBean.id}" />
</h:commandButton>

The doCreate() method will return a navigation to a "congratulations" page if it creates the account. The target page can then resolve #{param.handle} and #{param.id}.

I know this will work if I use h:commandLink instead, but I want a button, not a link. Is there any generally accepted way of doing that?

UPDATE:

Based on the first answer from @BalusC I created the following test code:

<h:commandButton value="Push Me" action="goAcctCreated" >
    <f:param name="acctName" value="This Is Account Name" />
    <f:param name="acctNo" value="1234" />
</h:commandButton>
<h:button value="Push Me #2" outcome="newAcct" >
    <f:param name="acctName" value="This Is Account Name" />
    <f:param name="acctNo" value="1234" />
</h:button>

And in the target page I have:

<p>You may now log in with the account you just created: <b>#{param['acctName']}</b>.</p>
<p>This is account number <b>#{param['acctNo']}</b>.</p>

As before, the h:commandButton does not work with a POST transaction and as BalusC said, h:button does a GET and does work.

Interestingly enough, on the POST that the h:commandbutton does it has the parameters encoded, as viewed by Firebug:

acctName    This Is Account Name
acctNo  1234
javax.faces.ViewState   8642267042811824055:-4937858692781722161
testForm    testForm
testForm:j_idt55    testForm:j_idt55

So the f:param tags are doing their job at least, but the target page doesn't resolve the EL expressions #{param[xxx]}. They also don't show up in the scoped variables report (ctrl-shift-D). Is there something I am supposed to do on the target page?

回答1:

This should work perfectly fine on JSF 2.x. Did you ever try it yourself? If it doesn't work, then you're either actually using JSF 1.x or you're sending a redirect after POST.

The other threads which you're referring to were undoubtely talking about JSF 1.x, when the <f:param> was indeed not supported on <h:commandButton>. On JSF 1.x, you would have used <f:setPropertyActionListener> instead or some shot of CSS to style the <h:commandLink> to look like a button.

E.g.

<h:commandLink styleClass="button" ...>

with

a.button {
    display: inline-block;
    background: lightgray;
    border: 1px outset lightgray;
    outline: none;
    color: black;
    text-decoration: none;
    cursor: default;
}
a.button:active {
    border-style: inset;
}

Note that in JSF 2.x you've also the opportunity to use the new <h:button> which fires a GET request instead of a POST request. This is better if you don't need to execute any bean action (i.e. your current action is just returning a plain navigation case outcome) and want the request to be idempotent.

<h:button value="Create New Account" outcome="create">
    <f:param name="acctName" value="#{acctBean.handle}" />
    <f:param name="acctNo" value="#{acctBean.id}" />
</h:button>

This will navigate to create.xhtml with the given parameters in request URL.

来源：https://stackoverflow.com/questions/7366480/passing-parameters-with-hcommandbutton-or-the-equivalent

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