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Jsf form action

Answer 1

+2 A:

Add a property id to the template bean:

public class Template {
    private Long id; // +getter +setter
}

Instruct JSF in the faces-config to set it with #{param.id} during bean's creation:

<managed-bean>
    <managed-bean-name>template</managed-bean-name>
    <managed-bean-class>com.example.Template</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
    <managed-property>
        <property-name>id</property-name>
        <value>#{param.id}</value>
    </managed-property>
</managed-bean>

Retain the property in subsequent request by passing it through as hidden input field in the same form:

<h:inputHidden value="#{template.id}" />

Then you can access it the usual way in action method:

public String submit() {
    System.out.println("id: " + this.id);
    return null;
}

BalusC 2010-09-23 14:19:35

And what url will be after submit?

chardex 2010-09-23 14:39:19

The form's action url. Thus, the parameter will disappear. But as per your comment this wasn't the functional requirement? It would otherwise going to be a 5 times bigger answer since that's not that obvious/easy in JSF.

BalusC 2010-09-23 15:10:31

Huge thanks! If it is difficult - it is not necessary. I now understand more. In the bean object I need to load the template object from the data layer. Until then, I did it in the constructor of template bean, and then all the getters return the fields from data object, and setters - sets fields of this data object. Now, this scheme does not work, because real object identifier I get twice (two calls of setId): one from the query string, the other from the hidden field. Could you give an example of such bean? At what point does the right way to load data object from the data layer?

chardex 2010-09-23 15:33:56

Use a method which you annotate with `@Postconstruct`. It will be executed after bean's construction and all dependency (managed property) injection.

BalusC 2010-09-23 15:42:55

Thanks. I added method @PostConstruct public void init(){LOG.info("init")}, but is doesn't called. Only gettters calls are logged. jsr250-api is in classpath. Very strange.

chardex 2010-09-23 16:18:32

So you're using legacy JSF 1.1? The `@PostConstruct` was introduced in JSF 1.2, already over 4 years old. Verify if your JSF libraries comply 1.2 and your `faces-config.xml` root declaration also.

BalusC 2010-09-23 16:28:50

chardex 2010-09-23 16:40:33

It is my first web project using Java :) Sorry for such questions!

chardex 2010-09-23 16:42:03

I don't understand what version I'm using.

chardex 2010-09-23 16:56:14

MyFaces 1.1.5, so you're using the 6 year old JSF 1.1 (ouch). Since you've declared faces-config as JSF 2.0 and web.xml as Servlet 2.5 and are already using Facelets, why don't you upgrade to JSF 2.0? It offers [major](http://stackoverflow.com/questions/3623911/what-are-the-main-disadvantages-of-java-server-faces-2-0) advantages. Replace the [MyFaces](http://myfaces.apache.org) JAR's by the 2.0 ones, or just use [Mojarra 2.0](http://javaserverfaces.dev.java.net).

BalusC 2010-09-23 17:32:06

Thanks. I'm only studing JSF, so I copied and pastied maven dependencies from someone blog.

chardex 2010-09-23 17:52:57

Note that Facelets is already included in JSF 2.0. Also note that Tomahawk is not officially compatible with JSF 2.0, although most components will work. Instead of `<t:div>` you can also use `<h:panelGroup layout="block">`. It will render a `<div>`.

BalusC 2010-09-23 18:14:17

I have three new related problems: 1) after submit I don't receive id from hidden field in @PostConstruct method. I receive it later in setId(). So where I should load datalayer entity? 2) After migrating to JSF 2.0 I receive NullReferenceException after submitting command button, like in this post you have unswered: http://forums.sun.com/thread.jspa?threadID=5412526 But I don't have sessions or JDBC. It appears after loading from DB (and threre is no my code in stack trace). 3) If I use h:panelGroup insted of t:div I can't setup rendered attribute like before, but I need it.

chardex 2010-09-24 10:52:40

1) Your bean needs to be in request scope (and you should be using at least JSF 1.2). 2) NullReferenceException doesn't exist in Java. Please ask a new question with entire trace. 3) You can just keep using `rendered` attribute in `h:panelGroup`.

BalusC 2010-09-24 11:24:43

1) template is in request scope and JSF 2.0 is used. @PostScript works, but after it setId is called from <h:inputHidden value="#{template.id}" /> (as you adviced). 2) Sorry, NullReferenceException is from .NET, I mean NullPointerException. Here is new question http://stackoverflow.com/questions/3786772/jsf-2-0-nullpointerexception-exception-after-submitting-commandbutton. 3) Strange, IntelliJ IDEA 9 highlited <h:panelGroup rendered="#{template.hasErrors}"> as error (Couldn't convert #{template.hasErrors} to target class Boolean)

chardex 2010-09-24 11:57:03

1) I don't understand the problem then. 2) Okay. 3) IntelliJ is apparently not as intelligent as you think. Just ignore and run it.

BalusC 2010-09-24 11:59:18

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