JSF skip Required-Validation without immediate=tru

问题:

I have multiple forms, where I have mandatory fields and optional fields.

To submit such a form I require the validation on the required-attribute to be executed, which works fine. To cancel such a form I use the attribute immediate="true" on the p:commandbutton, which makes its action happen during the Apply Request Values-Phase as addressed here: How to skip validation when a specific button is clicked?

However, for large forms I want to provide the user with a Save-Button, so he can proceed later.

For just saving the current state I also want to ignore the validation of the required-attribute. However, using immediate="true" is not working, because then my save method simple saves nothing, because the JSF lifecycle never hits the "UpdateModelValues"-Phase. (Acording to http://www.javacodegeeks.com/2012/01/jsf-and-immediate-attribute-command.html )

So, how to bypass the required-check but not skip half the lifecycle?

回答1:

Each Button creates an entry inside the Param-List as long as it's member of the form. So I simple applied a check for the presence of that entry to the "required" parameter:

<h:form id="form" prependId="true">
...
<p:inputText id="someId"
    required="#{param['form:save']==null}" ... />
...
<p:commandButton id="save" value="Save" />
<p:commandButton id="submit" value="Submit" />
<p:commandButton id="cancel" value="Cancel" immediate="true" />
</h:form>

When I click "Submit" the param['form:save'] is NULL, which then turns the expression to true so the validation is executed.

When I click "Save" the param['form:save'] is NOT NULL (but empty!), which resolves to false so the validation is ignored. (Or let's say JSF thinks it is not a required field due to the expression beeing evaluated to false)

回答2:

if you want to skip validation when click on button then easly add parameter to button where you want to skip it. Example:

<p:commandButton value="button1" action="#{bean.action()}" >
   <f:param name="skipValidator" value="true"/>
</p:commandButton>

Then in validator you can read this parameter and if it is true then skip it:

@FacesValidator("com.validators.MyValidator")
public class MyValidator implements Validator{

  public void validate(FacesContext ct, UIComponent co, Object obj) throws ValidatorException { 
    if(!continueValidation()){
      return;
    }
    // validation process
  }

protected boolean continueValidation() {
    String skipValidator= FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("skipValidator");
    if (skipValidator != null && skipValidator.equalsIgnoreCase("true")) {
      return false;
    }
    return true;
  } 
}

回答3:

This is an excellent question and a very helpful answer. This approach saves a lot of hassle with immediate="true".

I'd like to add this info (but am not allowed to comment yet). Your code examples seem to require JSF 2.0 or above (correct me). If you are like me damned to use JSF 1.1/1.2 then consider these changes/additions:

<h:form id="form">
...
<p:inputText id="someId" required="#{!empty param['save']}" ... />
...
<p:commandButton id="save" value="Save" />
</h:form>

• There is no attribute prependId in JSF 1.1
• Therefore in the param[...] you must only specify the button id
• You are using a syntax ="{true and ...}" that might be a mistake (no #)?
• As you can see from your own editing history the "null or not null" logic is not very intuitive :) Thats why I immediately liked the !empty ... version when I stumbled upon it.

回答4:

An alternative to what others proposed is to use a custom BeanValidator that will validate the form if say, clicked the button with id save. Any other button not implicitly defined to perform validation will not validate but just submit your data available. Find the full nice and clean example here

回答5:

In my case I didn't find the clientId of the button in the params but I found this param['javax.faces.source'] = buttonClientId in the requestmap. The value will be the clientId of the clicked button.

回答6:

I use skipValidators for such a case (assuming all validations are skipped). Code from omnifaces

<h:form>
  <h:dataTable value="#{bean.items}" var="item">
    <h:column>
        <h:inputText value="#{item.value}" required="true" />
    </h:column>
  </h:dataTable>
  <h:commandButton value="add new row" action="#{bean.add}">
    <o:skipValidators />
  </h:commandButton>
  <h:commandButton value="save all data" action="#{bean.save}" />
  <h:messages />
</h:form>