在RichFaces中，在使用电子邮件验证时，我收到NullPointer异常吗？

Question

BeanClass code is:

       public void validEmail(FacesContext context, UIComponent component,
                Object value) throws Exception  
       {

                  //Set the email pattern string
          Pattern p = Pattern.compile(".+@.+\\.[a-z]+");

          //Match the given string with the pattern
          Matcher m = p.matcher(email);

          //check whether match is found 
          boolean matchFound = m.matches();

          if (matchFound)
            System.out.println("Valid Email Id.");
          else
            System.out.println("Invalid Email Id.");
       }

.xhtml Code is:

<h:inputText title="Enter Email Address" value="#{registerBean.email}" id="eMail" required="true" validator="#{registerBean.validEmail}">
<rich:ajaxValidator event="oninputblur"/>

</h:inputText>
<rich:message for="eMail"/>

Exception is:

/Register.xhtml @68,138 validator="#{registerBean.validEmail}": java.lang.NullPointerException

How can i rectify this!

Answer 1

You need to validate the value which is been passed in as method argument, not the local variable email , simply because it isn't been set yet (it has first to be validated!). It will be set only after validation phase, namely the update model values phase.

So, replace

Matcher m = p.matcher(email);

by

Matcher m = p.matcher(value);