Checking attribute exists in JSP

Question

I have some classes which extends a superclass, and in the JSP I want to show some attributes of these classes. I only want to make one JSP, but I don\'t know in advance if the

Answer 1

You can readily create a custom function to check for the property, as per vivin's blog post.

In short, if you already have your own taglib its just a matter of creating a static 'hasProperty' method...

import java.beans.PropertyDescriptor;
import org.apache.commons.beanutils.PropertyUtils;

...

public static boolean hasProperty(Object o, String propertyName) {
    if (o == null || propertyName == null) {
        return false;
    }
    try
    {
      return PropertyUtils.getPropertyDescriptor(o, propertyName) != null;
    }
    catch (Exception e)
    {
      return false;
    }
}

...and adding five lines to your TLD...

    hasProperty
    my.package.MyUtilClass
    boolean hasProperty(java.lang.Object,
        java.lang.String)
    

... and calling it in your JSP