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<s:textfield labelkey="%{getText("postalCode.label")}" name="postalCode"/>

The expression language (OGNL) lets us call methods and evaluate properties. The method getText is provided by ActionSupport, which is the base class for most Actions. Since the Action is on the stack, we can call any of its methods from an expression, including getText.

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<s:select labelkey="%{getText("state.label")}" name="state" multiple="true"/>

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<s:select labelkey="%{getText("state.label")}" name="state" multiple="%{true}"/>

<s:select labelkey="%{getText("state.label")}" name="state" multiple="allowMultiple"/>

<s:select labelkey="%{getText("state.label")}" name="state" multiple="%{allowMultiple}"/>

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Most often, the value attribute is set automatically, since name attribute usually tells the framework which property to call to set the value. But, if there is a reason to set the value directory directly, be advised that value is an Object NOT a String.

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<s:textfield labelkey="%{getText("state.label")}" name="state" value="CAca"/>

If a textfield is passed the value attribute "CAca", the framework will look for a property named getCa. Generally, this is not what we mean. What we mean to do is pass a literal String. In the expression language, literals are placed within quotes

<s:textfield labelkey="%{getText("state.label")}" name="state" value="%{'CAca'}" />

Another approach would be to use the idiom value="'CAca'", but, in this case, using the expression notation is recommended.

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1. All String attribute types are parsed for the "%{ ... }" notation.
2. All non-String attribute types are not parsed, but evaluated directly as an expression
3. The exception to rule #2 is that if the non-String attribute uses the escape notion "{%{}", the notation is ignored as redundant, and the content evaluated.

Expression Language Notations

<p>Username: ${user.username}</p>

<s:textfield name="username"/>

<s:url id="es" action="Hello">
  <s:param name="request_locale">
    es
  </s:param>
</s:url>
<s:a href="%{es}">Espanol</s:a>

<s:property
  value="#session.user.username" />

<s:select
  label="FooBar" name="foo"
  list="#{'username':'trillian',
    'username':'zaphod'}" />

Disallowed property names

The following names of property are disallowed:

• parameters
• application
• session
• struts
• request
• servletRequest
• servletResponse

The below code will not work:

<s:iterator value="parameters"/>

public class MyAction {

    private String[] parameters;

    public String[] getParameters() {
        return parameters;
    }

}

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