struts2中if标签中字符串比较的正确写法

错误写法：

<s:if test="aStringProperty == 'A'">

  Why doesn't this work when myString is equal to A?

</s:if>

正确写法：

<s:if test='aStringProperty == "A"'>

  This works!

</s:if>

<s:if test="aStringProperty == \"A\"">

  This works too!

</s:if>