Head First Servlets and JSP, 2nd Edition

What can be in a tag body

A tag can have a body only if the <body-content> element for this tag is not configured with a value of empty. The <body-content> element can be one of either three or four values, depending on the type of tag.

<body-content>empty</body-content>

Note

The tag must NOT have a body.

<body-content>scriptless</body-content>

Note

The tag must NOT have scripting elements (scriptlets, scripting expressions, and declarations), but it CAN have template text and EL and custom and standard actions.

<body-content>tagdependent</body-content>

Note

The tag body is treated as plain text, so the EL is NOT evaluated and tags/actions are not triggered.

<body-content>JSP</body-content>

Note

The tag body can have anything that can go inside a JSP.

THREE ways to invoke a tag that can’t have a body

Each of these are acceptable ways to invoke a tag configured in the TLD with <body-content>empty</body-content>.

1. An empty tag

   

2. A tag with nothing between the opening and closing tags

   

3. A tag with only <jsp:attribute> tags between the opening and closing tags

   <mine:advice>
      <jsp:attribute name="user">${userName}</jsp:attribute>
   </mine:advice>

   Note

   The <jsp:attribute> tag is the ONLY thing you can put between the opening and closing tags of a tag with a <body-content> of empty! It’s just an alternate way to put ...