TagLib application in JSP (4-1)

The key part is as follows. Process tags. In fact, in many cases, we use the provided taglib.

Other people/companies have completed tag and processing. After packaging, all we need to do is apply it in our jsp.

But when we make a taglib, We need to write this part of tag handler.

Here, only the insert tag mentioned in the above file is used. Other values are not described in detail to avoid duplication.

=============================== InsertTag. java ==================================

/*

* $ Id: InsertTag. java, v 1.13 2000/03/04 02:54:57 brydon Exp $

* Copyright 1999 Sun Microsystems, Inc. All rights reserved.

* Copyright 1999 Sun Microsystems, Inc. Tous droits Ré servé s.

*/

Package com. sun. estore. taglib;

Import javax. servlet. jsp. JspTagException;

Import javax. servlet. jsp. tagext. TagSupport;

Import com. sun. estore. util. Debug;

/**

* This class is an easy interface to the JSP template or other

* Text that needs to be inserted.

* @ Author Greg Murray

*/

Public class InsertTag extends TagSupport {

Private boolean directInclude = false;

Private String parameter = null;

Private String templateName = null;

Private Template template = null;

Private TemplateParameter templateParam = null;

/**

* Default constructor

*/

Public InsertTag (){

Super ();

}

Public void setTemplate (String templateName ){

This. templateName = templateName;

}

Public void setParameter (String parameter ){

This. parameter = parameter;

}

Public int doStartTag (){

Try {

If (templateName! = Null ){

Template = (Template) pageContext. getRequest (). getAttribute ("template ");

}

} Catch (NullPointerException e ){

Debug. println ("Error extracting template from session:" + e );

}

If (parameter! = Null & template! = Null) templateParam = (TemplateParameter) template. getParam (parameter );

If (templateParam! = Null) directInclude = templateParam. isDirect ();

Return SKIP_BODY;

}

Public int doEndTag () throws JspTagException {

Try {

PageContext. getOut (). flush ();

} Catch (Exception e ){

// Do nothing

}

Try {

If (directInclude & templateParam! = Null ){

PageContext. getOut (). println (templateParam. getValue ());

} Else if (templateParam! = Null ){

If (templateParam. getValue ()! = Null) pageContext. getRequest (). getRequestDispatcher (templateParam. getValue (). include (pageContext. getRequest (), pageContext. getResponse ());

}

} Catch (Throwable ex ){

Ex. printStackTrace ();

}

Return EVAL_PAGE;

}

}

You can see. InsertTag. java inherits the javax. servlet. jsp. tagext. TagSupport class because some interfaces are defined in TagSupport.