There are two mechanisms for including another Web resource in a JSP page:
1- the
include directive
2-the
jsp:include element.
The
include directive is processed when the JSP page is translated into a servlet class. The effect of the directive is to insert the text contained in another file--either static content or another JSP page--in the including JSP page. You would probably use the include directive to include banner content, copyright information, or any chunk of content that you might want to reuse in another page. The syntax for the include directive is as follows:
<%@ include file="filename" %>
For example, if you want to include the file init.j
sp containing the global content you can use:-<%@ include file="init.jsp" %>
The
jsp:include element is processed when a JSP page is executed. The include action allows you to include either a static or dynamic resource in a JSP file. The results of including static and dynamic resources are quite different. If the resource is static, its content is inserted into the calling JSP file. If the resource is dynamic, the request is sent to the included resource, the included page is executed, and then the result is included in the response from the calling JSP page. The syntax for the jsp:include element is as follows:
<jsp:include page="includedPage" />
Think of the include directive as a header file of languages like C/C++. When using the include directive, the combined contents of the original JSP page and all its included resources are translated into the same implementation servlet i.e. the contents of the included resource is copy pasted before translation to a servlet. The important thing here is that all this happens during translation time and only static content is supported.
On the other hand, the include action <jsp:include> is almost similar to the include directive except for a few subtle differences. The include action is executed at request time as opposed to translation time. Thus instead of the content of the include file being included in the calling JSP, the output of the JSP is included or passed to the JSPWriter of the calling page. This allows us to include both static and dynamic content into the JSP page. Using the jsp action also allows you to explicitly pass parameters to the included page.
Think of the include directive as a header file of languages like C/C++. When using the include directive, the combined contents of the original JSP page and all its included resources are translated into the same implementation servlet i.e. the contents of the included resource is copy pasted before translation to a servlet. The important thing here is that all this happens during translation time and only static content is supported.
On the other hand, the include action <jsp:include> is almost similar to the include directive except for a few subtle differences. The include action is executed at request time as opposed to translation time. Thus instead of the content of the include file being included in the calling JSP, the output of the JSP is included or passed to the JSPWriter of the calling page. This allows us to include both static and dynamic content into the JSP page. Using the jsp action also allows you to explicitly pass parameters to the included page.
