Syntax:<\/strong><\/p>\n<%@ directive name [attribute=\u201dvalue\u201dattribute=\u201dvalue\u201d\u2026..]%>\r\n<\/pre>\nNote:<\/strong><\/em> They <%@……%> should lie in the same physical file.<\/p>\nClassification of Directives under 3 categories is as follows:<\/strong><\/p>\n2.1 Page Directive<\/h4>\n
It defines the attributes for the JSP page as a whole.
\nSyntax:<\/strong><\/p>\n<%@ page[attribute=\u201dvalue\u201dattribute=\u201dvalue\u201d]%>\r\n<\/pre>\nThe attributes of the page directive are:<\/p>\n
\n- language<\/li>\n
- extends<\/li>\n
- import<\/li>\n
- session<\/li>\n
- buffer<\/li>\n
- autoflush<\/li>\n
- isThreadsafe<\/li>\n
- info<\/li>\n
- isErrorpage<\/li>\n
- errorpage<\/li>\n
- contentType<\/li>\n<\/ul>\n
For Example:<\/strong><\/p>\n<%@ page language=\u201djava\u201d contentType=\u201dtext\/.html\u201d>\r\n<\/pre>\nExplanation:<\/strong>
\nThis code implies that coding of the page has been done in Java where the contentType of output is text or an HTML response. We won\u2019t get an output here as directives are an offset to the JSP code only.<\/p>\n2.2 Include Directive<\/h4>\n
It works similarly to the #include of the C preprocessor directory. It\u2019s work is to merge the contents of another file into .jsp input stream at the translation phase. Syntax:<\/strong><\/p>\n<%@ include file=\u201dfilename\u201d%>\r\n<\/pre>\nFor Example:<\/strong><\/p>\n<%@ include file=\u201dheader.html\u201d>\r\n<%@ include file=\u201dsortmethod\u201d>\r\n<\/pre>\nExplanation:<\/strong> The \u201cfilename\u201d can be the absolute name or the relative path name as shown in the example. There is no body coding here, only the use of include tag is shown so output is not there.<\/p>\n2.3 Taglib Directive<\/h4>\n
With the use of tag library this directive makes the custom tags available in the current page. Syntax can be shown as:<\/strong><\/p>\n<%@ taglib uri=\u201dtaglib URI\u201dprefix=\u201dtagPrefix\u201d%>\r\n<\/pre>\nThe attributes of this directive are:<\/p>\n
\n- tagLibrary URI<\/li>\n
- tagPrefix<\/li>\n<\/ul>\n
**The JSP directives section contains a detailed description of this topic.<\/p>\n
3. Actions<\/h3>\n
Actions also known as standard actions unlike others are written in XML. These are also known as high level JSP elements. They create, modify or use other objects. Syntax:<\/strong><\/p>\n<tagname attr=\u201dvalue\u201d:\u2026.>\u2026.body\u2026\u2026.<\/tagname>\r\n<\/pre>\nProper nesting is important here. For e.g. <A><B>\u2026\u2026\u2026.<\/B><\/A> is right whereas <A><B>\u2026\u2026\u2026<\/A><\/B> is wrong.
\nImportant tags in actions are namely:<\/p>\n
\n- <jsp:usebean><\/li>\n
- <jsp:setProperty><\/li>\n
- <jsp:getProperty><\/li>\n
- <jsp:include><\/li>\n
- <jsp:forward><\/li>\n
- <jsp:param><\/li>\n
- <jsp:plugin><\/li>\n<\/ul>\n
**The article JSP Actions contains a detailed description of this topic.
\nHaving discussed the three essential elements of the JSP page, let’s discuss the periphery elements of a JSP page.<\/p>\n
JSP Comments<\/h2>\n
Comments contain statements and texts but are ignored. They simply describe the code so that the usability and understanding increases.
\nThere are two types of comments in a JSP page. They are:
\nFirstly, JSPcomments that are written in the JSP code. JSP container ignores these comments. Syntax:<\/strong><\/p>\n<%----Hidden JSP comment----%>\r\n<\/pre>\nSecondly the HTML comments that are written in the XML or HTML code. Browser ignores these comments. Syntax:<\/strong><\/p>\n<!----included in generated HTML----!>\r\n<\/pre>\nExample:<\/strong><\/p>\n<html>\r\n<head><title>Comments<\/title>\r\n<!---This is an HTML comment--->\r\n<h6>--DataFlair--<\/h6>\r\n<\/head>\r\n<body>\r\n \r\n<%---This is a JSP comment---%>\r\n<% int a=1;\r\n \tint b=2;\r\n \tout.println(\"The addition of a and b is:\" + a+b);\r\n%>\r\n<\/body>\r\n<\/html>\r\n<\/pre>\nExplanation:<\/strong> In the generated output you can compare, the code and result. JSP and HTML comments get ignored by the JSP container and browser respectively.<\/p>\nOutput:<\/strong><\/p>\n
![\"JSP](\"https:\/\/data-flair.training\/blogs\/wp-content\/uploads\/sites\/2\/2020\/08\/JSP-Syntax-Semantics.jpg\")
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