JSP Directives:
Introduction :
A JSP directive gives special information about the page to JSP Engine at page translation time.JSP directives serve as a message from a JSP page to the JSP container and control the processing of the entire page.
Directives are always enclosed within <%@ ... %> tag.
There are three types of directive: page,include and taglib .
Page directive :
The page directive allows to apply different attributes that is to be added to a JSP. These attributes gives special processing information to the JSP engine which allows the way of processing JSP pages.
Introduction :
A JSP directive gives special information about the page to JSP Engine at page translation time.JSP directives serve as a message from a JSP page to the JSP container and control the processing of the entire page.
Directives are always enclosed within <%@ ... %> tag.
There are three types of directive: page,include and taglib .
Page directive :
The page directive allows to apply different attributes that is to be added to a JSP. These attributes gives special processing information to the JSP engine which allows the way of processing JSP pages.
Following are the various page directives that are used in JSP
- language
- extends
- import
- session
- buffer
- autoFlush
- isThreadSafe
- errorPage
- info
- isErrorPage
- contentType
| Attribute | Description | Syntax | Example |
|---|---|---|---|
| language | This attribute is used to specify the language whose statements are allow inside the JSP.Currently the only valid value for this attribute is java. | language="java" | <%@ page language= "java" %> |
| Import | Import attribute is used to specify the package which you want to import for the translated servlet class. | import=" package.class " | <%@ page import= "java.util.*, java.io.*" %> |
| Extends | Indicates the superclass of servlet when jsp translated in servlet. | extends=" package.class " | <%@ page extends= "com.Connect"%> |
| Session | Possible values for this attributes are true/false default value is true. If you specify the session value as false then session implicit object will be disabled. | session=" true |false" | <%@ page session= "true" %> |
| Buffer | specifies the buffer size for out and default is 8kb. | buffer=" size kb|none" | <%@ page buffer= "8kb" %> |
| isThreadSafe | True indicates multi threading and false indicates that the servlet should implement SingleThreadModel | isThreadSafe=" true | false" | <%@ page isThreadSafe="true"%> |
| autoFlush | true indicates that the buffer should be flushed when it is full and false indicates that an exception should be thrown when the buffer overflows. | autoflush =" true |false" | <%@ page autoFlush= "true" %> |
| Info | This defines a string that can be retrieved via the getServletInfo method. | info=" message " | <%@ page info="This is a simple jsp file "%> |
| pageEncoding | This defines data type of page encoding. | pageEncoding="ISO-8859-1" | <%@ page pageEncoding="ISO-8859-1"%> |
| contentType | This specifies the MIME type of the output. | contentType=" MIME-Type " | <%@ page contentType="text/html; charset=ISO-8859-1"%> |
| isELIgnored | This defines ENUM data type. | isELIgnored=" true| false " | <%@ page isELIgnored="false"%> |
| isErrorPage | This indicates whether or not the current page can act as the error page. | isErrorPage="true| false " | <%@ page isErrorPage="false"%> |
| errorPage | Define a URL to another JSP that is invoked if an unchecked runtime exception is thrown. | errorPage=" url " | <%@ page errorPage="error.jsp"%> |
taglib directive :
it is used to use the custom tags developed by you in JSP & also used to use JSTL tags inside the JSP.
Syntax:<%@taglib uri="some uri" prefix="some prefix"%>
Include Directive :
It is used to include one Jsp or Html to another JSP.
Syntax:<%@ include file="abc" %>
Example:
<% @ include file="/header.jsp"%>
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