Life Cycle of JSP “BodyTag” interface<\/a>.<\/p>\n This article is about creating custom Tag in JSP using “Tag” interface. Types of Tag:<\/strong> Tag with body:<\/p>\n As ther are two types of tag, there are two way of creating them in JSP:<\/p>\n In this article, I will use the interface approach<\/strong>, so that the beginners can get broader idea about how Tag library actually implemented.<\/p>\n <\/strong>Create a class which implements interface Tag.<\/p>\n In above class, you can see that I have created two objects of Tag<\/strong> and PageContext<\/strong>. getParent() and setParent() method uses the object of Tag to specify that who is the parent of that custom Tag. setPageContext() is used to set the PageContext for out custom Tag. Step 2 : create Tag Library Descriptor (TLD) File<\/strong><\/p>\n Now create xml file named “CustomTags.tld”\u009d in folder “WEB-INF\/tlds<\/strong>“\u009d and below code lines:<\/p>\n We can also make Tag Handler class and tld file\u00a0accessible\u00a0by creating a jar and placing in lib folder.<\/strong><\/span><\/p>\n tlibversion <\/strong>\u2013 Your tag library version Now create “index.jsp”\u009d with following lines of code:<\/p>\n
\nCreating custom tag in JSP has its unique advantages. This is same as Custom controls of the ASP.Net.
\nBy creating the Custom tag, we can resuse that tag every where in our application. Best example of custom tags are the Struts.<\/p>\n
\nTag without body:<\/p>\n\n<ct:showTime displayTime=\"\u009dfalse\"\u009d \/>\n<\/pre>\n
\n<ct:showTime displayTime=\"\u009dfalse\"\u009d >\nCurrent Time is :\n<\/ct:showTime>\n<\/pre>\n
\n
\n
\n
![\"How](\"https:\/\/i0.wp.com\/jitendrazaa.com\/blog\/wp-content\/uploads\/2011\/03\/How-to-Create-Custom-Tag-in-JSP.jpg?resize=470%2C609&ssl=1\" "\\"How")
<\/a>
\nStep 1: Write Tag Handler Class<\/strong><\/p>\n\npackage com.G2.CustomTag;\n\nimport java.io.IOException;\nimport java.text.SimpleDateFormat;\nimport java.util.Date;\n\nimport javax.servlet.jsp.JspException;\nimport javax.servlet.jsp.JspWriter;\nimport javax.servlet.jsp.PageContext;\nimport javax.servlet.jsp.tagext.Tag;\n\npublic class DisplayDate implements Tag {\n\n\tprivate PageContext pc = null;\n\tprivate Tag parent = null;\n\tprivate boolean displayDate;\n\n\tpublic boolean isDisplayDate() {\n\t\treturn displayDate;\n\t}\n\n\tpublic void setDisplayDate(boolean displayDate) {\n\t\tthis.displayDate = displayDate;\n\t}\n\n\t@Override\n\tpublic int doEndTag() throws JspException {\n\t\treturn EVAL_PAGE;\n\t}\n\n\t@Override\n\tpublic int doStartTag() throws JspException {\n\t\ttry {\n\t\t\tJspWriter out = pc.getOut();\n\t\t\tif (isDisplayDate()) {\n\t\t\t\tSimpleDateFormat frm = new SimpleDateFormat("dd-MMM-yyy EEEE");\n\t\t\t\tout.print(frm.format(new Date()));\n\t\t\t} else {\n\t\t\t\tout.print("Custom Tag is not configured to display Date");\n\t\t\t}\n\t\t} catch (IOException e) {\n\t\t\tthrow new JspException(e);\n\t\t}\n\t\treturn SKIP_BODY;\n\t}\n\n\t@Override\n\tpublic Tag getParent() {\n\n\t\treturn parent;\n\t}\n\n\t@Override\n\tpublic void release() {\n\t\tpc = null;\n\t\tparent = null;\n\t}\n\n\t@Override\n\tpublic void setPageContext(PageContext arg0) {\n\t\tpc = arg0;\n\t}\n\n\t@Override\n\tpublic void setParent(Tag arg0) {\n\t\tparent = arg0;\n\t}\n\n}\n<\/pre>\n
\nTag Attributes must have setters and getters, in above class displayDate is the attribute.
\ndoStartTag()<\/strong>, this is the method where we have to write our code. If the attributes value is true then it displays the date other wise displays the message.
\nrelease()<\/strong>, this method is responsible to clear all the resources used by this custom tag. To know more about the life cycle of custom tag using Tag interface, please read this article.<\/p>\n\n<?xml version="1.0" encoding="UTF-8"?>\n<!DOCTYPE taglib PUBLIC "-\/\/Sun Microsystems, Inc.\/\/DTD JSP Tag Library 1.1\/\/EN"\n"http:\/\/java.sun.com\/j2ee\/dtds\/web-jsptaglibrary_1_1.dtd">\n<taglib>\n\t<tlibversion>1.0.0<\/tlibversion>\n\t<jspversion>1.1<\/jspversion>\n\t<shortname>CustomTag<\/shortname>\n\t<uri>https:\/\/jitendrazaa.com\/blog<\/uri>\n\t<info>Custom tags<\/info>\n\t<tag>\n\t\t<name>ShowDate<\/name>\n\t\t<tagclass>com.G2.CustomTag.DisplayDate<\/tagclass>\n\t\t<bodycontent>empty<\/bodycontent>\n\t\t<info>Custom tag used to display the current date<\/info>\n\t\t<attribute>\n\t\t\t<name>displayDate<\/name>\n\t\t\t<required>true<\/required>\n\t\t<\/attribute>\n\t<\/tag>\n<\/taglib>\n\n<\/pre>\n
\njspversion <\/strong>\u2013 jsp version
\nshortname <\/strong>– Refers to the name of the JSP Custom Tag that your jsp code will be referring to
\nname <\/strong>\u2013 Refers to the name the Custom Tags
\ntagclass <\/strong>\u2013 Refersn to the class structure used for your JSP Tags
\nbodycontent <\/strong>\u2013 This is used in case we are using BodyTagSupport, in TagSupport we keep this empty.<\/p>\n\n<%@ page language="java" contentType="text\/html; charset=ISO-8859-1"\n\tpageEncoding="ISO-8859-1"%>\n<%@taglib uri="\/WEB-INF\/tlds\/CustomTags.tld" prefix="ct"%>\n<!DOCTYPE html PUBLIC "-\/\/W3C\/\/DTD HTML 4.01 Transitional\/\/EN" "http:\/\/www.w3.org\/TR\/html4\/loose.dtd">\n<html>\n<head>\n<meta http-equiv="Content-Type" content="text\/html; charset=ISO-8859-1">\n<title>Custom Tag<\/title>\n<\/head>\n<body>\n<h2>Custom tag to display date<\/h2>\n<ct:ShowDate displayDate="true" \/>\n<\/body>\n<\/html>\n<\/pre>\n
![\"output](\"https:\/\/i0.wp.com\/jitendrazaa.com\/blog\/wp-content\/uploads\/2011\/03\/output-of-the-custom-tag-created-using-Tag-interface.jpg?resize=280%2C151&ssl=1\" "\\"output")
<\/a>