{"id":1959,"date":"2011-04-13T15:23:55","date_gmt":"2011-04-13T09:53:55","guid":{"rendered":"http:\/\/JitendraZaa.com\/blog\/?p=1959"},"modified":"2011-04-13T15:23:55","modified_gmt":"2011-04-13T09:53:55","slug":"create-servlet-using-annotation","status":"publish","type":"post","link":"https:\/\/www.jitendrazaa.com\/blog\/java\/servlet\/create-servlet-using-annotation\/","title":{"rendered":"Create Servlet using Annotation – Servlet 3.0"},"content":{"rendered":"

Before reading this article, i will suggest readers to go through the version table of J2EE.<\/a><\/p>\n

One of the most appraised feature of Servlet 3.0 is the support of the annotations to create the Servlet. Before\u00a0 this the Deployment Descriptor (web.xml) was used to create the servlet mapping , defining init parameters etc. All the settings can be now achieved without any entry in web.xml.<\/p>\n

Prerequisite:<\/strong><\/span><\/p>\n

    \n
  1. JDK 5.0 and above.<\/li>\n
  2. Tomcat 7<\/li>\n
  3. Eclipse 3.6 – Helios (as of now, it only supports Tomcat 7)<\/li>\n<\/ol>\n

    We will start with creating the Servlet class :<\/p>\n

    \npackage com.g2.servlet;\n\nimport java.io.IOException;\nimport java.io.PrintWriter;\n\nimport javax.servlet.ServletException;\nimport javax.servlet.annotation.WebInitParam;\nimport javax.servlet.annotation.WebServlet;\nimport javax.servlet.http.HttpServlet;\nimport javax.servlet.http.HttpServletRequest;\nimport javax.servlet.http.HttpServletResponse;\n\n@WebServlet(\n\t\tname="TestServlet",\n\t\turlPatterns={"\/test","\/testServlet"},\n\t\tinitParams={\n\t\t\t\t@WebInitParam(name="db",value="Oracle"),\n\t\t\t\t@WebInitParam(name="jdk",value="6"),\n\t\t\t\t@WebInitParam(name="tomcat",value="7")\n\t\t\t\t}\n\t\t\t)\npublic class ServletUsingAnnotation extends HttpServlet{\n\n\t@Override\n\tprotected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {\n\t\tPrintWriter pw = res.getWriter();\n\n\t\tres.setContentType("text\/html");\n\t\tpw.write("Running Servlet using Annotation..");\n\t\tpw.write("<br \/>");\n\t\tpw.write("-- Init parameters --");\n\t\tpw.write("<br \/>");\n\t\tpw.write("db : "+this.getInitParameter("db"));\n\t\tpw.write("<br \/>");\n\t\tpw.write("jdk : "+this.getInitParameter("jdk"));\n\t\tpw.write("<br \/>");\n\t\tpw.write("tomcat : "+this.getInitParameter("tomcat"));\n\t}\n}\n<\/pre>\n
    As you can see in above code, we have used annotation “@WebServlet<\/strong>” to declare this class as servlet. to pass the init parameter to servlet, we have used “@WebInitParam<\/strong>“. Before Servlet 2.5 we were not able to specify multiple url for the same servlet. As you can see in above code, we have given two URLs for the same servlet.<\/p>\n
    Create “index.jsp” page :<\/p>\n
    \n<%@ page language="java" contentType="text\/html; charset=ISO-8859-1"\n    pageEncoding="ISO-8859-1"%>\n<html>\n<head>\n<meta http-equiv="Content-Type" content="text\/html; charset=ISO-8859-1">\n<title>Creating servlet using Annotation<\/title>\n<\/head>\n<body>\n<a href="..\/test">Servlet using Annotation<\/a>\n<\/body>\n<\/html>\n<\/pre>\n
    After clicking on hyperlink on page “index.jsp” Servlet will open with following output.<\/p>\n
    Running Servlet using Annotation..
    \n— Init parameters —
    \ndb : Oracle
    \njdk : 6
    \ntomcat : 7<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"
    Create the Servlet without any deployment descriptor. Using Annotations<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"jz_research_post":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[11],"tags":[125],"class_list":["post-1959","post","type-post","status-publish","format-standard","hentry","category-servlet","tag-j2ee"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":1482,"url":"https:\/\/www.jitendrazaa.com\/blog\/java\/servlet\/how-container-handles-the-servlet-request\/","url_meta":{"origin":1959,"position":0},"title":"How container handles the Servlet 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