Recommended
More Related Content
What's hot
What's hot (14)
Viewers also liked
Viewers also liked (20)
Similar to 02 up close with servlets
Similar to 02 up close with servlets (20)
More from dhrubo kayal
02 up close with servlets
- 1. 02-Up Close with Servlets DhrubojyotiKayal
- 2. Servlet responses Request Response Sequence Servlet URLs Servlet life cycle Agenda
- 3. Exercise
- 4. Servlet with simple text response public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out = response.getWriter(); out.println("Hello World"); } Servlet Responses
- 5. Servlet with simple text response public void doGet(HttpServletRequestrequest,HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println ("<!DOCTYPE html>" + "<html>" + "<head><title>A Test Servlet</title></head>" + "<body bgcolor=quot;#fdf5e6quot;>" + "<h1>Test</h1>" + "<p>Simple servlet for testing.</p>" + "</body></html>"); } Other forms – XML, Excel, Word, PDF …. Servlet Responses
- 7. Java code com.empweb.web – package public class SimpleServlet extends HttpServlet web.xml register <servlet> <servlet-name>SimpleServlet</servlet-name> <servlet-class>com.empweb.web.SimpleServlet</servlet-class> </servlet> Map url <servlet-mapping> <servlet-name>SimpleServlet</servlet-name> <url-pattern>/simpleservlet</url-pattern> </servlet-mapping> Final URL – http://domain/context/servlet-name Servlet URLs
- 8. init () Executed once when the servlet is first loaded. Not called for each request. service () Called in a new thread by server for each request. Dispatches to doGet, doPost, etc. Do not override this method! doGet () / doPost () / doXXX() Handles GET, POST, etc. requests. Override these to provide desired behavior. destroy() Called when server deletes servlet instance. Not called after each request. Servlet Lifecycle
- 10. <servlet> <servlet-name>MyServletName</servlet-name> <servlet-class>com.mycompany.MyServlet</servlet-class> <init-param> <param-name> param1 </param-name> <param-value> value1 </param-value> </init-param> <init-param> <param-name> param2 </param-name> <param-value> value2 </param-value> </init-param> ... </servlet> Servlet Initialization
- 11. @Override public void init() throws ServletException { String value = getServletConfig().getInitParameter("param1"); System.out.println(value); } Initial Parameter and Values
- 12. Create servlet instances before a request comes in Order of creating servlet instances Load on Startup
- 13. Q&A