9 Servlet JSP

ServletServletCGIServletHttpServlet HttpServletRequestHttpServletRepsonseServletContext RequestDispatcherServletConfigServlet

ServletServletjavaWebCGIServletAppletWeb

ServletHTTPServletServletJVMServletHTTPServlet

ServletBrowser(Client)1. ClientServer5. ServerClientWeb Server2. ServerServlet3. ServletServletService4. ServletServer

ServletCGI WebServletCGI Java Servlet APIWebServletServletJavaServletWebServlet ServletWebServletServletCGIServletCGI

ServletServlet ServletHTMLHTTPCOOKIEServletCGIServletServlet AppletJavaServletServlet

ServletServlet ServletServletServletServletServlet API ServletHTTPFTPHttpServlet

Servlet ServletServletWebJava Servlet APIServletWebServletServletWebServletWeb Container

Servlet WebServletServletWebServletServletServletServletServletWebServlet

Servlet

Java Servlet APIServletAPISerlvet APIJavaWebWeb ServletWebWebAPIAPI javax.servlet javax.servlet.http

Java Servlet APIjavax.servlet.ServletJava Servlet ServletService

Java Servlet APIGenericServletjavax.servlet.ServletServletWebHttpServletjavax.servlet.http.HttpServletGenericServlet

ServletServletServletWebServlet javax.servlet.Servlet init() service() destroy()

Servlet

API(1/3)1Servletservlet Servletinit()init ServletConfigService

API(2/3)2Servlet HttpServletRequest HttpServletResponseHTMLHttpServletResponse service()doGet()doPost()

API(3/3)3Servlet WebSERVLETdestroy()

Servletpachage simple.servlet;import java.io.*;import javax.servlet.*;import javax.servlet.http.*;public class FirstSimpleServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletExceptionIOException{ response.setContentType("text/html"); PrintWriter out=response.getWriter(); out.println("First servlet "); out.println("This is your first servlet. "); out.println(""); }}

ServletJava

importJavapachage simple.servlet;import java.io.*;import javax.servlet.*;import javax.servlet.http.*; java.iojava IOjavax.servletjavax.servlet.httpServlet API

Servicepublic class FirstSimpleServlet extends HttpServlet{ protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException.IOException{ response.setContentType("text/html"); PrintWriter out=response.getWriter(); out.println("First servlet "); out.println("This is your first servlet. "); out.println(""); }}

HttpServletJavax.servlet.http.HttpServletHTTPHTTP doGet()GET(URL) doPost()POST(HTML)service()doGet()doPost()init()destroy()

RequestsResponsesservice()doGet()doPost() HttpServletRequest HttpServletResponseservlet

HttpServletRequestHTTP servletURL HttpServletRequest

HTTPHTTPPOST /Music/SearchServlet HTTP/1.0Referer:http://www.music.ibm.com/musicSearch.htmlConnection:Keep-AliveUser-Agent:Mozilla/4.72[en](WinNT 5.0; U)Host:localhost:8080Accept:image/gif,image/x-xbitmap,image/jpeg,*/*Accept-Language:enAccept-Charset:iso-8859-1,*,utf-8Content-length:50song_title=Hello&song_artist=Jones&limit_number=20

HttpServletRequestHTTPgetHeader("headername") getHeader("Accept-Language")Content-typeContent-length getContentType() getContentLengthCookie getCookies()getMethod()

private void processRequest(HttpServletRequest request, HttpServletResponse response) { ...... String method=request.getMethod(); if(method.equals("GET")) { // } String lang=request.getHeader("Accept- Language"); // ...... }

HttpServletRequest URL POST getParameterNames() getParameterValues(String name) getParameter(String name)

Please fill out this form with the song's name.

Song Name: Artist Name: Thank you!

public class SearchServlet extends HttpServlet{ public void doPost(HttpServletRequest req, HttpServletResonse res) throws ServletException,IOException{ ... Enumeration enum=req.getParameterName(); while(enum.hasMoreElements()){ String name=(String)enum.netElement(); String value=req.getParameter(name); // } }}String title=req.getParameter("song_title");

HttpServletResponseHttpServletResponseServletHttpServletResponsecontent typecontent Header(cookies,caching)URL

HttpServletRepsonseHTTP

setContentType(String type)getWriter() PrintWritergetOutputStream() ServletOutputStreamHTTP/1.1 200 OKContent-Type;text/plainHello World

HTTP 1.1HTTP 1.11**2** 200 OK3** 301 Moved Permanently4** 404 Not Found5** 503 Service Unavailable

HttpServletResponseHttpServletResponse.setStatus() HTTP 1.1SC 404SC_NOT_FOUNDPrintWriterresponse.setStatus()

public class MyServlet extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException,IOException{ res.setStatus(HttpServletResponse.SC_OK); res.setContentType("text/html"); PrintWriter out=res.getWriter(); out.println(" Today is " +(new Date())); out.println(""); } }

Servletpackage simple.servletimport javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.ServletException;import javax.io.IOException;import javax.io.PrintWriter;public class AnotherSimpleServlet extends HttpServlet{ public void doGet(HttpServletRequest request, HttpServletResponse response) throws SERVLETException,IOException{ String browser=request.getHeader("User-Agent"); response.setStatus(HttpServletResponse.SC_OK); response.setContentType("text/html"); PrintWriter out=response.getWriter(); out.println("First servlet"); out.println("Browse details:"+browser+""); } }

Web ContainersServlet Contextjavax.servlet.ServletContext Servlet

Request Dispatcherjava.servlet.RequestDispatcherforward Webinclude include

forwardinclude

getRequestDispatcher()getServletContext() getRequestDispatcher("/pages/ showBalance.jsp").forward(req,res);getServletContext() getRequestDispatcher("/pages/navigation.html").include(req,res);

forward()private void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOExcption{ ... if(errorFound){ String errorPage="/ErrorFound.html"; getServletContext(). getRequestDispatcher(errorPage). forward(request,response); return; } }

ServletJSPServletContext getServletContext().setAttribute ("objectName",anObject); getServletContext().setAttribute ("objectName");HttpServletRequest request.setAttribute ("objectName",anObject) request.getAttribute("objectName");

//Servlet "A"private void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException,IOException{ Customer cust; ... req.setAttribute("CUSTOMER",cust); String nextServlet="/Internal/ServletB"; getServletContext().getRequestDispatcher(nextServlet). forward(req,res); return; }

//Servlet "B"private void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException,IOException{ Customer aCust=(Customer)req.getAttribute("CUSTOMER"); ... }

ServletConfigjavax.servlet.ServletConfig ContainerServlet ServletConfigServlet getServletConfig()public String getInitParameter(String name)public Enumeration getInitParameterNames()

Servlet

Servlet

ServletServletCGIServletHttpServlet HttpServletRequestHttpServletResponseServletContext RequestDispatcherServletConfigServlet

ServletEclipse

HttpServletInfotest

Info

web.xml/WEB-INF

Tomcathttp://localhost:8080/chapter03/Info

WebServlet1SerlvetServletServletWeb.javax.servletServletServletHTTPFTPjavax.serlvet.httpHTTP Httpservletjavax.servlet.ServletServletJava ServletServletWeb ContainerinitservicedestroyServlet ServletSERVLETWeb Containerservlet,ContainerServletServletinitSERVLETServletServletSERVLETWeb ContainerServletWeb ContainerServletservice WebSERVLETdestroyServletServletSERVLET APIServletServletServletServletServletServletServletServletinitinitServletServletJDBCServletinitServletConfigServletConfigServletServletConfigServletServletConfigServiceServletJava Servlet APIServletRequestSERVLETResponseHttpServletHttpServletRequestHttpServletResponseHttpServletRequestHttpSerlvetResponseHTMLHttpServletResponseSerlvetServletServletservicedoGetdoPostHttpServletResponseHttpServletRequest WebSERVLETdestroyServicefirstsimpleservletHttpServletHttpServletserviceserviceHttpServletRequestHttpServletResponse HTMLsetContentTypetext/htmloutPrintWriteroutprintlnHTMLHTMLHTMLGetPost

ServletHTTFTPJavax.serlvet.httpHttpServletHTTPGetPostHttpServletHTTPdoGetdoPostHTMLHTTP GetRULdoGet GetURLHTMLPOSTdoPostPOSTdoPost servicedoGetdoPost servicedogetdopostHttpServletRequest,HttpServletResponseRequestHttpServletRequestResponseHTMLHTMLHttpServletResponseHTMLHTTPURLServletServletHttpServletRequestHTTPHTTPHTTPGetPostIEmozicServletURLCOOKIEURLHttpServletRequest RequestHTTPHTTPPOSTRULServletHTTP1.0refererURLURLConnectionServletkeep-alive1.11.1ServletUser-AgentMozillaServletHostURLAcceptMIMEAccept-LanguageHTMLAccept-CharsetContent-lenthURL HTTPServletHTTPHttpServletRequestgetHeaderheaderAccept-LanguagegetHeaderContent-typeContent-lenthgetContentTypegetContentLenthgetCookiesCookieCookiegetMethodGETPost processRequestdoGetdoPostdoGetdoPostrequestgetMethodStingIfrequest.getHEADERAccept-Lanuage HTTPURLparastringPOSTURLPOSTHttpServletRequestgetParameterNamesgetParameterValuesnamegetParameter(String name)HTMLMETHODPostPostWebActionServlet URLSUBMMITSearchServletServletsong_titlesong_artistHTTPServletHttpServletRequestSearchServletServletRequestgetParameterNamessong_title,song_artistenumhasMoreElementsgetParametersong_titlesong_title HttpSerlvetResponseServletHttpServletResponseHTMLHttpServletResponseHTTPcontenttypeContent HeaderCookiesHTTPURLHttpServletResponseServletwebweb200OKContent-TypeMIMEHttpServletResponsesetContentTypeContentTypegetWriterPrintWriterPrintWriterPrintWriterHTMLXMlgetOutputStreamServletOutputStreamHTTP1.112200 OKGETPOST3301 Moved PernanentlyURLLocationURL4401 unauthorright404 Not Found5503 Service UnavailableServlet503 ServletHttpServletResponsesetStatussetStatusHttpServletResponseHTTP1.1SCStatus Code404Not FoundHttpServletResponseSC_NOT_FOUNDPrintWriterresponse.setStatusservletHTMLdoGetHttpServletResponseSetstatusSetContentTypeHTTPHTMLPrintWriterout,HTMLoutSerlvetdoGetHTMLSerlvetAnotherSimpleSerlvetjavasimple.servletimportjavaAntherSimpleServletHttpServletdoGetHttpServletRequestgetHeaderUser-AgentContentTypePrintWriteroutHTMLServlet ContextWebServlet Contextjavax.servlet.ServletContextservlet ContextWebWebWebwww.hotel.ibm.comWebWeb ContainerHRAppsPersonnelServletHireRetireServletRoomsServletLog inDisplayRoomsServlet ContextURLServletWeb ContainerWebWebServletJSPServletforwardincludeforwardincludejava.servlet.ResponseDispatcherforwardWebforwardJavaBeanincludeforwardincludeincludeforwardincludeforwardServlet AServlet BincludeServlet BSERVLET ArequestDispatcherServletContextgetRequestDispatcherDispatcherforwardinclude forwardprocessRequsetErrorFound.htmlgetServletContextServletContextgetRequestDispatcherRequestDispatcherforwardErrorFound.htmlServletJSPWebServletContextServletServletContextgetServletContext.setAttributeforwardincludeHttpServletRequestgetAttributesetAttributeSerlvetServlet AServlet BServlet ARequestDispatcherforwardServlet BSERVLET ACUSTOMERcustsetAttributeHttpServletRequestServlet B,HttpServletRequestHttpServletResponseSerlvet BServlet BgetAtrributecustServletConfigServletConfigjavax.servlet.ServletConfigContainerServletServletConfigServletServletConfigServletServletConfiggetServletConfigServletConfigServletConfiggetInitParametergetInitParameterNamesServletServletClient1Client2Servlet ASerlvet A Thread1Thread2ServletThread1Thread2SerlvetConfigServletContextThread1Thread2SerlvetContextServletRequestServletResponseServletThread1Thread2ServletRequestServletResponseClient1Client2WebServletservletASerlvetBWebThread1Thread2servletContextServletSerlvetASerlvetBServletConfigThread1Thread2ServletConfigServletRequestServletResponseServletThread1Thread2ServletRequestServletResponse