Intro to servlets intro Servlets ppt typical web

Intro to servlets intro. Servlets. ppt

typical web page – source <html> <head> <meta http-equiv=Content-Type content="text/html”> <meta http-equiv=Content-Type content="text/html; charset=windows-1252"> <title>Hello</title> </head> <body> Hello </body> </html> intro. Servlets. ppt

HTTP client-server model HTTP request web client (browser) HTTP response intro. Servlets. ppt web server (Apache)

Hyper. Text Transport Protocol (HTTP) client-server scenario • a web server is a program • plays the role of “server” • runs all the time but does nothing much • listens on some TCP port until called • if called, formulates an answer and sends it to the client • as a string (or stream or file) • a web browser is a program • plays the role of “client” • runs if a user starts it • if the user instructs clicks something: 1. sends a URL to a web server 2. waits to receive a plain text file from web server 3. formats (displays) the contents of the received file (string or stream) 4. the three steps above may be repeated if the page contains images • by file, string or stream, I mean: • a one-dimensional array of printable characters intro. Servlets. ppt

servlet URL General form: http: //server. Name: port/context. Name port Example: http: //harborsparrow. com: 80/hello context Typical: http: //harborsparrow. com/hello context intro. Servlets. ppt

Java web application web server (Apache) servlet container (Tomcat) HTTP request web client (browser) 1 2 5 HTTP response 3 4 1 = Servlet. Context object 2 = Http. Servlet. Request object 3 = Http. Servlet. Response object 4 = Http. Servlet object 5 = web. xml file intro. Servlets. ppt

Java web application that calls across the network to something else web server (Apache) servlet container (Tomcat) HTTP request web client (browser) 1 2 5 HTTP response 3 4 1 = Servlet. Context object 2 = Http. Servlet. Request object 3 = Http. Servlet. Response object 4 = Http. Servlet object 5 = web. xml file remote computer (database or other) intro. Servlets. ppt

Hello servlet intro. Servlets. ppt

code public class Hello extends Http. Servlet { public void do. Post(Http. Servlet. Request request, Http. Servlet. Response response) throws IOException, Servlet. Exception { response. set. Content. Type("text/html"); Print. Writer out = response. get. Writer(); out. println("<html>"); out. println("<head>"); out. println("<title>"); out. println("Hello"); out. println("</title>"); out. println("</head>"); out. println("<body>"); out. println("Hello"); out. println("</body>"); out. println("</html>"); } /* end do. Post */ public void do. Get(Http. Servlet. Request request, Http. Servlet. Response response) throws IOException, Servlet. Exception { do. Post(request, response); } /* end do. Get */ } // end class intro. Servlets. ppt

web. xml (deployment descriptor) for Tomcat <? xml version="1. 0" encoding="ISO-8859 -1"? > <web-app xmlns="http: //java. sun. com/xml/ns/j 2 ee" xmlns: xsi="http: //www. w 3. org/2001/XMLSchema-instance" xsi: schema. Location="http: //java. sun. com/xml/ns/j 2 ee/web-app_2_4. xsd" version="2. 4"> <servlet-name>Hello</servlet-name> <servlet-class>Hello</servlet-class> </servlet> <servlet-mapping> <servlet-name>Hello</servlet-name> <url-pattern>/servlet/Hello</url-pattern> </servlet-mapping> </web-app> intro. Servlets. ppt

directory structure for Tomcat intro. Servlets. ppt

the end of this Power. Point file Hooray! intro. Servlets. ppt