Java ServletsPart I : Server and Servlet BasicsNetworkServer.javaSlide 4Slide 5Slide 6Slide 7Compile, Run and VisitEchoServer.javaSlide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19PostForm.htmlPostForm.html BrowserEchoServer Response Using POSTGetForm.htmlGetForm.html BrowserEchoServer Response Using GETA Form With CheckboxesCheckBoxes BrowserCheckBox ResponseRadioBoxes HTMLRadioBoxes BrowserEchoServer ResponseReading Form Data With Servlets Under TomcatSlide 33Slide 34Slide 35Slide 36Slide 37Organizing The Filesbuild.propertiesweb.xmlRunning Ant on build.xmlHandling CheckBoxesPizza ToppingsServlet ResponsePizzaData ServletSlide 46Slide 47Part II Session Tracking and Servlet CollaborationSession Tracking with ServletsTraditional Session TrackingUser AuthorizationShared ObjectsVisitTracker.javaSlide 54Slide 55Slide 56Slide 57Slide 58CookiesUsing CookiesSlide 61Slide 62Slide 63The New Session Tracking APIThe Session Tracking APISlide 66OCT 1Java Servlets Part I Server and Servlet Basics Part II Session Tracking and Servlet CollaborationOCT 2Part I : Server and Servlet Basics•NetworkServer.java and EchoServer.java•PostForm.html•GetForm.html•More HTML form examplesOCT 3NetworkServer.java// NetworkServer.java Adapted from "Core Servlets// and Java Server Pages" // by Marty Hallimport java.net.*;import java.io.*;public class NetworkServer { private int port; private int maxConnections; No Tomcat server.Just this code.OCT 4 protected void setPort(int port) { this.port = port; } public int getPort() { return port; } protected void setMaxConnections(int max) { maxConnections = max; } public int getMaxConnections() { return maxConnections; } public NetworkServer(int port, int maxConnections) { setPort(port); setMaxConnections(maxConnections); }OCT 5// Wait for a connections until maxConnections.// On each connection call handleConnection() passing// the socket. If maxConnections == 0 loop forever public void listen() { int i = 0; try { ServerSocket listener = new ServerSocket(port); Socket server ; while((i++ < maxConnections) || (maxConnections == 0)) { server = listener.accept(); // wait for connection handleConnection(server); } } catch (IOException ioe) { System.out.println("IOException : " + ioe); ioe.printStackTrace(); } }OCT 6// Open readers and writers to socket.// Display client's host name to console.// Read a line from the client and display it on the console.// Send "Generic network server" to the client.// Override this method.protected void handleConnection(Socket server) throws IOException { BufferedReader in = new BufferedReader( new InputStreamReader( server.getInputStream() )); PrintWriter out = new PrintWriter( server.getOutputStream(),true); Flush bufferon printlnInputStream forreading bytesReaders and Writersto work with charactersOCT 7System.out.println("Generic network server: got connection from "+ server.getInetAddress().getHostName() + "\n" + "with first line '" + in.readLine() + "'"); out.println("Generic network server"); server.close(); } public static void main(String args[]) { NetworkServer test = new NetworkServer(6502, 5); test.listen(); }} To server’sconsole.To client.OCT 8Compile, Run and VisitC:\McCarthy\www\46-928\examples\networking>java NetworkServerGeneric network server: got connection from localhostwith first line 'GET / HTTP/1.0'ClientServerOCT 9EchoServer.java/* From Core Servlets, Marty HallAn HTTP Request header example NotesGET /path/file.html HTTP/1.0 The whitespace is required.Accept: text/html Accept header fieldsAccept: audio/x tell the server MIME typesUser-agent: MacWeb (Multipurpose Internet Mail Extension) that are handled by the browser.Still no TomcatHTTP defines dozens of possible headers.Request terminated by two returnsOCT 10EchoServer.javaAn HTTP Response header example HTTP 1.0 200 OKServer: NCSA/1.4.2MIME-version: 1.0Content-type: text/htmlContent-length: 107<html>::</html>Blank lineMIME typeThe client must interpretthis MIME encoded data.Response codeOCT 11HTTP General form<method> <resource identifier> <HTTP Version> <crlf>[<Header> : <value>] <crlf> : : :[<Header> : <value>] <crlf> a blank line[entity body]The resource identifier field specifies the name of the targetresource; it's the URL stripped of the protocol and the serverdomain name. When using the GET method, this field will alsocontain a series of name=value pairs separated by ‘&’. When usinga POST method, the entity body contains these pairs.The HTTP version identifies the protocol used by the client.*/OCT 12// Adapted from Core Servlets and JavaServerPages// by Marty Hall, chapter 16import java.net.*;import java.io.*;import java.util.StringTokenizer;public class EchoServer extends NetworkServer { protected int maxRequestLines = 50; // Post data is brought in // as a single string. protected String serverName = "EchoServer"; public static void main(String a[]) { int port = 6502; new EchoServer(port,0); // loop forever }OCT 13public EchoServer(int port, int maxConnections) { super(port,maxConnections); // call base class constructor listen(); // call base class listen() } // listen calls handleConnection() // Overrides base class handleConection and is called by listen() public void handleConnection(Socket server) throws IOException { // Assign readers and writers to the socket BufferedReader in = new BufferedReader( new InputStreamReader( server.getInputStream() )); PrintWriter out = new
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