URL Rewriting in Servlet – Java Example
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import java.io.IOException; import java.io.PrintWriter; import java.io.UnsupportedEncodingException; import java.net.URLEncoder; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ShoppingCartViewerRewrite extends HttpServlet { public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { res.setContentType("text/html"); PrintWriter out = res.getWriter(); out.println("<HEAD><TITLE>Current Shopping Cart Items</TITLE></HEAD>"); out.println("<BODY>"); // Get the current session ID, or generate one if necessary String sessionid = req.getPathInfo(); if (sessionid == null) { sessionid = generateSessionId(); } // Cart items are associated with the session ID String[] items = getItemsFromCart(sessionid); // Print the current cart items. out.println("You currently have the following items in your cart:<BR>"); if (items == null) { out.println("<B>None</B>"); } else { out.println("<UL>"); for (int i = 0; i < items.length; i++) { out.println("<LI>" + items[i]); } out.println("</UL>"); } // Ask if the user wants to add more items or check out. // Include the session ID in the action URL. out.println("<FORM ACTION=\"/servlet/ShoppingCart/" + sessionid + "\" METHOD=POST>"); out.println("Would you like to<BR>"); out.println("<INPUT TYPE=SUBMIT VALUE=\" Add More Items \">"); out.println("<INPUT TYPE=SUBMIT VALUE=\" Check Out \">"); out.println("</FORM>"); // Offer a help page. Include the session ID in the URL. out.println("For help, click <A HREF=\"/servlet/Help/" + sessionid + "?topic=ShoppingCartViewerRewrite\">here</A>"); out.println("</BODY></HTML>"); } private static String generateSessionId() throws UnsupportedEncodingException { String uid = new java.rmi.server.UID().toString(); // guaranteed unique return URLEncoder.encode(uid, "UTF-8"); // encode any special chars } private static String[] getItemsFromCart(String sessionid) { return new String[] { "a", "b" }; } } |