Jeg har lavet en web-app directory struktur og flyttet
tingene på plads.
Jeg har lavet en web.xml:
<?xml version="1.0"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "
http://java.sun.com/j2ee/dtds/web-app_2_2.dtd"><web-app>
<servlet>
<servlet-name>ChatDispatch</servlet-name>
<servlet-class>ChatDispatch</servlet-class>
</servlet>
<servlet>
<servlet-name>ChatServlet</servlet-name>
<servlet-class>ChatServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ChatDispatch</servlet-name>
<url-pattern>/ChatDispatch</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ChatServlet</servlet-name>
<url-pattern>/ChatServlet</url-pattern>
</servlet-mapping>
</web-app>
Jeg har rettet i ChatDispatcher så den bruger /chat i pathen:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ChatDispatch extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException {
res.setContentType("text/html");
if (!req.getParameterNames().hasMoreElements()) {
// There were no request parameters. Print a welcome page.
printWelcomePage(req, res);
}
else {
// There was at least one request parameter.
// Print a page containing the applet.
printAppletPage(req, res);
}
}
// The welcome page greets the reader and has a form where the user
// can choose an applet-servlet communication method.
private void printWelcomePage(HttpServletRequest req,
HttpServletResponse res)
throws IOException {
PrintWriter out = res.getWriter();
String me = req.getServletPath();
out.println("<HTML>");
out.println("<HEAD><TITLE>");
out.println("Welcome to an Absurdly Simple Chat");
out.println("</TITLE></HEAD>");
out.println();
out.println("<BODY>");
out.println("<H1>Welcome to an Absurdly Simple Chat</H1>");
out.println();
out.println("Would you like to communicate via:");
out.println("<UL>");
out.println(" <LI><A HREF=\"/chat" + me + "?method=http\">http</A>");
out.println(" <LI><A HREF=\"/chat" + me + "?method=socket\">socket</A>");
out.println(" <LI><A HREF=\"/chat" + me + "?method=rmi\">rmi</A>");
out.println("</UL>");
out.println("</BODY></HTML>");
}
// The applet page displays the chat applet.
private void printAppletPage(HttpServletRequest req,
HttpServletResponse res)
throws IOException {
PrintWriter out = res.getWriter();
out.println("<HTML>");
out.println("<HEAD><TITLE>An Absurdly Simple Chat</TITLE></HEAD>");
out.println("<BODY>");
out.println("<H1>An Absurdly Simple Chat</H1>");
String method = req.getParameter("method");
String user = req.getRemoteUser();
String applet = null;
if ("http".equals(method)) {
applet = "HttpChatApplet";
}
else if ("socket".equals(method)) {
applet = "SocketChatApplet";
}
else if ("rmi".equals(method)) {
applet = "RMIChatApplet";
}
else {
// No method given, or an invalid method given.
// Explain to the user what we expect.
out.println("Sorry, this servlet requires a <TT>method</TT> " +
"parameter with one of these values: " +
"http, socket, rmi");
return;
}
// Print the HTML code to generate the applet.
// Choose the applet code based on the method parameter.
// Provide a user parameter if we know the remote user.
out.println("<APPLET CODE=" + applet + " CODEBASE=/chat/ " +
"WIDTH=500 HEIGHT=170>");
if (user != null)
out.println("<PARAM NAME=user VALUE=\"" + user + "\">");
out.println("</APPLET>");
out.println("</BODY></HTML>");
}
}
Jeg har rettet det samme i *ChatApplet f.eks. HttpChatApplet:
import java.applet.*;
import java.awt.*;
import java.io.*;
import java.net.*;
import java.util.*;
import com.oreilly.servlet.HttpMessage;
public class HttpChatApplet extends Applet implements Runnable {
TextArea text;
Label label;
TextField input;
Thread thread;
String user;
public void init() {
// Check if this applet was loaded directly from the filesystem.
// If so, explain to the user that this applet needs to be loaded
// from a server in order to communicate with that server's servlets.
URL codebase = getCodeBase();
if (!"http".equals(codebase.getProtocol())) {
System.out.println();
System.out.println("*** Whoops! ***");
System.out.println("This applet must be loaded from a web server.");
System.out.println("Please try again, this time fetching the HTML");
System.out.println("file containing this servlet as");
System.out.println("\"
http://server:port/file.html\".");
System.out.println();
System.exit(1); // Works only from appletviewer
// Browsers throw an exception and muddle on
}
// Get this user's name from an applet parameter set by the servlet
// We could just ask the user, but this demonstrates a
// form of servlet->applet communication.
user = getParameter("user");
if (user == null) user = "anonymous";
// Set up the user interface...
// On top, a large TextArea showing what everyone's saying.
// Underneath, a labeled TextField to accept this user's input.
text = new TextArea();
text.setEditable(false);
label = new Label("Say something: ");
input = new TextField();
input.setEditable(true);
setLayout(new BorderLayout());
Panel panel = new Panel();
panel.setLayout(new BorderLayout());
add("Center", text);
add("South", panel);
panel.add("West", label);
panel.add("Center", input);
}
public void start() {
thread = new Thread(this);
thread.start();
}
String getNextMessage() {
String nextMessage = null;
while (nextMessage == null) {
try {
URL url = new URL(getCodeBase(), "/chat/ChatServlet");
HttpMessage msg = new HttpMessage(url);
InputStream in = msg.sendGetMessage();
DataInputStream data = new DataInputStream(
new BufferedInputStream(in));
nextMessage = data.readLine();
}
catch (SocketException e) {
// Can't connect to host, report it and wait before trying again
System.out.println("Can't connect to host: " + e.getMessage());
try { Thread.sleep(5000); } catch (InterruptedException ignored) { }
}
catch (FileNotFoundException e) {
// Servlet doesn't exist, report it and wait before trying again
System.out.println("Resource not found: " + e.getMessage());
try { Thread.sleep(5000); } catch (InterruptedException ignored) { }
}
catch (Exception e) {
// Some other problem, report it and wait before trying again
System.out.println("General exception: " +
e.getClass().getName() + ": " + e.getMessage());
try { Thread.sleep(1000); } catch (InterruptedException ignored) { }
}
}
return nextMessage + "\n";
}
public void run() {
while (true) {
text.appendText(getNextMessage());
}
}
public void stop() {
thread.stop();
thread = null;
}
void broadcastMessage(String message) {
message = user + ": " + message; // Pre-pend the speaker's name
try {
URL url = new URL(getCodeBase(), "/chat/ChatServlet");
HttpMessage msg = new HttpMessage(url);
Properties props = new Properties();
props.put("message", message);
msg.sendPostMessage(props);
}
catch (SocketException e) {
// Can't connect to host, report it and abandon the broadcast
System.out.println("Can't connect to host: " + e.getMessage());
}
catch (FileNotFoundException e) {
// Servlet doesn't exist, report it and abandon the broadcast
System.out.println("Resource not found: " + e.getMessage());
}
catch (Exception e) {
// Some other problem, report it and abandon the broadcast
System.out.println("General exception: " +
e.getClass().getName() + ": " + e.getMessage());
}
}
public boolean handleEvent(Event event) {
switch (event.id) {
case Event.ACTION_EVENT:
if (event.target == input) {
broadcastMessage(input.getText());
input.setText("");
return true;
}
}
return false;
}
}
Og det var kun lige det jeg kunne huske !
:-)
Ny bruger
Nybegynder
Opret
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