forked from usf-cs272-fall2022/lectures
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ReverseServer.java
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/
ReverseServer.java
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package edu.usfca.cs272;
import java.io.IOException;
import java.io.PrintWriter;
import org.apache.commons.text.StringEscapeUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHandler;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
/**
* A simple example of using Jetty and servlets to use an HTML form.
*
* @author CS 272 Software Development (University of San Francisco)
* @version Fall 2022
*/
public class ReverseServer {
/** The hard-coded port to run this server. */
public static final int PORT = 8080;
/**
* The logger to use (Jetty is configured via the pom.xml to use Log4j2)
*/
public static Logger log = LogManager.getLogger();
/**
* Sets up a Jetty server configured to use the servlets defined in this class.
*
* @param args unused
* @throws Exception if unable to start web server
*/
public static void main(String[] args) throws Exception {
Server server = new Server(PORT);
ServletHandler handler = new ServletHandler();
handler.addServletWithMapping(ReverseGetServlet.class, "/get_reverse");
handler.addServletWithMapping(ReversePostServlet.class, "/post_reverse");
server.setHandler(handler);
server.start();
log.info("Server: {} with {} threads", server.getState(), server.getThreadPool().getThreads());
server.join();
}
/**
* Outputs and responds to HTML form.
*/
public static class ReverseGetServlet extends HttpServlet {
/** Class version for serialization, in [YEAR][TERM] format (unused). */
private static final long serialVersionUID = 202240;
/** The title to use for this webpage. */
private static final String TITLE = "Reverse";
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
log.info(request);
String html = """
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>%1$s</title>
</head>
<body>
<h1>%1$s</h1>
<form method="get" action="/get_reverse">
<p>
<input type="text" name="word" size="50"></input>
</p>
<p>
<button>Reverse</button>
</p>
</form>
<pre>
%2$s
</pre>
</body>
</html>
""";
String reversed = request.getParameter("word");
log.info("{}", reversed);
if (reversed == null || reversed.isBlank()) {
reversed = "";
}
else {
reversed = new StringBuilder(reversed).reverse().toString();
reversed = StringEscapeUtils.escapeHtml4(reversed);
}
// wolf, stressed, pool
// <b>hiii</b>
// >b/<iiih>b<
PrintWriter out = response.getWriter();
out.printf(html, TITLE, reversed, Thread.currentThread().getName());
response.setContentType("text/html");
response.setStatus(HttpServletResponse.SC_OK);
}
/*
* Pros: Nice all-in-one method, good for simple forms, easy to re-display
* the form.
*
* Cons: Method has to both handle generating HTML and processing data. Can
* end up too complex for more complicated forms. Parameters in URL.
*/
}
/**
* Outputs and responds to HTML form.
*/
public static class ReversePostServlet extends HttpServlet {
/** Class version for serialization, in [YEAR][TERM] format (unused). */
private static final long serialVersionUID = 202240;
/** The title to use for this webpage. */
private static final String TITLE = "Reverse";
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
log.info(request);
String html = """
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>%1$s</title>
</head>
<body>
<h1>%1$s</h1>
<form method="post" action="/post_reverse">
<p>
<input type="text" name="word" size="50"></input>
</p>
<p>
<button>Reverse</button>
</p>
</form>
</body>
</html>
""";
PrintWriter out = response.getWriter();
out.printf(html, TITLE, Thread.currentThread().getName());
response.setContentType("text/html");
response.setStatus(HttpServletResponse.SC_OK);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
log.info(request);
String html = """
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>%1$s</title>
</head>
<body>
<h1>%1$s</h1>
<pre>
%2$s
</pre>
<p>(<a href="/post_reverse">back to form</a>)</p>
</body>
</html>
""";
String reversed = request.getParameter("word");
log.info("{}", reversed);
if (reversed == null || reversed.isBlank()) {
reversed = "";
}
else {
reversed = new StringBuilder(reversed).reverse().toString();
reversed = StringEscapeUtils.escapeHtml4(reversed);
}
PrintWriter out = response.getWriter();
out.printf(html, TITLE, reversed, Thread.currentThread().getName());
response.setContentType("text/html");
response.setStatus(HttpServletResponse.SC_OK);
}
/*
* Pros: Possible to separate logic generating HTML and processing data for
* complex cases. No parameters in URL.
*
* Cons: For this simple example, duplicate display logic. Not re-displaying
* form after generating result.
*/
}
}