Use Servlet to write a hello world class

--web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<!-- Servlets -->
<servlet>
<servlet-name>hello</servlet-name>
<servlet-class>org.example.HelloAppEngineServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/helloappengine</url-pattern>
</servlet-mapping>

<!-- Default page to serve -->
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>

</web-app>

---Servlet

package org.example;

import java.io.IOException;
import javax.servlet.http.*;

public class HelloAppEngineServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
resp.setContentType("text/plain");
resp.setCharacterEncoding("UTF-8");
//resp.setContentType("text/html; charset=UTF-8");

resp.getWriter().println("Hello, world
");
resp.getWriter().println("Hello, 黃金甲一號");
}
}

---
result

http://localhost:8080/helloappengine



check the page source
---------------
Hello, world
Hello, 黃金甲一號