实现Servlet接口来开发Servlet程序

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

//实现Servlet接口来开发Servlet程序
public class Demo3 implements Servlet {

    @Override
    public void destroy() {
        // TODO Auto-generated method stub

    }

    @Override
    public ServletConfig getServletConfig() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public String getServletInfo() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void init(ServletConfig arg0) throws ServletException {
        // TODO Auto-generated method stub

    }

    @Override
    public void service(ServletRequest request, ServletResponse response)
            throws ServletException, IOException {
        //取得服务端向浏览器的输出流对象
        PrintWriter pw = response.getWriter();
        pw.write("welcome to java web coure!");

    }

}

web.xml

<servlet>
    <servlet-name>Demo3</servlet-name>
    <servlet-class>cn.web.http.Demo3</servlet-class>
  </servlet>

      <servlet-mapping>
    <servlet-name>Demo3</servlet-name>
    <url-pattern>/Demo3</url-pattern>
  </servlet-mapping>