实现步骤：
（1）创建servlet BrowserServer
（2）调用HttpServletRequest对象的getServerName()方法获取服务器名称
（3）调用HttpServletRequest对象的getServerPort()方法获取服务器端口
（4）首先调用getServletContext()方法获取ServletContext对象，然后调用ServletContext对象的getServerInfo()方法获取服务器环境信息名称、版本信息
（5）利用HttpServletResponse对象的PrintWriter将信息显示到页面
package example.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class BrowserServer */ @WebServlet("/BrowserServer") public class BrowserServer extends HttpServlet { private static final long serialVersionUID = 1L; protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=utf-8"); PrintWriter out=response.getWriter(); ServletContext context=getServletContext(); out.println("<html>"); out.println("<head>"); out.println("<title>服务器信息</title>"); out.println("</head>"); out.println("<body>"); out.println("<h3>服务器名称："+request.getServerName()+"</h3>"); out.println("<h3>服务器端口："+request.getServerPort()+"</h3>"); out.println("<h3>"+context.getServerInfo()+"</h3>"); out.println("</body>"); out.println("<html>"); out.close(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request,response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request,response); } }