RequestInfoServlet接口： 提取HTTP请求报头信息

代码块
```package com.foreknow.controller;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *RequestInfoServlet接口： 提取HTTP请求报头信息
 * @author Administrator
 *
 */
public class RequestInfoServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //服务器端先客户端响应的内容的类型
        resp.setContentType("text/html;charset=utf-8");
        
        //req.getContextPath();获取上下文的路径（当前项目的路径）
        String contextPath=req.getContextPath();
        
        //PrintWriter可以在网页中输出内容
        PrintWriter out=resp.getWriter();
        out.println("获取工程路径："+contextPath+"<br>");
        out.println("获取客户端向服务器端请求的方法："+req.getMethod()+"<br>");
        out.println("servlet的映射地址："+req.getRequestURI());
        out.flush();
        out.close();
    }
    
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        
    }

}