request 获取请求头数据

package package02;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

@WebServlet("/requestDemo2")
public class RequestDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //演示获取请求头数据

        //获取所有的请求头名称
        Enumeration<String> headerNames = request.getHeaderNames();
        //遍历
        while (headerNames.hasMoreElements()){
            //获取名字
            String name = headerNames.nextElement();
            //把名字传到这里面,根据名称获取请求头的值
            String value = request.getHeader(name);
            System.out.println(name+"---"+value);
        }
    }
}

演示请求头数据: user-agent

@WebServlet("/RequestDemo3")
public class RequestDemo3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //演示请求头数据: user-agent

        String agent = request.getHeader("user-agent");

       //判断agent的浏览器版本
        if (agent.contains("Chrome")) {
            //谷歌
            System.out.println("谷歌来了....");
        }else {
            System.out.println("火狐来了....");
        }

    }
}