Request

(1) 原理

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(2)继承结构

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(3).方法的介绍

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(4).创建
Servlet 快速创建

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@WebServlet(urlPatterns =  "/ServletDemo1")
public class ServletDemo1 extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         //请求头
        Enumeration<String> headerNames = request.getHeaderNames();
        while (headerNames.hasMoreElements()) {
            String name = headerNames.nextElement();
            String header = request.getHeader(name);
            System.out.println(name+ "---" + header);
        }
        //获取头
        String header = request.getHeader("user-agent");
        String reforer = request.getHeader("reforer");
        System.out.println(reforer);
        //为什么使用 contains
        if (header.contains("chrome")){
            System.out.println("谷歌来了");
        }
        //请求行
        String method = request.getMethod();
        System.out.println(method);
        System.out.println(request.getContextPath());
        //比较URL 和 URI 的区别
        System.out.println(request.getRequestURI());
        System.out.println(request.getRequestURL());
        //GET
        ///MyWeb_war
        ///MyWeb_war/ServletDemo1
        //http://localhost:8080/MyWeb_war/ServletDemo1