防盗链

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        String referer = req.getHeader("Referer");
        if(referer==null|| !"http://localhost:8080/a".equals(referer)){
            PrintWriter writer = resp.getWriter();
            writer.write("防盗链");
        }else{
            PrintWriter writer = resp.getWriter();
            writer.write("路飞在跑");
        }
    }                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 

请求转发

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter writer = resp.getWriter();
        writer.write("a");
        req.getRequestDispatcher("/b").forward(req,resp);
    }

RequestDispatcher的include方法

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        PrintWriter writer = resp.getWriter();
        req.getRequestDispatcher("/c").include(req, resp);//匹配的Servlet代码writer.write("c");
        writer.write("a");
        req.getRequestDispatcher("/d").include(req, resp);//匹配的Servlet代码writer.write("d");
    }

    //页面显示：cad

Servlet第四篇【Request常用方法】

原文：https://www.cnblogs.com/kwdlh/p/12637268.html