概述

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response的API

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代码一【请求重定向】

是一种资源跳转方式，可以在服务器之间进行资源跳转
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@WebServlet("/servlet/ResponseDemo2")
public class ResponseDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        /*//设置状态码
        response.setStatus(302);
        //设置响应头---location(302+location实现请求重定向)
        response.setHeader("location","https://www.tmooc.cn/");*/
        //请求重定向
        response.sendRedirect("https://www.tmooc.cn/");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

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代码二【定时刷新】

@WebServlet("/servlet/ResponseDemo1")
public class ResponseDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //解决乱码问题
        response.setContentType("text/html;charset=utf8");
        //等待提示
        response.getWriter().write("恭喜注册成功等待3秒钟跳转到首页！！！");
        //定时刷新(时间单位是s)
        response.setHeader("refresh","3;url=https://www.tmooc.cn/");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request, response);
    }
}

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控制不使用缓存【每次拿到的都是新的东西】

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@WebServlet("/servlet/ResponseDemo1")
public class ResponseDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //控制不使用缓存（每次都访问服务器得到新的数据）
        /*response.setDateHeader("Expires",-1);
        response.setHeader("Cache-control","no-cache");
        response.setHeader("pragma","no-cache");*/
        //控制使用缓存【使用IE浏览器测试】
        response.setDateHeader("Expires",System.currentTimeMillis());
        response.setHeader("Cache-control","max-Age=5");//缓存生效时间为5s
        //如果不使用缓存，说明每一次时间值都是最新的
        Date date=new Date();
        String time = date.toLocaleString();
        response.getWriter().write(time);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request, response);
    }
}