servlet

 <servlet>
            <servlet-name>q</servlet-name>
            <servlet-class>com.ahkds.BestServlet</servlet-class>
            <load-on-startup>1</load-on-startup>
        </servlet>
    <servlet-mapping>
        <servlet-name>q</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

@WebServlet(urlpattern="/1" ,loadonstart=0)
@WebServlet(urlpattern={"/1","/2" },loadonstart=0)

request.getParameter("name"）
request.getParameterValues("array")
request.getParameterMap()

request.setAttrbute("extra","夹带私货")
RequestDispartcher dispartcher=request.getrequestDispatcher("/servlet");
dispartcher.forword(request,response);
转发
request.getRequestDispatcher("/servlet").forward("request,response)

乱码
request.setCharacterEncoding("utg-8")
response.setHeader ("refersh","5","http:www.baidu.com")
response.setHeader("content-type","test/plain;charset=utf-8")

重定向
response.setStatus(302);
response.setHeader("location","/wangServlet")
简化为respoonset.setRedirect("/wangServlet")

下载附件
response.setHeader("content-disposition","attachment","filename=x"+name)

context.getRealPath