HttpServlet 是实现http协议的 Servlet
自定义Servlet
1. 继承 HttpServlet
2. 重新对应的请求方法
3. 配置对应web.xml
<servlet>
<servlet-name></servlet-name> <!--与servlet-mapping中的 servlet-name相同 -->
<servlet-class></servlet-class> <!--servlet所对应的 java类-->
<load-on-startup></load-on-startup> <!--启动优先级,越小优先级越高-->
</servlet>
<servlet-mapping>
<servlet-name></servlet-name> <!--与Servlet标签中的 servlet-name相同-->
<url-pattern></url-pattern> <!--访问该servlet的 url-->
</servlet-mapping>
@Override
protected void serviceHttpServletRequest req, HttpServletResponse resp super.req, resp;
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
long ;
if."GET"= this.;
if== -1Lthis., ;
else long ;
try = ."If-Modified-Since";
catch = -1L;
if< / 1000L * 1000Lthis., ;
this., ;
else .304;