servlet中过滤器和监听器的基本使用

标签：servlet

一：filter过滤器

1．简单使用

public classSimpleFilter extends HttpServlet implements Filter {

       public void init(FilterConfig config)throws ServletException {

              String initParm=config.getInitParameter("ref");

              System.out.println("初始化过滤器："+initParm);

       }

       public void doFilter(ServletRequest arg0,ServletResponse arg1,

                     FilterChain chain) throwsIOException, ServletException {

                     System.out.println("****执行doFilter()方法前****");

                     chain.doFilter(arg0, arg1);

                     System.out.println("****执行doFilter()方法后****");

       }

       @Override

       public void destroy() {

              System.out.println("销毁过滤器");

       }

}

web.xml下配置过滤器

<filter>

     <filter-name>SimpleFilter</filter-name>

     <filter-class>com.cloud.day1.SimpleFilter</filter-class>

     <init-param>

            <param-name>ref</param-name>

            <param-value>Spring</param-value>

     </init-param>

  </filter>

  <filter-mapping>

     <filter-name>SimpleFilter</filter-name>

     <url-pattern>/*</url-pattern>

  </filter-mapping>

2.过滤编码

http://blog.csdn.net/dzy21/article/details/47042891

该文章详细使用了过滤器解决编码问题。

二：监听器

public class Demo2implements ServletContextListener {

       public void contextInitialized(ServletContextEventevent) {

              System.out.println("初始化："+event.getServletContext().getContextPath());

       }

       public voidcontextDestroyed(ServletContextEvent event) {

              System.out.println("销毁："+event.getServletContext().getContextPath());

       }

}

web.xml下配置监听器

<!-- 配置监听器 -->

  <listener>

     <listener-class>

            com.cloud.day1.Demo2

     </listener-class>

  </listener>

servlet中过滤器和监听器的基本使用

标签：servlet

原文地址：http://blog.csdn.net/dzy21/article/details/47321391