Java 过滤器

web.xml文件中

  <filter>
  <filter-name>filterTest1</filter-name>
  <filter-class>filter.FilterTest</filter-class>
  <init-param>
      <param-name>encoding</param-name>
      <param-value>utf8</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>filterTest1</filter-name>
  <url-pattern>/index.jsp</url-pattern>
</filter-mapping>

//FilterTest.java

public class FilterTest implements Filter {
      
    private FilterConfig conf = null;
    public void destroy() {
        // TODO Auto-generated method stub
          
        System.out.println("filter destroy");
    }
    public void doFilter(ServletRequest arg0, ServletResponse arg1,
            FilterChain arg2) throws IOException, ServletException {
        // TODO Auto-generated method stub
        System.out.println("in filter");
        arg2.doFilter(arg0, arg1);
        System.out.println(arg0.getParameter("encoding"));
    }
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub
        conf = arg0;
        System.out.println("init filter");
        System.out.println("Param: " + conf.getInitParameter("encoding"));
    }
}