今天在用struts2寫一個自定義過濾器的時候發現想要過濾的請求一直沒有進入過濾器，一直覺得奇怪了。

在web.xml中就是這樣配置的。

	<filter>
		<filter-name>login filter</filter-name>
		<filter-class>com.danale.filter.LoginFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>login filter</filter-name>
		<url-pattern>*.jsp</url-pattern>
	 
	</filter-mapping>
 	<filter-mapping>
		<filter-name>login filter</filter-name>
		<url-pattern>*.action</url-pattern>
	 
	</filter-mapping>
 

過濾器是這麼寫的。

public class LoginFilter implements Filter {

	@Override
	public void destroy() {
		// TODO Auto-generated method stub
	}
	@Override
	public void doFilter(ServletRequest arg0, ServletResponse arg1,
			FilterChain arg2) throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) arg0;
		HttpServletResponse response = (HttpServletResponse) arg1;
		HttpSession session = request.getSession();
		String url = request.getRequestURI();
		String username = (String) session.getAttribute("username");
		if (username == null || username.equals("")) {
			if (url != null && !url.equals("")
					&& (url.indexOf("Login") < 0 && url.indexOf("login") < 0)) {
				response.sendRedirect("login.jsp");
				return;			}		}
		arg2.doFilter(arg0, arg1);
		return;
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		// TODO Auto-generated method stub

	}
}
 

後來把web.xml中的配置改成

	<filter>
		<filter-name>login filter</filter-name>
		<filter-class>com.danale.filter.LoginFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>login filter</filter-name>
		<url-pattern>/*</url-pattern>
	 
	</filter-mapping>
 

後面經過查詢，只需要把自定義的過濾器在web.xml中的配置放在struts過濾器的前面才會生效。如：

	<filter>
		<filter-name>login filter</filter-name>
		<filter-class>com.danale.filter.LoginFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>login filter</filter-name>
		<url-pattern>*.jsp</url-pattern>
	 
	</filter-mapping>
 	<filter-mapping>
		<filter-name>login filter</filter-name>
		<url-pattern>*.action</url-pattern>
	 
	</filter-mapping>
	<filter>
		<filter-name>struts-cleanup</filter-name>
		<filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class>
	</filter>
	<filter>
		<filter-name>struts2</filter-name>
		<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>struts2</filter-name>
		<url-pattern>*.action</url-pattern>
	</filter-mapping>