一个简单的过滤器（filter）

有关于自己目前的对于filter的用法吧

 

备注，之下所写代码，不是测试代码，是直接把之前代码copy下来的，并不能直接运行，只是拿来当个借鉴

 

首先，是有关filter在web.xml配置文件中的配置

<filter>
		<filter-name>loginFilter</filter-name>
		<filter-class>filter.loginFilter</filter-class>
		<init-param>
			<param-name>ex</param-name>
			<param-value>login.jsp,.css,.eot,.woff,.ttf,.png,.jpg,Activity_User/login,Activity_Operator/login,.js,img</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>loginFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

接下来

public class loginFilter implements Filter{
	private Set<String> prefixIignores = new HashSet<String>();
	public void destroy() {
		// TODO Auto-generated method stub
		
	}

	public void doFilter(ServletRequest req1, ServletResponse resp1, FilterChain fc)
			throws IOException, ServletException {
		// TODO Auto-generated method stub
		HttpServletRequest req=(HttpServletRequest) req1;
		HttpServletResponse resp=(HttpServletResponse) resp1;
		if (canIgnore(req)) {
			fc.doFilter(req, resp);
			return;
		}
		if(req.getSession().getAttribute("operator")!=null||req.getSession().getAttribute("user")!=null) {
			fc.doFilter(req, resp);
		}
		else {
			resp.sendRedirect("http://localhost:8080/activity/login.jsp");
		}
	}

	public void init(FilterConfig c) throws ServletException {
		
		String ex = c.getInitParameter("ex");
		String[] ignoreArray = ex.split(",");
		for (String s : ignoreArray) {
			prefixIignores.add(s);
		}
	}
	private boolean canIgnore(HttpServletRequest request) {
		String url = request.getRequestURI();
		for (String ignore : prefixIignores) {
			if (url.endsWith(ignore)) {
				return true;
			}
		}
		return false;
	}


}