为什么我设置拦截器后显示无法访问 ,这是根据视频老师一样打的！

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	id="WebApp_ID" version="3.0">
	<display-name>FileDemo</display-name>
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
	<!--注册过滤器 -->
	<filter>
		<filter-name>filter</filter-name>
		<filter-class>fillter.doFillter</filter-class>


		<init-param>
			<param-name>chaset</param-name>
			<param-value>UTF-8</param-value>
		</init-param>

	</filter>
	<!-- 拦截请求配置 -->
	<filter-mapping>
		<filter-name>filter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
</web-app>

dofilter

package fillter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

//过滤器类
public class doFillter implements Filter {
	private FilterConfig config;

	public FilterConfig getConfig() {
		return config;
	}

	public void setConfig(FilterConfig config) {
		this.config = config;
	}

	@Override
	public void destroy() {

	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		
		HttpServletRequest hrequest = (HttpServletRequest) request;
		HttpServletResponse hresponse = (HttpServletResponse) response;
		String str=(String) hrequest.getSession().getAttribute("loginUser");
		System.out.println(str);
		if (str==null) {
			hresponse.sendRedirect("/FileDemo/WebContent/index.jsp");
			return;
		} else {
			request.setCharacterEncoding(config.getInitParameter("chaset"));
			chain.doFilter(request, response);
			return;
		}
	}

	@Override
	public void init(FilterConfig config) throws ServletException {
		this.config = config;
	}

}