sprng mvc过滤器 过滤重定向和ajax访问方式的session是否存在

java代码
package com.bjhm.util;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.filter.OncePerRequestFilter;

public class SessionFilter extends OncePerRequestFilter {

@Override
protected void doFilterInternal(HttpServletRequest request,
        HttpServletResponse response, FilterChain filterChain)
        throws ServletException, IOException {
    //request.getSession().setAttribute("loginedUser", "ssss");
    // 不过滤的uri
    String[] notFilter = new String[] {"tmLogin","logOut"};
    // 请求的uri
    String uri = request.getRequestURI();
    // 从session中获取登录者id
    String ho_user_id = (String)request.getSession().getAttribute("ho_user_id");
    /