如何在拦截器中获取url路径里面@PathVariable的参数值

Map pathVariables = (Map) request.getAttribute(
HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
String classId = (String)pathVariables.get("classId");

    // 获取某个班级下面的学生列表
    @RequestMapping("/classes/{classId}/students")
    public String list(@PathVariable String classId){
        return "学生列表";
    }

package com.example.demo;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.ModelAndView;
import java.util.Map;
public class SpringMVCInterceptor implements HandlerInterceptor {
 @Override
 public boolean preHandle(HttpServletRequest request,
   HttpServletResponse response, Object handler) throws Exception {
  Map pathVariables = (Map) request.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
  String chatbotId = (String)pathVariables.get("classId");
  System.out.println("classId: " + classId);
  if ("1234".equals(classId))
   return true;
  return false;
 } 
 
 @Override
 public void postHandle(HttpServletRequest request,
   HttpServletResponse response, Object handler,
   ModelAndView modelAndView) throws Exception {
  // TODO Auto-generated method stub  
 }
 @Override
 public void afterCompletion(HttpServletRequest request,
   HttpServletResponse response, Object handler, Exception ex)
 throws Exception {
  // TODO Auto-generated method stub  
 } 
}

package com.example.demo;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
@Configuration
public class MvcInterceptorConfig extends WebMvcConfigurationSupport{
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new SpringMVCInterceptor()).addPathPatterns("/chatbot/**");
        super.addInterceptors(registry);
    }
}

@RequestMapping(value = "/page/{id}", method = RequestMethod.GET)     

Tool tool = new Tool();
tool.setUrls(new String[]{"finance/account/loanDownExcel/cur","finance/account/loanDownExcel/all"});

@RequestMapping("accountlog/loanDownExcel/{type}")
public void exportAccountLogExcel(@PathVariable("type")  String type)throws Exception {}

public void exportAccountLogExcel(@PathVariable   String type)throws Exception {}