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 {}