后端查询所有商品大类接口实现

package com.java1234.controller;

import com.java1234.entity.BigType;
import com.java1234.entity.R;
import com.java1234.service.IBigTypeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 商品大类Co