大概原理：通过反射解析注解 @SentinelResource信息完成调用，处理方法，类似AOP编程

处理方法的返回类型要保持一致，参数和顺序保持一致， 可以在参数列表最后加

com.alibaba.csp.sentinel.slots.block.BlockException;

    /**
     * 如果不在同类，需要指明类名和方法名并且方法必须是静态方法
     */
    @GetMapping("/add2")
    @SentinelResource(value = "add", blockHandlerClass = {FlowContrlHandler.class}, blockHandler = "flow")
    public String add2() {
        System.out.println("下单成功！开始远程调用库存服务");
        return stockServiceFeign.reduct();
    }

    /**
     * 如果在同类，只需要指明方法名
     */
    @GetMapping("/flow")
    @SentinelResource(value = "flow", blockHandler = "flowControlHandler")
    public String flow() {
        return "正常访问";
    }
    
    public String flowControlHandler(BlockException e) {
        return "Sentinel: 请求频繁！请稍后再试！";
    }

package com.ldj.cloud.order.handler;

import com.alibaba.csp.sentinel.slots.block.BlockException;

/**
 * User: ldj
 * Date: 2024/4/18
 * Time: 23:51
 * Description: No Description
 */
public class FlowContrlHandler {

    public static String flow(BlockException e) {
        return "Sentinel_Static: 请求频繁！请稍后再试！";
    }
}