1、方法一：注解参数注入

    @RequestMapping(value = "/helloHystrixA/{string}", method = RequestMethod.GET)
    @HystrixCommand(fallbackMethod = "testFallback", // 请求失败降级回调方法，值为方法名，不需要括号
        commandProperties = {// 针对单个方法的配置
            @HystrixProperty(name = "circuitBreaker.enabled", value = "true"), // 开启熔断器，可不加默认为true
            @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage", value = "50"), // 请求错误超过50%，开启熔断器
            @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "10"), // 一个周期(十秒)内超过10个请求才进行进行容错率判断
            @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "10000"),// 开启熔断器后过10秒再尝试访问
        })
    public String helloHystirxA(@PathVariable String string) {
        return "Nacos服务发现：远端调用成功！ result="
            + restTemplate.getForObject("http://nacos.provider.demo/hello/" + string, String.class);