@toc

源码地址：gitee仓库地址

1、Ribbon系列

1.1 启动nacos和sentinel

1.2 创建两个服务提供者payment9003和payment9004

  新建cloudalibaba-provider-payment9003/9004两个一样的做法

  由于9003和9004除了端口号不一样，其他几乎一致，这里只演示9003端口的搭建方式。

  pom.xml

  <dependencies>        <!--SpringCloud ailibaba nacos -->        <dependency>            <groupId>com.alibaba.cloud</groupId>            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>        </dependency>        <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->            <groupId>com.atguigu.springcloud</groupId>            <artifactId>cloud-api-commons</artifactId>            <version>${project.version}</version>        </dependency>        <!-- SpringBoot整合Web组件 -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>        <!--日常通用jar包配置-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-devtools</artifactId>            <scope>runtime</scope>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>

  application.yml

 server:  port: 9003spring:  application:    name: nacos-payment-provider  cloud:    nacos:      discovery:        server-addr: localhost:8848 #配置Nacos地址management:  endpoints:    web:      exposure:        include: '*'

  记得修改不同的端口号

  主启动类

@SpringBootApplication@EnableDiscoveryClientpublic class PaymentMain9003{    public static void main(String[] args) {            SpringApplication.run(PaymentMain9003.class, args);    }}

  业务类

@RestControllerpublic class PaymentController{    @Value("${server.port}")    private String serverPort;    public static HashMap<Long,Payment> hashMap = new HashMap<>();    static    {        hashMap.put(1L,new Payment(1L,"28a8c1e3bc2742d8848569891fb42181"));        hashMap.put(2L,new Payment(2L,"bba8c1e3bc2742d8848569891ac32182"));        hashMap.put(3L,new Payment(3L,"6ua8c1e3bc2742d8848569891xt92183"));    }    @GetMapping(value = "/paymentSQL/{id}")    public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id)    {        Payment payment = hashMap.get(id);        CommonResult<Payment> result = new CommonResult(200,"from mysql,serverPort: "+serverPort,payment);        return result;    }}

  这里为了测试，并没有去连接数据库，模拟了几个数据，效果都是一样的。

  启动服务并测试业务类是否正常：http://localhost:9003/paymentSQL/1

  http://localhost:9004/paymentSQL/1

   两个服务提供者搭建成功。

1.3 搭建服务消费者order84

1.3.1 基础模块搭建

  新建cloudalibaba-consumer-nacos-order84

  pom.xml

<dependencies>        <!--SpringCloud ailibaba nacos -->        <dependency>            <groupId>com.alibaba.cloud</groupId>            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>        </dependency>        <!--SpringCloud ailibaba sentinel -->        <dependency>            <groupId>com.alibaba.cloud</groupId>            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>        </dependency>        <!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->        <dependency>            <groupId>com.atguigu.springcloud</groupId>            <artifactId>cloud-api-commons</artifactId>            <version>${project.version}</version>        </dependency>        <!-- SpringBoot整合Web组件 -->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>        <!--日常通用jar包配置-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-devtools</artifactId>            <scope>runtime</scope>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>    </dependencies>

  application.yml

server:  port: 84spring:  application:    name: nacos-order-consumer  cloud:    nacos:      discovery:        server-addr: localhost:8848    sentinel:      transport:        #配置Sentinel dashboard地址        dashboard: localhost:8080        #默认8719端口，假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口        port: 8719#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)service-url:  nacos-user-service: http://nacos-payment-provider

  主启动类

@EnableDiscoveryClient@SpringBootApplicationpublic class OrderNacosMain84{    public static void main(String[] args) {            SpringApplication.run(OrderNacosMain84.class, args);    }}

  业务类

  负载均衡配置：

@Configurationpublic class ApplicationContextConfig{    @Bean    @LoadBalanced    public RestTemplate getRestTemplate()    {        return new RestTemplate();    }}

  CircleBreakerController

@RestController@Slf4jpublic class CircleBreakerController{    public static final String SERVICE_URL = "http://nacos-payment-provider";    @Resource    private RestTemplate restTemplate;    @RequestMapping("/consumer/fallback/{id}")    @SentinelResource(value = "fallback")      public CommonResult<Payment> fallback(@PathVariable Long id)    {        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);        if (id == 4) {            throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常....");        }else if (result.getData() == null) {            throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常");        }        return result;    }}

  上面代码在id=1/2/3时正常，id=4时抛出IllegalArgumentException异常，大于4的时候抛出空指针异常。

  这里的测试目的：fallback管运行异常，blockHandler管配置违规

  上面并没有配置@SentinelResource,会直接给客户返回error页面，非常不友好。

1.3.2 只配置fallback

  @RequestMapping("/consumer/fallback/{id}")// @SentinelResource(value = "fallback")    @SentinelResource(value = "fallback",fallback = "handlerFallback")    public CommonResult<Payment> fallback(@PathVariable Long id)    {        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);        if (id == 4) {            throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常....");        }else if (result.getData() == null) {            throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常");        }        return result;    }// //fallback方法    public CommonResult handlerFallback(@PathVariable  Long id,Throwable e) {        Payment payment = new Payment(id,"null");        return new CommonResult<>(444,"兜底异常handlerFallback,exception内容 "+e.getMessage(),payment);    }

  注意：这里并没有配置sentinel。

  访问测试：

  http://localhost:84/consumer/fallback/1

  http://localhost:84/consumer/fallback/4

  http://localhost:84/consumer/fallback/5

  此时就执行指定的fallback，对调用者比较友好。

1.3.3 只配置blockHandler

   @RequestMapping("/consumer/fallback/{id}")    @SentinelResource(value = "fallback",blockHandler = "blockHandler")     public CommonResult<Payment> fallback(@PathVariable Long id)    {        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);        if (id == 4) {            throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常....");        }else if (result.getData() == null) {            throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常");        }        return result;    }// //fallback方法// public CommonResult handlerFallback(@PathVariable Long id,Throwable e) {// Payment payment = new Payment(id,"null");// return new CommonResult<>(444,"兜底异常handlerFallback,exception内容 "+e.getMessage(),payment);// }//    //blockHandler    public CommonResult blockHandler(@PathVariable  Long id, BlockException blockException) {        Payment payment = new Payment(id,"null");        return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException "+blockException.getMessage(),payment);    }

  这里需要配置下sentinel

  异常超过2次以后，断路器打开，断电跳闸，系统被保护。

  测试：

  第一次访问：http://localhost:84/consumer/fallback/4

  发现还是给了个error页面，注意，我们上面配置的是当异常数大于2的时候断路器才会打开。

  再访问几次。

   可以看到，被限流了。

1.3.4 fallback和blockHandler都配置

@RequestMapping("/consumer/fallback/{id}")// @SentinelResource(value = "fallback")// @SentinelResource(value = "fallback",fallback = "handlerFallback")// @SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler负责在sentinel里面配置的降级限流    @SentinelResource(value = "fallback",            fallback = "handlerFallback",            blockHandler = "blockHandler",    )    public CommonResult<Payment> fallback(@PathVariable Long id)    {        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL + "/paymentSQL/"+id,CommonResult.class,id);        if (id == 4) {            throw new IllegalArgumentException ("IllegalArgumentException,非法参数异常....");        }else if (result.getData() == null) {            throw new NullPointerException ("NullPointerException,该ID没有对应记录,空指针异常");        }        return result;    }    //fallback方法    public CommonResult handlerFallback(@PathVariable  Long id,Throwable e) {        Payment payment = new Payment(id,"null");        return new CommonResult<>(444,"兜底异常handlerFallback,exception内容 "+e.getMessage(),payment);    }// //blockHandler    public CommonResult blockHandler(@PathVariable  Long id, BlockException blockException) {        Payment payment = new Payment(id,"null");        return new CommonResult<>(445,"blockHandler-sentinel限流,无此流水: blockException "+blockException.getMessage(),payment);    }

   这里需要配置Sentinel流控

  配置解释：1秒只能处理1个请求，否则就限流。

  我们测试，http://localhost:84/consumer/fallback/4，一直频繁访问触发限流降级。

  ==结论：若 blockHandler 和 fallback 都进行了配置，则被限流降级而抛出 BlockException 时只会进入 blockHandler 处理逻辑。==

1.3.5 忽略属性配置

  我们给@SentinelResource注解添加配置exceptionsToIgnore = {IllegalArgumentException.class}

  此时如果我们传的参数id=4，则会忽略IllegalArgumentException异常。

  此时再访问：http://localhost:84/consumer/fallback/4

   此时异常打印到前台了，对用户不友好。

2、Feign系列

  我们一般服务调用都是使用OpenFeign的，在FeignClient中统一处理fallback

2.1 修改84模块。

  在服务消费者(order84)模块中引入OpenFeign

 <!--SpringCloud openfeign -->        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-openfeign</artifactId>        </dependency>

2.2 配置文件application.yml中激活Sentinel对Feign的支持

2.3 业务类

  带@FeignClient注解的业务接口

/** * 使用 fallback 方式是无法获取异常信息的， * 如果想要获取异常信息，可以使用 fallbackFactory参数 */@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallbackService.class)//调用中关闭9003服务提供者public interface PaymentService{    @GetMapping(value = "/paymentSQL/{id}")    public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id);}

  fallback = PaymentFallbackService.class的实现类

@Componentpublic class PaymentFallbackService implements PaymentService{    @Override    public CommonResult<Payment> paymentSQL(Long id)    {        return new CommonResult<>(44444444,"服务降级返回,-------PaymentFallbackService",new Payment(id, "errorSerial......"));    }}

  Controller:

  主启动类

  添加@EnableFeignClients启动Feign的功能

  访问测试：http://localhost:84/consumer/paymentSQL/1

  测试84调用9003，此时故意关闭9003微服务提供者，看84消费侧自动降级，不会被耗死

  关闭9003的服务提供者

  再次访问http://localhost:84/consumer/paymentSQL/1

  可以看到，已经出发了服务降级。返回的是我们在FeignClient接口中指定的falback。

3、三种熔断框架比较

  到此，Sentinel整合服务熔断的测试就介绍完了，关于Sentinel限流那块配置太多，不好细讲，最好去看看官网。我去年也发过限流的文章，去我SpringCloud Alibaba专栏里面找