SpringCloud学习笔记16——高级篇之SpringCloud Alibaba Sentinel实现熔断与限流

8.SentinelResource配置

①按资源名称限流

(1)新建controller

package com.hry.springcloud.alibaba.controller;


import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class RateLimitController {
    @GetMapping(value = "/byResource")
    @SentinelResource(value = "byResource",blockHandler = "handleException")
    public CommonResult byResource(){
        return new CommonResult(200,"按资源名称限流测试OK",new Payment(202L,"serial001"));
    }

    public CommonResult handleException(BlockException exception){
        return new CommonResult(444,exception.getClass().getCanonicalName()+"\t 服务不可用");
    }
}

(2)新建流控规则

(3)测试

②按资源名称限流

(1)在RateLimitController添加方法

@GetMapping("/rateLimit/byUrl")
    @SentinelResource(value = "byUrl")
    public CommonResult byUrl(){
        return new CommonResult(200,"按url限流测试OK",new Payment(2020L,"serial002"));
    }

(2)新建流控规则

(3)测试

③问题

跟之前的Hystrix一样

④客户自定义限流处理逻辑

(1)新建CustomerBlockHandler类

package com.hry.springcloud.alibaba.handler;

import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;

public class CustomerBlockHandler {
    public static CommonResult handlerException(BlockException exception){
        return new CommonResult(1234567,"按客户自定义全局-----Global-----1");
    }

    public static CommonResult handlerException2(BlockException exception){
        return new CommonResult(7654321,"按客户自定义全局-----Global-----2");
    }
}

(2)在RateLimitController添加方法

@GetMapping("/rateLimit/customerBlockHandler")
    @SentinelResource(value = "customerBlockHandler",
            blockHandlerClass = CustomerBlockHandler.class,   //指定我们刚才创建的类
            blockHandler = "handlerException2")               //使用第二个方法处理
    public CommonResult customerBlockHandler(){
        return new CommonResult(200,"自定义",new Payment(2020L,"serial003"));
    }

(3)新建流控规则

(4)测试

9.服务熔断

Sentinel+Ribbon+OpenFeign+fallback

Ribbon：

①Sentinel服务熔断无配置

(1)cloudalibaba-provider-payment9003，cloudalibaba-provider-payment9004

这个与9002相似不同处下面会给出，其他直接复制原来的9002即可

controller

package com.hry.springcloud.alibaba.controller;

import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;

@RestController
public class PaymentController {
    @Value("${server.port}")
    private String serverPort;

    public static HashMap<Long, Payment> hashMap = new HashMap<>();

    //模拟dao层  偷懒
    static {
        hashMap.put(1001L,new Payment(1001L,"1001abcd"));
        hashMap.put(1002L,new Payment(1002L,"1002abcd"));
        hashMap.put(1003L,new Payment(1003L,"1003abcd"));
    }

    @GetMapping(value = "/paymentSQL/{id}")
    public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id){
        Payment payment = hashMap.get(id);
        CommonResult<Payment> result = new CommonResult<Payment>(200,"from MySQL , serverPort: "+serverPort,payment);
        return result;
    }
}

(2)cloudalibaba-consumer-nacos-order84

与83相似，没有给出的的都与83内容一致。
yml

server:
  port: 84

spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #配置nacos地址
    sentinel:
      transport:
        #配置sentinel dashboard地址
        dashboard: localhost:8080
        #默认8719端口，端口被占用会自动从8719开始依次+1开始扫描，直至找到未被占用的端口
        port: 8719
service-url: 
  nacos-user-service: http://nacos-payment-provider

controller

package com.hry.springcloud.alibaba.controller;

import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;

@RestController
public class CircleBreakerController {
    public static final String SERVICE_URL = "http://nacos-payment-provider";

    @Resource
    private RestTemplate restTemplate;

    @RequestMapping(value = "/consumer/fallback/{id}")
    @SentinelResource(value = "fallback") //不配置的
    public CommonResult<Payment> fallback(@PathVariable("id") Long id){
        CommonResult<Payment> result = restTemplate.getForObject(SERVICE_URL+"/paymentSQL/"+id,CommonResult.class,id);

        if (id == 1004){
            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;
    }
}

(3)测试

1004

其他

②Sentinel服务熔断只配置fallback

(1)修改controller

修改

@SentinelResource(value = "fallback",fallback = "handlerFallback") //fallback只负责业务异常

添加方法

	public CommonResult<Payment> handlerFallback(@PathVariable("id") Long id,Throwable e){
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(444,"handlerFallback兜底方法 , 异常"+e.getMessage(),payment);
    }

(2)测试

③Sentinel服务熔断只配置blockHandler

(1)修改controller

修改

@SentinelResource(value = "fallback",blockHandler = "blockHandler") //blockHandler只负责sentinel控制台配置违规

添加方法

public CommonResult<Payment> blockHandler(@PathVariable("id") Long id, BlockException blockException){
        Payment payment = new Payment(id,"null");
        return new CommonResult<>(4444,"blockHandler-sentinel限流，无此流水 , blockException"+blockException.getMessage(),payment);
    }

(2)添加流控规则（或降级规则都可）

(3)测试

可以看到，流量异常能够处理，但是运行时异常无法解决，是默认的

④Sentinel服务熔断配置fallback和blockHandler

(1)修改controller

@SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler")

(2)添加流控规则（或降级规则都可）

(3)测试

这次完美了

①-④注解：

⑤Sentinel服务熔断exceptionsToIgnore

(1)修改controller 在注解中添加exceptionsToIgnore 并指定哪些 异常

@SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler",exceptionsToIgnore = {IllegalArgumentException.class})

(2)测试

我们配置忽略非法参数异常之后找1004，会正常报错。进到error page

OpenFeign：

①Sentinel服务熔断OpenFeign

(1)修改84的yml

添加配置

#激活
feign:
  sentinel:
    enabled: true

(2)修改84的主启动类

添加注解

@EnableFeignClients

(3)修改84的业务类

新建service包

新建接口PaymentService

package com.hry.springcloud.alibaba.service;

import com.hry.springcloud.alibaba.service.Impl.PaymentServiceImpl;
import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@FeignClient(value = "nacos-payment-provider",fallback = PaymentServiceImpl.class)
public interface PaymentService {

    @GetMapping(value = "/paymentSQL/{id}")
    public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id);
}

新建实现类PaymentServiceImpl

package com.hry.springcloud.alibaba.service.Impl;

import com.hry.springcloud.alibaba.service.PaymentService;
import com.hry.springcloud.entities.CommonResult;
import com.hry.springcloud.entities.Payment;
import org.springframework.stereotype.Component;

@Component
public class PaymentServiceImpl implements PaymentService {
    @Override
    public CommonResult<Payment> paymentSQL(Long id) {
        return new CommonResult<>(55555,"服务降级返回---来自PaymentServiceImpl",new Payment(id,"error"));
    }
}

修改controller，添加如下代码

	@Resource
    private PaymentService paymentService;

	@GetMapping(value = "/consumer/paymentSQL/{id}")
    public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id){
        return paymentService.paymentSQL(id);
    }

(4)测试

关闭9003，服务降级

10.几个熔断框架比较