SpringCloud Hystrix

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spring

SpringCloud Hystrix

Hystrix是一个用于处理分布式系统的延迟和容错的开源库，在分布式系统里，许多依赖不可避免的会调用失败，比如超时、异常等。
Hystrix能够保证在一个依赖出问题的情况下，不会导致整体服务失败，避免级联故障，以提高分布式系统的弹性。
服务异常时Hystrix会向调用方返回一个符合预期的、可处理的备选响应（FallBack），而不是长时间的等待或者抛出调用方无法处理的异常

服务熔断

新建服务提供者

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

yml

server:
  port: 8001

#mybatis配置
mybatis:
  config-location: classpath:mybatis/mybatis.cfg.xml      # mybatis配置文件所在路径
  type-aliases-package: io.imwj.springcloud.entity        # 所有Entity别名类所在包
  mapper-locations:
    - classpath:mybatis/mapper/**/*.xml                       # mapper映射文件

#mysql数据源配置
spring:
  application:
    name: microservicecloud-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource            # 当前数据源操作类型
    driver-class-name: org.gjt.mm.mysql.Driver              # mysql驱动包
    url: jdbc:mysql://localhost:3306/cloudDB01              # 数据库名称
    username: root
    password: 123456
    dbcp2:
      min-idle: 5                                           # 数据库连接池的最小维持连接数
      initial-size: 5                                       # 初始化连接数
      max-total: 5                                          # 最大连接数
      max-wait-millis: 200                                  # 等待连接获取的最大超时时间

# 打印sql语句
logging:
  level:
    io.imwj.springcloud: debug
    io.imwj.springcloud.dao: trace

#客户端注册进eureka服务列表内
eureka:
  client:
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/
  instance:
    instance-id: microservicecloud-dept8001-hystrix
    prefer-ip-address: true     #访问路径可以显示IP地址

info:
  app.name: microservicecloud
  company.name: blog.imwj.club
  build.artifactId: $project.artifactId$
  build.version: $project.version$

controller增加注解@HystrixCommand(fallbackMethod = "processHystrix_Get")

一旦/dept/get方法查询为null就会抛出异常，然后调用备选的processHystrix_Get方法

@RestController
public class DeptController {

    @Autowired
    private DeptService deptService;

    @Autowired
    private DiscoveryClient client;

    @HystrixCommand(fallbackMethod = "processHystrix_Get")
    @RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
    public Dept get(@PathVariable Long id){
        Dept dept = deptService.get(id);
        if(dept == null){
            throw new RuntimeException("服务异常！");
        }
        return dept;
    }

    public Dept processHystrix_Get(@PathVariable("id") Long id){
        return new Dept().setDeptno(id)
                .setDname("服务异常延迟！")
                .setDb_source("在数据库中没有查询到数据！");
    }
}

启动类增加注解

@EnableCircuitBreaker

@EnableEurekaClient//注册到Eureka中
@EnableCircuitBreaker//对hystrixR熔断机制的支持
@SpringBootApplication
public class DeptProvider8001_Hystrix_App {

    public static void main(String[] args) {
        SpringApplication.run(DeptProvider8001_Hystrix_App.class, args);
    }
}

服务降级

api项目中增加一个实现类DeptClientServiceFallbackFactory

/**
 * 此处只处理get接口的降级
 * @author langao_q
 * @create 2020-04-11 10:30
 */
@Component
public class DeptClientServiceFallbackFactory implements FallbackFactory<DeptClientService> {
    @Override
    public DeptClientService create(Throwable throwable) {
        return new DeptClientService() {
            @Override
            public Dept get(long id) {
                return new Dept().setDeptno(id)
                        .setDname("服务异常延迟！")
                        .setDb_source("在数据库中没有查询到数据！");
            }

            @Override
            public List<Dept> list() {
                return null;
            }

            @Override
            public boolean add(Dept dept) {
                return false;
            }
        };
    }
}

修改DeptClientService

@FeignClient(value = "MICROSERVICECLOUD-DEPT",fallbackFactory=DeptClientServiceFallbackFactory.class)
public interface DeptClientService {

    @RequestMapping(value = "/dept/get/{id}",method = RequestMethod.GET)
    public Dept get(@PathVariable("id") long id);

    @RequestMapping(value = "/dept/list",method = RequestMethod.GET)
    public List<Dept> list();

    @RequestMapping(value = "/dept/add",method = RequestMethod.POST)
    public boolean add(Dept dept);
}

consumer-dept-fegin消费者yml增加

feign: 
  hystrix: 
    enabled: true

服务监控

新建监控项目

        <!-- hystrix和 hystrix-dashboard相关-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
        </dependency>

server:
  port: 9001

@SpringBootApplication
@EnableHystrixDashboard
public class DeptConsumer_DashBoard_App {

    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer_DashBoard_App.class, args);
    }
}

被监控项目

使用我们之前熔断步骤新建的microservicecloud-provider-hystrix-8001

        <!-- actuator监控信息完善 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--hystrix-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>

测试

图形解析

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最后编辑时间为: 2020/04/11 11:58