hystrix主要作用在服務消費者,進行應用的保護,當請求的服務請求超時時,做出相應的處理,避免客戶端一直進行請求等待,避免在高併發的情況出現伺服器當機(請求過多,記憶體不足)
接下來的通過一個案例對hystrix的使用進行說明,案例完成的功能:Spring Cloud大型企業分散式微服務雲架構原始碼請加一七九一七四三三八零
服務消費者根據Id呼叫服務提供者的介面,獲取User表單的對應的記錄,若請求超時則返回id為-1的User記錄
一、基於Ribbon
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
<mybatis-spring-boot.version>1.2.0</mybatis-spring-boot.version>
<mysql-connector.version>5.1.39</mysql-connector.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
<version>1.3.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
<version>1.3.5.RELEASE</version>
</dependency>
</dependencies>
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2、application.yml
server:
port: 8089
spring:
application:
name: customer-user
eureka:
client:
serviceUrl:
defaultZone: http://user:zj123@localhost:8761/eureka
instance:
prefer-ip-address: true
instance-id: ${spring.application.name}:${spring.cloud.client.ipAddress}:${spring.application.instance_id:${server.port}}
provider-user:
ribbon:
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
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3、Controller呼叫類
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.zhuojing.bean.User;
@RestController
public class UserController {
@Autowired
private RestTemplate restTemplate;
@GetMapping(value="/simple/{id}",produces=MediaType.APPLICATION_JSON_VALUE+";charset=utf-8")
@HystrixCommand(fallbackMethod = "findByIdFallback")
public User findUserById(@PathVariable Long id){
//服務提供者地址 PROVIDER-USER
return this.restTemplate.getForObject("http://PROVIDER-USER/simple/"+id, User.class);
}
/**
* 斷路器模式,當請求的消費者provider-user超時的情況下,就會直接呼叫此方法,此方法的引數和返回型別必須和findUserById方法一致,請求超時時間為1秒
* @param id
* @return
*/
public User findByIdFallback(Long id){
User user = new User();
user.setId(0L);
return user;
}
}
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hystrix的預設的超時時間為1秒,若自定hystrix超時時間有一下兩種方式
a、@HystrixCommand註解配置
@HystrixCommand(fallbackMethod = "findByIdFallback",commandProperties = {
@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")
})
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b、在application.yml配置
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 5000
4、啟動類
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class AppCusRibbonPropertiesTest {
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(AppCusRibbonPropertiesTest.class, args);
}
}
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二、dashboard的使用
1、pom.xml
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
<version>1.3.5.RELEASE</version>
</dependency>
</dependencies>
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2、application.yml
server: port: 8030
3、啟動類
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
@EnableHystrixDashboard
@SpringBootApplication
public class DashboardApplication {
public static void main(String[] args) {
SpringApplication.run(DashboardApplication.class, args);
}
}
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啟動後訪問:http:/ /localhost:8030/hystrix 進入首頁,在位址列上輸入http:/ /localhost:8089/hystrix.stream(hystrix.stream)進行監控,在使用了hystrix的服務呼叫後才有資料。
三、Turbine的使用,Turbine是對微服務叢集的監聽
1、pom.xml
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-turbine</artifactId>
<version>1.3.5.RELEASE</version>
</dependency>
</dependencies>
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2、application.yml
server:
port: 8031
spring:
application:
name: microservice-hystrix-turbine
eureka:
client:
serviceUrl:
defaultZone: http://user:zj123@localhost:8761/eureka
instance:
prefer-ip-address: true
turbine:
aggregator:
clusterConfig: default #預設defualt,只有一個服務時候可以寫服務名稱的大寫CUSTOMER-USER
appConfig: customer-user
clusterNameExpression: "'default'"
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3、啟動類
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.turbine.EnableTurbine;
@EnableTurbine
@SpringBootApplication
public class TurbineApplication {
public static void main(String[] args) {
SpringApplication.run(TurbineApplication.class, args);
}
}
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hystrix 主頁面中將localhost:8031/turbine.stream?cluster=CUSTOMER-USER填入,便可進行資料的影象化。