Spring Cloud Ribbon

• 客戶端負(fù)載均衡組件Ribbon 負(fù)載均衡就是當(dāng)client端發(fā)送請(qǐng)求得時(shí)候會(huì)均衡得分發(fā)到每個(gè)server端

創(chuàng)建spring-cloud-02-ribbon-eureka 就是個(gè)服務(wù)端 參考前面得copy過來的

創(chuàng)建spring-cloud-02-ribbon-client1 項(xiàng)目

• 引入pom.xml

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

• UserController

@RestController
public class UserController {


    @RequestMapping(value = "/getUser", method = {RequestMethod.GET})
    public User getUser(@RequestParam("id") String id) {
        System.err.println("client1 GET-------------" + id);
        return new User(id, "20", "張三");
    }
}

• application.properties

spring.application.name=client-service
server.port=1003
server.context-path=/
eureka.client.service-url.defaultZone=http://eureka1:8003/eureka/
spring.output.ansi.enabled=always

• copy client1項(xiàng)目一份

創(chuàng)建 spring-cloud-02-ribbon-request

• 引入pom.xml

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>

• application.properties

spring.application.name=request-service
server.context-path=/
server.port=1005
eureka.client.service-url.defaultZone=http://eureka1:8003/eureka/
spring.output.ansi.enabled=always

• 啟動(dòng)所有 request訪問http://localhost:1005/get 當(dāng)請(qǐng)求得次數(shù)一樣時(shí)燥爷，會(huì)發(fā)現(xiàn)分別在client1和client2端會(huì)打印出響應(yīng)得次數(shù)秒梳，每個(gè)都打印出一半
• 這就是負(fù)載均衡 Ribbon

在這里在介紹下retry重試機(jī)制

spring-cloud-02-ribbon-retry

• pom.xml

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
</dependency>

• application.properties配置

spring.application.name=retry-service
server.context-path=/
server.port=1006
eureka.client.service-url.defaultZone=http://eureka1:8003/eureka/
#啟動(dòng)重試機(jī)制
spring.cloud.loadbalancer.retry.enabled=true 
##斷路器
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=14000
##連接超時(shí)時(shí)間
#client-service.ribbon.ConnectTimeout=1000
##處理超時(shí)時(shí)間
#client-service.ribbon.ReadTimeout=1000

req.fact.connect-timeout=1000 
req.fact.connection-request-timeout=1000
req.fact.read-timeout=3000
#是否對(duì)所有請(qǐng)求都進(jìn)行重試
client-service.ribbon.OKToRetryOnAllOperations=true
#重試切換實(shí)例得次數(shù)
client-service.ribbon.MaxAutoRetriesNextServer=1
#重試切次數(shù)
client-service.ribbon.MaxAutoRetries=5

• 注意：

client-service.ribbon.ConnectTimeout=1000
client-service.ribbon.ReadTimeout=1000
這樣配置沒起作用  建議使用RestTemplate原始配置
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds：斷路器得超時(shí)時(shí)間需要大于ribbon得超時(shí)時(shí)間，不然不會(huì)發(fā)生重試。

• RetryApplication類

@EnableCircuitBreaker //開啟斷路器
@EnableRetry    //啟動(dòng)Retry框架重試機(jī)制
@EnableDiscoveryClient //我是服務(wù) 注冊(cè)到服務(wù)中心上
@SpringBootApplication
public class RetryApplication {


    @Bean
    @ConfigurationProperties(prefix = "req.fact")
    public HttpComponentsClientHttpRequestFactory httpComponentsClientHttpRequestFactory(){
        return new HttpComponentsClientHttpRequestFactory();
    }

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate(httpComponentsClientHttpRequestFactory());
    }
    public static void main(String[] args) {
        SpringApplication.run(RetryApplication.class, args);
    }
}

• IndexController類

@RestController
public class IndexController {

    @Autowired
    RestTemplate restTemplate;

    @RequestMapping(value = "/retry", method = {RequestMethod.GET})
    @HystrixCommand(fallbackMethod = "retryFailback")
    public String retry(){
        ResponseEntity<String> response = restTemplate.getForEntity("http://client-service/retry", String.class);
        System.err.println("body:" + response.getBody());
        return "----- retry ok -----";
    }

    public String retryFailback(){
        System.err.println("-----啟動(dòng)降級(jí)策略----");
        return "-----啟動(dòng)降級(jí)策略----";
    }
}

• 在spring-cloud-02-ribbon-client1項(xiàng)目得Controller中添加

 @RequestMapping(value = "/retry", method = {RequestMethod.GET})
    public String retry() {
        System.err.println("client1  1 call-------------");
        try {
            Thread.sleep(4000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "client 1";
    }

• 在spring-cloud-02-ribbon-client2項(xiàng)目得Controller中添加

 @RequestMapping(value = "/retry", method = {RequestMethod.GET})
    public String retry() {
        System.err.println("client1  2 call-------------");
        return "client 2";
    }

• 在啟動(dòng)http://localhost:1006/retry時(shí)枷踏，通過Ribbon負(fù)載均衡會(huì)訪問client1或者client2項(xiàng)目得retry方法，當(dāng)訪問到client1得retry方法時(shí)，配置得讀取超時(shí)時(shí)間為3ms斥赋，重試次數(shù)為5次，retry方法睡眠為4ms绢慢，就是每次訪問retry方法時(shí)重試灿渴，當(dāng)重試次數(shù)6次后，會(huì)采用降級(jí)策略胰舆，因?yàn)槿蹟嗥髋渲玫脼?4ms骚露，超過熔斷器得時(shí)間就會(huì)采用降級(jí)策略。
• GitHub地址
• hystrix 先入個(gè)門