Spring Cloud基于Eureka的微服务集群实现 - theseus - ITeye博客

安宇雨 - 随手采集
2019-04-22 11:15:41
随手采集
0000-未整理-等待研究

在Spring Cloud中集成了Eureka，因此可以在Spring Boot项目中使用Eureka的分布式服务，在本例中我们模拟Eureka的伪分布式的使用，端口分别为8761(默认),8762,8763，同时也需要修改host文件，指定为：

127.0.0.1 peer1

127.0.0.1 peer2

127.0.0.1 peer3

1、在Spring Cloud中启用Eureka，需在pom文件中加入以下依赖

Xml代码 "收藏这段代码")

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

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

</dependency>
<dependency>

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

</dependency>

2、接下来需要修改项目的配置文件，因模拟三个节点，也就需要三个配置文件，其中只是端口号、hostname的指定有所不同，application-s1.yml具体配置如下：

Java代码 "收藏这段代码")

server:
port: 8761
spring:
application:
name: EurekaServer
eureka:
instance:
hostname: peer1 #对应的hostname
client:
service-url:
defaultZone: #三个服务节点互联
http://peer1:8761/eureka/,http://peer2:8762/eureka/,http://peer3:8763/eureka/

server:
port: 8761
spring:
application:

name: EurekaServer

eureka:
instance:

hostname: peer1 #对应的hostname

client:

service-url:
  defaultZone: #三个服务节点互联
    http://peer1:8761/eureka/,http://peer2:8762/eureka/,http://peer3:8763/eureka/

application-s2.yml,application-s3.yml中修改对应端口与hostname即可

3、mani函数中加入Eureka服务注解

Java代码 "收藏这段代码")

@SpringBootApplication
@EnableEurekaServer
publicclass EurekaServerApp {
publicstaticvoid main(String[] args) {
SpringApplication.run(EurekaServerApp.class, args);
}
}

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApp {

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

}

4、使用maven打包，生成可运行的jar文件，执行以下命令

spring-cloud>java -jar eureka-server\target\eureka-server-0.0.1-SNAPSHOT.jar --spring.profiles.active=s1

spring-cloud>java -jar eureka-server\target\eureka-server-0.0.1-SNAPSHOT.jar --spring.profiles.active=s2

spring-cloud>java -jar eureka-server\target\eureka-server-0.0.1-SNAPSHOT.jar --spring.profiles.active=s3

启动时会报 Connect to peer3:8763 timed out之类的异常，待服务全启动后控制台窗口出现2017-04-12 16:46:14.991 INFO 13132 --- [nio-8761-exec-6] c.n.e.registry.AbstractInstanceRegistry : Registered instance EUREKASERVER/..*.144:EurekaServer:8
763 with status UP (replication=true)，说明服务已启动成功，打开http://localhost:8761/，可以看到集群运行正常

注：在配置文件中如果不使用域名的方式，而指定localhost或者ip(127.0.0.1/外网ip)，服务能够正常启动，但分片服务总显示在unavailable-replicas中，因此在host中指定了相应的域名做服务区分

5、添加对外服务接口，新建一个controller，并打印出当前调用服务的信息

Java代码 "收藏这段代码")

@RestController
publicclass AppServiceController {
privatefinal Logger logger = LoggerFactory.getLogger(getClass());
@Autowired
private DiscoveryClient client;
@SuppressWarnings("deprecation")
@RequestMapping("/hello/{user}")
public String hello(@PathVariable("user") String user) {
ServiceInstance instance = client.getLocalServiceInstance();
logger.info("/add, host:" + instance.getHost() + ", port: " + instance.getPort() + ", service_id:"
+ instance.getServiceId() + ", user:" + user);
return"Hello " + user;
}
}

@RestController
public class AppServiceController {

private final Logger logger = LoggerFactory.getLogger(getClass());

@Autowired
private DiscoveryClient client;

@SuppressWarnings("deprecation")
@RequestMapping("/hello/{user}")
public String hello(@PathVariable("user") String user) {
    ServiceInstance instance = client.getLocalServiceInstance();
    logger.info("/add, host:" + instance.getHost() + ", port: " + instance.getPort() + ", service_id:"
            \+ instance.getServiceId() + ", user:" + user);
    return "Hello " + user;
}

}

6、新建客户端调用工程，在工程中访问Eureka集群提供的rest服务，该工程是一个普通的Spring Boot项目，pom中添加以下依赖

Xml代码 "收藏这段代码")

<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>

<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>

7、配置文件中将该工程注册属性设置为false，不在Eureka集群中注册

Java代码 "收藏这段代码")

spring:
application:
name: eureka-client
eureka:
client:
register-with-eureka: false
server:
name: eurekaServer

spring:
application:

name: eureka-client

eureka:
client:

register-with-eureka: false

server:

name: eurekaServer

8、客户端的主类中通过服务名访问Eureka集群，默认负载均衡策略为轮询

Java代码 "收藏这段代码")

@SpringBootApplication
@EnableDiscoveryClient
@RestController
publicclass EurekaClientApp {
@Bean
@LoadBalanced
RestTemplate restTemplate() {
returnnew RestTemplate();
}
@Value("${eureka.server.name}")
private String eurekaServer;
@Autowired
RestTemplate restTemplate;
@RequestMapping(value = "/{user}")
public String hello(@PathVariable("user") String user) {
return restTemplate.getForEntity("http://" +eurekaServer +"/hello/"+ user, String.class).getBody();
}
publicstaticvoid main(String[] args) {
SpringApplication.run(EurekaClientApp.class, args);
}
}

@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class EurekaClientApp {


@Bean
@LoadBalanced
RestTemplate restTemplate() {
    return new RestTemplate();
}

@Value("${eureka.server.name}")
private String eurekaServer;

@Autowired
RestTemplate restTemplate;

@RequestMapping(value = "/{user}")
public String hello(@PathVariable("user") String user) {
    return restTemplate.getForEntity("http://" +eurekaServer +"/hello/"+ user, String.class).getBody();
}

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

}

9、访问http://localhost:8080/tom，页面打印 Hello tom，可以变换参数，在服务端显示访问的日志信息

2017-04-12 18:12:31.888 INFO 13088 --- [nio-8762-exec-3] org.eureka.server.AppServiceController : /add, host:peer2, port: 8762, service_id:EurekaServer, user:tom

2017-04-12 18:13:03.310 INFO 6448 --- [nio-8763-exec-2] org.eureka.server.AppServiceController :

/add, host:peer3, port: 8763, service_id:EurekaServer, user:jack

2017-04-12 18:13:24.342 INFO 12992 --- [nio-8761-exec-6] org.eureka.server.AppServiceController : /add, host:peer1, port: 8761, service_id:EurekaServer, user:anny

访问三次，可以看到服务端分别被访问一次，使用了轮询策略

项目代码地址：https://github.com/hjguang/spring-cloud

该项目中包含其他工程，可以使用以下命令只install Eureka项目

spring-cloud>mvn install -pl eureka-server,eureka-client -DskipTests=true

Original url: Access
Created at: 2019-04-22 11:15:41
Category: default
Tags: none

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