SpringCloud（四）eureka注册中心集群的使用

古城微笑少年丶 2022-01-09 11:11 287阅读 0赞

## 源码 ##

GitHub：[https://github.com/291685399/springcloud-learning/tree/master/springcloud-eureka03][https_github.com_291685399_springcloud-learning_tree_master_springcloud-eureka03]

## 目标 ##

**上一篇[SpringCloud（二）eureka注册中心的使用][SpringCloud_eureka]介绍如何使用eureka，但是在实际使用中，一般都是集群，下面介绍如何给eureka server搭建集群，同时client连接集群**

## eureka的使用 ##

*  新建一个父工程，命名为springcloud-eureka03

目录结构如下图：  
![在这里插入图片描述][20190622105600698.png]  
pom.xml：

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath/>
    </parent>
    
    <dependencies>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

*  新建模块，命名为eureka-server03\_1

目录结构如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70]  
pom.xml：

在启动器EurekaServer03\_1Application上添加注解用于开启eureka server

@SpringBootApplication
    @EnableEurekaServer
    public class EurekaServer03_1Application { 
        public static void main(String[] args) { 
            SpringApplication.run(EurekaServer03_1Application.class, args);
        }
    }

在application.properties：

**注意：**

1、这里的端口，eureka-server03\_1的端口是10000，后面新建的模块eureka-server03\_2端口为10001，所以它需要连接的eureka server地址为http://127.0.0.1:10001/eureka，当然eureka-server03\_2需要连接的eureka-server地址为http://127.0.0.1:10000/eureka，这样才能给eureka server形成一个集群  
2、需要将之前使用eureka配置中的eureka.client.register-with-eureka=false和eureka.client.fetch-registry=false注释

server.port=10000
    spring.application.name:eureka-server
    # 是否注册自己的信息到EurekaServer，默认是true
    #eureka.client.register-with-eureka=false
    # 是否拉取其它服务的信息，默认是true
    #eureka.client.fetch-registry=false
    # EurekaServer的地址，现在是自己的地址，如果是集群，需要加上其它Server的地址
    eureka.client.service-url.defaultZone:http://127.0.0.1:10001/eureka

*  新建模块，命名为eureka-server03\_2

目录结构如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 1]  
pom.xml：

在启动器EurekaServer03\_2Application上添加注解用于开启eureka server

@SpringBootApplication
    @EnableEurekaServer
    public class EurekaServer03_2Application { 
        public static void main(String[] args) { 
            SpringApplication.run(EurekaServer03_2Application.class, args);
        }
    }

在application.properties：

**注意：**

1、这里的端口，eureka-server03\_1的端口是10000，后面新建的模块eureka-server03\_2端口为10001，所以它需要连接的eureka server地址为http://127.0.0.1:10000/eureka，当然eureka-server03\_2需要连接的eureka-server地址为http://127.0.0.1:10000/eureka，这样才能给eureka server形成一个集群  
2、需要将之前使用eureka配置中的eureka.client.register-with-eureka=false和eureka.client.fetch-registry=false注释

*  新建模块，命名为eureka-provider03

目录结构如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 2]  
pom.xml：

<parent>
        <groupId>com.wyj</groupId>
        <artifactId>springcloud-eureka03</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
    </properties>
    
    <dependencies>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>
    
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

在启动器EurekaProvider03Application上添加注解用于开启eureka client

@SpringBootApplication
    @EnableDiscoveryClient
    public class EurekaProvider03Application{ 
        public static void main(String[] args) { 
            SpringApplication.run(EurekaProvider03Application.class, args);
        }
    }

ProviderController：

@Controller
    public class ProviderController { 
    
        @Autowired
        private UserService userService;
    
        @RequestMapping(value = "/findById/{id}")
        @ResponseBody
        public User findById(@PathVariable int id) { 
            User user = userService.findById(id);
            return user;
        }
    }

UserService：

public interface UserService { 
        public User findById(int id);
    }

UserServiceImpl：

@Service
    public class UserServiceImpl implements UserService { 
    
        @Autowired
        private UserRepository userRepository;
    
        @Override
        public User findById(int id) { 
            Optional<User> userOptional = userRepository.findById(id);
            User user = userOptional.get();
            return user;
        }
    }

UserRepository：

public interface UserRepository extends JpaRepository<User, Integer> { 
    }

User：

@Entity
    @Data
    public class User implements Serializable { 
    
        @Id
        @GeneratedValue
        private int id;
        private String name;
        private String sex;
        private int age;
        private String address;
        private String phone;
    }

application.properties：

**注意：**

这里eureka server的地址应该是多个，因为eureka server是集群

server.port=8081
    ### datasource ###
    spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springcloud-eureka01?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.username=root
    spring.datasource.password=root
    ### springdatajpa ###
    #打印出自动生产的SQL，方便调试的时候查看
    spring.jpa.show-sql=true
    #更新数据库表结构
    spring.jpa.hibernate.ddl-auto= update
    #对打印的sql进行格式化，方便查看
    spring.jpa.properties.hibernate.format_sql= true
    spring.jpa.properties.hibernate.use_sql_comments=true
    #指定生成表名的存储引擎为InneoDB
    spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
    # springcloud
    spring.application.name=eureka-provider
    # EurekaServer地址，因为EurekaServer不止一个，因此注册服务的时候，EurekaServer地址,多个地址以','隔开
    eureka.client.service-url.defaultZone=http://127.0.0.1:10000/eureka,http://127.0.0.1:10001/eureka
    # 当调用getHostname获取实例的hostname时，返回ip而不是host名称
    eureka.instance.prefer-ip-address=true
    eureka.instance.ip-address=127.0.0.1

*  新建模块，命名为eureka-consumer03

目录结构如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 3]  
pom.xml：

<parent>
        <groupId>com.wyj</groupId>
        <artifactId>springcloud-eureka03</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.SR1</spring-cloud.version>
    </properties>
    
    <dependencies>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>
    
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

在启动器EurekaConsumer03Application上添加注解用于开启eureka client

@SpringBootApplication
    @EnableDiscoveryClient
    public class EurekaConsumer03Application{ 
        public static void main(String[] args) { 
            SpringApplication.run(EurekaConsumer03Application.class, args);
        }
    }

ConsumerController：

@Controller
    public class ConsumerController{ 
    
        @Autowired
        private RestTemplate restTemplate;
    
        // Eureka客户端，可以获取到服务实例信息
        @Autowired
        private DiscoveryClient discoveryClient;
    
        @RequestMapping(value = "/findById/{id}")
        @ResponseBody
        public User findById(@PathVariable int id) { 
            // 根据服务名称，获取服务实例
            List<ServiceInstance> instances = discoveryClient.getInstances("eureka-provider");
            // 因为只有一个UserService,因此我们直接get(0)获取
            ServiceInstance instance = instances.get(0);
            String baseUrl = "http://" + instance.getHost() + ":" + instance.getPort();
            System.out.println("baseUrl=" + baseUrl);
            User user = restTemplate.getForObject(baseUrl + "/findById/" + id, User.class);
            return user;
        }
    }

RestConfig：

@Configuration
    public class RestConfig { 
    
        @Bean
        public RestTemplate restTemplate() { 
            return new RestTemplate();
        }
    }

User：

@Data
    public class User implements Serializable { 
    
        private int id;
        private String name;
        private String sex;
        private int age;
        private String address;
        private String phone;
    }

application.properties：

**注意：**

这里eureka server的地址应该是多个，因为eureka server是集群

server.port=8080
    # springcloud
    spring.application.name=eureka-consumer
    # EurekaServer地址，因为EurekaServer不止一个，因此注册服务的时候，EurekaServer地址,多个地址以','隔开
    eureka.client.service-url.defaultZone=http://127.0.0.1:10000/eureka,http://127.0.0.1:10001/eureka
    # 当调用getHostname获取实例的hostname时，返回ip而不是host名称
    eureka.instance.prefer-ip-address=true

## 测试使用 ##

分别启动eureka-server03\_1、eureka-server03\_2、eureka-provider03和eureka-consumer03

**注意：**  
两个server先启动的server会报错，如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 4]  
然后另外一台server启动后就不报错了，这是正确的，因为先启动的那台server不能找到另外一台形成集群，就报错了，当另外一台server启动时，找到了，就不报错了。

*  访问

浏览器访问http://127.0.0.1:8080/findById/1  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 5]

*  访问eureka  
    [http://127.0.0.1:10000/][http_127.0.0.1_10000] （这里访问的是端口号为10000的server）访问http://127.0.0.1:10001/也是一样的  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 6]  
    可以看到当前有eureka-consumer、eureka-provider两个实例和eureka-server形成的集群

[https_github.com_291685399_springcloud-learning_tree_master_springcloud-eureka03]: https://github.com/291685399/springcloud-learning/tree/master/springcloud-eureka03
[SpringCloud_eureka]: https://blog.csdn.net/qq_35620501/article/details/93234600
[20190622105600698.png]: /images/20220109/248cd2869ed04633bedc9dc0f16ff440.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70]: /images/20220109/292101b2666746a886fd57982be088b1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 1]: /images/20220109/de817c581512494b8308f124f1ac8a77.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 2]: /images/20220109/9cfe99eeb9b948939c6c6b12abefbacb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 3]: /images/20220109/bb5b469de55442b2b04ed675e2d8dbeb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 4]: /images/20220109/4dea590a846b46f08106fe8f489e9ef5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 5]: /images/20220109/ea7380f7bd32405192229d7931ea1356.png
[http_127.0.0.1_10000]: http://127.0.0.1:10000/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1NjIwNTAx_size_16_color_FFFFFF_t_70 6]: /images/20220109/3efeb3358d70414bada2931b6150d5d1.png