spring_cloud_eureka实践

创建eureka-server

1.官网生成

https://start.spring.io/

添加依赖 eureka-server

2.使用idea的spring initializr

添加依赖eureka-server

生成后的pom.xml为

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>eureka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eureka</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
        <spring-cloud.version>Hoxton.SR9</spring-cloud.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>com.example.eureka.EurekaApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

添加@EnableEurekaServer

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@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

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

}

这时启动，发现会一直报错

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 [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_UNKNOWN/192.168.1.106: registering service...
2022-06-06 19:09:50.806  INFO 3394 --- [nfoReplicator-0] c.n.d.s.t.d.RedirectingEurekaHttpClient  : Request execution error. endpoint=DefaultEndpoint{ serviceUrl='http://localhost:8761/eureka/}, exception=java.net.ConnectException: Connection refused (Connection refused) stacktrace=com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused (Connection refused)

访问http://localhost:8080/是可以看到eureka-server的页面的。

这是因为默认配置是使用8761端口，这个服务也向eureka-server注册。

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server:
  port: 8761

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

Eureka instance的配置对应EurekaInstanceConfigBean

eureka client的配置对应EurekaClientConfigBean

registerWithEureka 默认为ture，意思是不注册到eureka

fetchRegistry 默认为ture,意思是不获取服务注册表

再启动后，不会报错，访问页面，发现Instances currently registered with Eureka 什么都没有。

创建eureka-client

同server创建方式，不添加server了，添加client和spring web

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>service-a</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>service-a</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
        <spring-cloud.version>Hoxton.SR9</spring-cloud.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>com.example.service_a.ServiceAApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>
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# 应用名称
spring:
  application:
    name: service-a

启动后，访问http://localhost:8761/，发现 service-a的服务实例。

添加测试controller

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# 应用名称
spring:
  application:
    name: service-a

server:
  port: 8762

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
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@RestController
public class TestController {

    @Value("${server.port}")
    String port;

    @RequestMapping("/test")
    public String test() {
        return "i am from port:" + port;
    }

}

访问http://localhost:8762/test

使用密码访问eureka

Eureka-server添加依赖

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<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
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@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
	@Override
	protected void configure(HttpSecurity http) throws Exception {
		// 关闭csrf
//		http.csrf().disable(); 
		/*
		 * 默认情况下添加SpringSecurity依赖的应用每个请求都需要添加CSRF token才能访问，Eureka客户端注册时并不会添加，所以需要配置/eureka/**路径不需要CSRF token。
		 */
		http.csrf().ignoringAntMatchers("/eureka/**");
		// 开启认证支持HttpBasic
		http.authorizeRequests().anyRequest().authenticated().and().httpBasic(); 
	}
}
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# 应用名称
spring:
  application:
    name: eureka

  security:
    user:
      name: root
      password: root

server:
  port: 8761

eureka:
  instance:
    hostname: localhost
  client:
    #设置服务注册中心的URL
    service-url:
      defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@${eureka.instance.hostname}:${server.port}/eureka/

这时访问http://localhost:8761/，需要用户名密码

高可用，2个节点

创建application-8762.yml、application-8763.yml

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# 应用名称
spring:
  application:
    name: eureka

  security:
    user:
      name: root
      password: root

server:
  port: 8762

eureka:
  instance:
    hostname: localhost
  client:
    #设置服务注册中心的URL
    service-url:
      defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@${eureka.instance.hostname}:8763/eureka/
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# 应用名称
spring:
  application:
    name: eureka

  security:
    user:
      name: root
      password: root

server:
  port: 8763

eureka:
  instance:
    hostname: localhost
  client:
    #设置服务注册中心的URL
    service-url:
      defaultZone: http://${spring.security.user.name}:${spring.security.user.password}@${eureka.instance.hostname}:8762/eureka/

互相注册，8762写8763的地址，8763写8762的地址。

在idea中运行配置中，添加修改选项 vm选项， 填入 -Dspring.profiles.active=8763

修改选项 选择允许多个实例。

访问http://localhost:8762/ http://localhost:8763/

发现有对方的实例。

高可用，3节点

创建application-8764.yml、application-8765.yml、application-8766.yml

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# 应用名称
spring:
  application:
    name: eureka

  security:
    user:
      name: root
      password: root

server:
  port: 8764

eureka:
  instance:
    hostname: localhost
  server:
    # 设置 eureka server同步失败的等待时间 默认 5分 , 在这期间，它不向客户端提供服务注册信息
    wait-time-in-ms-when-sync-empty: 0
  client:
    #设置服务注册中心的URL
    service-url:
      defaultZone: "http://root:root@${eureka.instance.hostname}:8764/eureka/,\
      http://root:root@${eureka.instance.hostname}:8765/eureka/,\
      http://root:root@${eureka.instance.hostname}:8766/eureka/"

访问 http://localhost:8764/ http://localhost:8765/ http://localhost:8766/

删除无效服务

1.查看spring_cloud_eureka的管理页面

http://用户名:密码@ip:port

2.删除服务节点

Request Method = DELETE
http://用户名:密码@ip:port/eureka/apps/服务名/注册名

上线与下线

1.强制下线

可以通过调用stateUpdate接口，更改实例的状态为OUT_OF_SERVICE 。

调用接口：/eureka/apps/appID/instanceID/status?value=OUT_OF_SERVICE

调用方式：PUT

2.手动上线

请求接口：/eureka/apps/appID/instanceID/status?value=UP

调用方式：PUT

spring_cloud
#spring_cloud #eureka
spring_cloud_eureka实践
http://hanqichuan.com/2022/06/06/spring_cloud/spring_cloud_eureka实践/
作者
韩启川
发布于
2022年6月6日
许可协议