Links to the original text: https://cloud.tencent.com/developer/article/1406881

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.pricemonitor</groupId>
<artifactId>springcloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<name>springcloud</name>

<! - Submodule - >
<modules>
<module>eureka</module>
</modules>

<! - Parent: Spring Boot ->
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.3.RELEASE</version>
</parent>

<! - Parameters - >
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>

<! - Spring Cloud Version Sequence Configuration ->
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Finchley.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>

<dependencies>
<! - Spring Boot Actuator Component -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!-Spring Cloud Foundation-
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter</artifactId>
</dependency>
<!-Spring Cloud Service Registration Component-
<dependency>
<groupId>org.springframework.cloud</groupId>
<! - The dependencies here are dedicated after SpringBoot 2.0. If you use SpringBoot version less than 2.0, use spring-cloud-starter-eureka-server ->.
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<! - Spring Boot Web Component -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<! --- Spring Book Test Component --> ___________
<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>

</project>

Create registry Eureka sub-module

Introduction to Eureka

Spring Cloud encapsulates the Eureka module developed by Netflix to implement service registration and discovery. Eureka uses the C-S design architecture. Eureka Server serves as a service registration function, and it is a service registry. Other micro services in the system use Eureka clients to connect to Eureka Server and maintain heartbeat connections. In this way, the maintainer of the system can monitor the normal operation of each micro-service through Eureka Server. Some other modules of Spring Cloud, such as Zuul, can use Eureka Server to discover other micro services in the system and execute related logic.

Eureka consists of two components: the Eureka server and the Eureka client. The Eureka server serves as a service registration server. The Eureka client is a java client that simplifies interaction with the server and acts as polling load balancing It also provides service failover support. Netflix uses another client in its production environment, which provides weighted load balancing based on traffic, resource utilization, and error status.

The figure above briefly describes the basic architecture of Eureka, which consists of three roles:

1,Eureka Server

• Providing service registration and discovery

2,Service Provider

• service provider
• Register your own services in Eureka so that service consumers can find them

3,Service Consumer

• Service consumer
• Get a list of registered services from Eureka so that services can be consumed

Editing sub-module Eureka's pom.xml

Next, we create a Spring Cloud registration center Eureka in the sub-module Eureka.

Code emphasis:

• Inherited the parent pom.xml
• As you can see, there is no new dependency introduced here, so how to introduce Eureka component dependency? Back to the main pom.xml above, you will find that I introduced spring-cloud-starter-netflix-eureka-server in it, because in most of the later modules, we will use Eureka-server, so we put it in the main. POM for sharing with other sub-modules
• Submodules can be packaged to run jar: <packaging>jar</packaging>

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
<span class="token operator">&lt;</span>artifactId<span class="token operator">&gt;</span>eureka<span class="token operator">&lt;</span><span class="token operator">/</span>artifactId<span class="token operator">&gt;</span>
<span class="token operator">&lt;</span>version<span class="token operator">&gt;</span><span class="token number">0.0</span><span class="token punctuation">.</span><span class="token number">1</span><span class="token operator">-</span>SNAPSHOT<span class="token operator">&lt;</span><span class="token operator">/</span>version<span class="token operator">&gt;</span>
<span class="token operator">&lt;</span>name<span class="token operator">&gt;</span>eureka<span class="token operator">&lt;</span><span class="token operator">/</span>name<span class="token operator">&gt;</span>
<span class="token operator">&lt;</span>packaging<span class="token operator">&gt;</span>jar<span class="token operator">&lt;</span><span class="token operator">/</span>packaging<span class="token operator">&gt;</span>
<span class="token operator">&lt;</span>description<span class="token operator">&gt;</span>Demo project <span class="token keyword">for</span> Spring Boot<span class="token operator">&lt;</span><span class="token operator">/</span>description<span class="token operator">&gt;</span>

<span class="token operator">&lt;</span><span class="token operator">!</span><span class="token operator">--</span>Dependence on Parent Engineering<span class="token operator">--</span><span class="token operator">&gt;</span>
<span class="token operator">&lt;</span>parent<span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span>groupId<span class="token operator">&gt;</span>com<span class="token punctuation">.</span>pricemonitor<span class="token operator">&lt;</span><span class="token operator">/</span>groupId<span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span>artifactId<span class="token operator">&gt;</span>springcloud<span class="token operator">&lt;</span><span class="token operator">/</span>artifactId<span class="token operator">&gt;</span>
    <span class="token operator">&lt;</span>version<span class="token operator">&gt;</span><span class="token number">0.0</span><span class="token punctuation">.</span><span class="token number">1</span><span class="token operator">-</span>SNAPSHOT<span class="token operator">&lt;</span><span class="token operator">/</span>version<span class="token operator">&gt;</span>
<span class="token operator">&lt;</span><span class="token operator">/</span>parent<span class="token operator">&gt;</span>


<span class="token operator">&lt;</span>dependencies<span class="token operator">&gt;</span>

<span class="token operator">&lt;</span><span class="token operator">/</span>dependencies<span class="token operator">&gt;</span>

</project>

Add the @EnableEurekaServer annotation to the startup code

EurekaApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

<span class="token keyword">public</span> <span class="token keyword">static</span> <span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span>String<span class="token punctuation">[</span><span class="token punctuation">]</span> args<span class="token punctuation">)</span> <span class="token punctuation">{</span>
    SpringApplication<span class="token punctuation">.</span><span class="token function">run</span><span class="token punctuation">(</span>EurekaApplication<span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">,</span> args<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

If you find that @Enable Eureka Server cannot be introduced, check that your Spring Cloud version is compatible with Spring Book version:

springboot cannot introduce @enableeurekaserver and Spring Cloud matching with Spring Boot versions:

https://blog.csdn.net/zhang53141/article/details/83091032

configuration file

The default generated configuration file is application.properties, which can also be written in application.yml format. The configuration is as follows:

# Port number
server:
  port: 8761
# Service registration related configuration
eureka:
  # Service instance hostname
  instance:
    hostname: localhost
  # Service Provider Configuration
  client:
    # No registration (configuration when the service registry is single rather than highly available)
    registerWithEureka: false
    # Not getting registration information (configuration when the service registry is single rather than highly available)
    fetchRegistry: false
    # Service Registry Address
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

Be careful:

• RegiserWithEureka: false indicates that the current service registry does not register in other service registries.
• fetchRegistry: false indicates that the current service registry does not obtain registration information from other service registries.
• The above two configurations are configurable only when the service registry is a single point configuration, because these two values are necessarily false in a single point.

Function

You can see the following page, which hasn't found any services yet. It's just a lone eureka-server.

In the next tutorial, we will create a service provider and register in Eureka.

The corresponding engineering code for this tutorial

https://github.com/qqxx6661/springcloud_for_noob/tree/master/01-eureka