Spring Cloud 入门教程(一): 服务注册

╰半橙微兮° 2021-09-27 11:32 254阅读 0赞

创建一个Maven工程，New-Other-Maven-Maven Probject

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点击Next,红色框里的选上

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点击Next

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点击Finsh就完成了一个Maven Probject的创建。

（1）接下来配置Maven工程下的pom文件

<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.cn.study</groupId>
      <artifactId>eureka.server</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <packaging>jar</packaging>
      
      <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.3.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            
            <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>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-config</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Dalston.RC1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
        <repositories>
            <repository>
                <id>spring-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
        </repositories>
    </project>

（2）创建一个服务类EurekaServerApplication，需要一个注解@EnableEurekaServer加在springboot工程的启动类上

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（3）在resource目录下创建appication.yml，也可以创建appication.properites。2种方式为什么选用yml？是因为yml在很多配置的情况下更好的修改，它的存储试以key/value方式。properites的文件如果配置内容过多，没有放在一起的话，修改可能会忘掉，会造成一些不必要的麻烦。当然的写2个名称相同的文件同时存在也是可以的，只不过有优先级问题。properites文件优先级比yml的更高，最好是不要同时使用2个名称相同的文件。

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以下2种写法都一样：

fetch-registry和fetchRegistry一样

当fetch-registry: true时报错如下图，报错原因是：在默认设置下，eureka服务注册中心也会将自己作为客户端来尝试注册它自己，所以我们需要禁用它的客户端注册行为

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解决方法：

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（4）启动服务

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（5）创建一个Maven工程Eureka Client,pom文件内容如下：

<?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>
        <groupId>com.cn.study</groupId>
        <artifactId>eureka.client</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>springcloud.helloworld.eureka.client</name>
        <packaging>jar</packaging>
        <description>Demo Spring Boot Client</description>
    
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.5.3.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-eureka</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>
            </dependency>
        </dependencies>
    
        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Dalston.RC1</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
        <repositories>
            <repository>
                <id>spring-milestones</id>
                <name>Spring Milestones</name>
                <url>https://repo.spring.io/milestone</url>
                <snapshots>
                    <enabled>false</enabled>
                </snapshots>
            </repository>
        </repositories>
    
    
    </project>
    
    pom.xml

（6）创建类ServiceApplication

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（7）配置eureka.client的文件appication.yml

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（8）启动ServiceApplication，并访问

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（9）刷新Eureka，就能看到有服务注册上去了

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（9）Eureka的自我保护机制

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保护模式主要用于一组客户端和Eureka Server之间存在网络分区场景下的保护。一旦进入保护模式，Eureka Server将会尝试保护其服务注册表中的信息，不再删除服务注册表中的数据（也就是不会注销任何微服务）。

详见：[https://github.com/Netflix/eureka/wiki/Understanding-Eureka-Peer-to-Peer-Communication][https_github.com_Netflix_eureka_wiki_Understanding-Eureka-Peer-to-Peer-Communication]

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[https_github.com_Netflix_eureka_wiki_Understanding-Eureka-Peer-to-Peer-Communication]: https://github.com/Netflix/eureka/wiki/Understanding-Eureka-Peer-to-Peer-Communication