SpringCloud:(一)服务注册与发现

最近跟着方志明老师学习SpringCloud，博客地址如下：

https://blog.csdn.net/forezp/article/details/81040925

自己也跟着撸了一遍，纸上得来终觉浅，绝知此事要躬行，以下是自己撸的时候的总结&注意事项：

（一）创建maven项目

打开idea

File—new—project—maven

创建maven项目

Pom文件导入相应服务的依赖

<?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>springcloud</groupId>
    <artifactId>clouddemo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <name>clouddemo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/>
    </parent>

    <modules>
        <module>eureka-server</module>
        <module>service-hi</module>
    </modules>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <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>${spring-cloud.version}</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>

</project>
注：

version版本升级到了2.1.1，不然会报

java.lang.AbstractMethodError: null at org.springframework.core.OrderComparator.findOrder等错误

<version>2.1.1.RELEASE</version>
（二）创建2个model工程作为服务注册中心：Eureka server & Eureka client

2.1Eureka server

2.1.1

父项目—new—module—spring initializr—cloud discovery—eureka server

继承父pom文件，引入spring—cloud—starter—Netflix—eureka—server的依赖

<?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>
    <parent>
        <groupId>springcloud</groupId>
        <artifactId>clouddemo</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.springcloud</groupId>
    <artifactId>eureka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>eureka-server</name>
    <description>Demo project for Spring cloud</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

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

    </dependencies>

</project>
2.1.2
启动一个服务注册中心，需要一个注解@EnableEurekaServer，这个注解需要在springboot工程的启动application类上加：

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaServerApplication.class, args);
    }

}

2.1.3配置文件appication.yml，指定server：

server:
  port: 8761

eureka:
  instance:
    hostname: localhost
  client:
    #通过eureka.client.registerWithEureka：false和fetchRegistry
    #false来表明自己是一个eureka server
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

spring:
  application:
    name: eurka-server
完成以后，启动服务，打开启动工程,打开浏览器访问：
http://localhost:8761页面，显示没有服务--没有注册服务当然不可能有服务被发现了。。。。

2.2 Eureka client--server-hi

步骤同2.1，创建module项目（服务提供者）

pom文件

<?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>
    <parent>
        <groupId>springcloud</groupId>
        <artifactId>clouddemo</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <groupId>com.eureka.client</groupId>
    <artifactId>service-hi</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>service-hi</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</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-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>
2.2.1启动类添加注解，注解@EnableEurekaClient 表明自己是一个eurekaclient

@SpringBootApplication
@EnableEurekaClient
@RestController
public class ServiceHiApplication {

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

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

@RequestMapping("/hi")
public String home(@RequestParam(value = "name", defaultValue = "clouddemo") String name) {
return "hi " + name + " ,i am from port:" + port;
}

}

2.2.2在配置文件中注明自己的服务注册中心的地址

server:
  port: 8762

spring:
  application:
    name: service-hi

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3.1启动eureka-server服务，打开 http://localhost:8761

3.2启动service-hi服务，访问service-hi页面，http://localhost:8762/hi?name=clouddemo

3.3刷新eureka-server访问的页面
服务已经注册在服务中了，服务名为SERVICE-HI ,端口为7862