1.Eureka

分布式系统中，当B的数量越来越多的时候，A只需要从注册中心获取B注册的服务，而不需要直接从B中获取服务，答案显而易见。

application.yml:

eureka:
  client:
    service-url:
      defaultZone: http://114.55.229.69:8761/eureka
    register-with-eureka: false #自身不在eureka上注册
  server:
    enable-self-preservation: false #关闭自我保护（客户端跟服务端长时间连不上，eureka控制台上有红色警告，开发环境设置成false，线上为true）
  instance:
    hostname: localhost #跳转地址
spring:
  application:
    name: eureka-server
server:
  port: 8761

EurekaApplication:

package com.wangfajun;

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

@SpringBootApplication
@EnableEurekaServer //Eureka服务端
public class EurekaApplication {

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

Pom.xml:

<?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.wangfajun</groupId>
    <artifactId>fajun-server-eureka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>fajun-eureka-server</name>
    <description>Eureka Server</description>

    <parent>
        <groupId>com.wangfajun</groupId>
        <artifactId>fajun-store</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <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>
        </dependency>
    </dependencies>

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

</project>

 Tip：Eureka服务端高可用，生产上建议至少两台以上，相互注册即可

服务端：
机器：114.55.229.69,端口：8761机器
defaultZone: http://118.178.144.64:8762/eureka,http://114.55.88.126:8763/eureka
机器：118.178.144.64,端口:8762机器
defaultZone: http://114.55.229.69:8761/eureka,http://114.55.88.126:8763/eureka
机器：114.55.88.126,端口:8763机器
defaultZone: http://114.55.229.69:8761/eureka,http://118.178.144.64:8762/eureka

客户端：
http://114.55.229.69:8761/eureka,http://118.178.144.64:8762/eureka,http://114.55.88.126:8763/eureka