搭建SpringCloud思路

一、 先了解下SpringCloud微服务的设计理念和初衷。

• 业务分层更细致,对应的服务写对应的业务。服务之间解耦，一台工作某业务的服务挂了不影响其他服务。
• 分布式部署，多服务分摊压力。可伸缩扩展。
• 服务治理，提供了一套完整的服务治理解决方案，有活跃的社区，丰富的组件。
• 缺点：微服务过多，治理成本高，不利于维护系统。
• 缺点：分布式系统开发的成本高（容错，分布式事务等）对团队挑战大.

二、SpringCloud的一些组件

• 服务注册中心：nacos，eureka(功能单一)。
• 配置中心：nacos，Spring Cloud Config.
• 网关：gateway
• 断路器： Hystrix，sentinel
• 服务调用： Ribbon，Feign
• 链路追踪：SkyWalking

三、搭建步骤
首先用idea搭建一个Maven主工程，删除rsc，只保留pom.xml,主pom只控制cloud版本 和springBoot版本。

<?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.cloud</groupId>
    <artifactId>cloudDemo</artifactId>
    <packaging>pom</packaging>
    <version>0.0.1-SNAPSHOT</version>

    <name>cloudDemo</name>
    <description>cloudDemo</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.7.RELEASE</version>
    </parent>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring.cloud.alibaba.version>2.2.3.RELEASE</spring.cloud.alibaba.version>
        <spring.cloud.version>Hoxton.SR6</spring.cloud.version>
        <cloudDemo.version>0.0.1-SNAPSHOT</cloudDemo.version>
        <spring.boot.version>2.3.7.RELEASE</spring.boot.version>
        <nacos.version>2.2.3.RELEASE</nacos.version>
    </properties>

    <!--全局引入下载依赖地址，并不会引入依赖-->
    <dependencyManagement>
        <dependencies>
            <!--阿里巴巴下载仓库-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring.cloud.alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--springcloud下载仓库-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring.cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>


</project>

二。通过IDEA在 cloudDemo 下建立一个子模块cloud-commons，作为公用基础模块，所有服务需要用到的实体类，工具类，枚举，开源工具需要的引入的依赖都放入cloud-commons 的依赖。统一在cloud-commons管理公用依赖，如有个别服务需要特殊引用依赖，则放在自己的服务pom中。里面的resources文件内容删掉，不需要。
可以看到里面有ali的easyexcel， elasticsearch，nacos，openfeign，nacos-config
lombok。 然后每个自服务都引入 cloud-commons 包就能用到以上的依赖

<?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">
    <parent>
        <artifactId>cloudDemo</artifactId>
        <groupId>com.cloud</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-commons</artifactId>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <!--nacos client-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>${nacos.version}</version>
        </dependency>
            <!-- ES搜索引擎 -->

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

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.6.1</version>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.6.1</version>
        </dependency>

        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-client</artifactId>
            <version>7.6.1</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba.boot</groupId>
            <artifactId>nacos-config-spring-boot-starter</artifactId>
            <version>0.2.3</version>
        </dependency>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.2.5.RELEASE</version>
        </dependency>
        <!--(nacos统一配置中心管理依赖)-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2.2.3.RELEASE</version>
        </dependency>

        <!--sentinel 哨兵 依赖-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
            <version>2.2.3.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
        </dependency>

        <dependency>
            <groupId>io.github.openfeign</groupId>
            <artifactId>feign-okhttp</artifactId>
            <version>11.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>${spring.boot.version}</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>${apache.poi.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>${apache.poi.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-scratchpad</artifactId>
            <version>${apache.poi.version}</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>${easy.excel.version}</version>
        </dependency>
    </dependencies>


</project>

cloud-commons中的目录结构如下：

三、通过IDEA在 cloudDemo 下建立一个子模块 product，pom如下：
此时commons 中的依赖 product 都可用

<?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">
    <parent>
        <artifactId>cloudDemo</artifactId>
        <groupId>com.cloud</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>
    <packaging>jar</packaging>
    <groupId>com.example</groupId>
    <artifactId>product</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>product</name>
    <description>product</description>

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

    <dependencies>
        <!--  公共模块,实体类,工具类,公用模块 -->
        <dependency>
            <groupId>com.cloud</groupId>
            <artifactId>cloud-commons</artifactId>
            <version>${cloudDemo.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</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.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>${spring.boot.version}</version>
                <configuration>
                    <mainClass>com.example.product.ProductApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

来看下product的yml:

server:
  port: 8082
spring:
  profiles:
    active: dev
  application:
    name: product
  cloud:
    nacos:
      server-addr: localhost:8848
      discovery:
        server-addr:  ${spring.cloud.nacos.server-addr}
        namespace: ee751565-14dd-4654-8ad3-1d8c046189fd
      config:
        server-addr: ${spring.cloud.nacos.server-addr}
        namespace: ee751565-14dd-4654-8ad3-1d8c046189fd
        group: DEV_GROUP
        file-extension: yaml
        extension-configs:
          - data-id: product-dev.yml
            group: DEV_GROUP
            refresh: true
          - data-id: product-dev.yml
            group: DEFAULT_GROUP
            refresh: true
        enabled: true
        refresh-enabled: true
#    sentinel:
#      enabled: true
#      eager: true
#      transport:
#        dashboard: localhost:8718
#        port: 8718
#  aop:
#    #采用CGLIB作为作为动态代理，默认true  为了解决使用 JDK 动态代理可能导致的类型转化异常而默认使用 CGLIB (boot1.x版本默认是false)
#    proxy-target-class: true
#    #是否开启aop自动配置，默认为true
#    #意味着自动加上 @EnableAspectAutoProxy 注解
#    #该注解用于开启AOP相关注解得支持
#    auto: true

# 正确配置:
#nacos:
#  config:
#    server-addr: 127.0.0.1:8848
#    type: yaml
#    bootstrap:
#      enable: true
#  discovery:
#    server-addr: 127.0.0.1:8848

启动类上的注解：

package com.example.product;

import com.alibaba.nacos.spring.context.annotation.config.NacosPropertySource;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
//@NacosPropertySource(dataId = "product-dev.yml", groupId = "DEV_GROUP",autoRefreshed = true)
public class ProductApplication {

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

}

四、通过IDEA在 cloudDemo 下建立一个子模块 user，pom如下：
此时commons 中的依赖 user都可用

<?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.cloud</groupId>
    <artifactId>cloudDemo</artifactId>
    <packaging>pom</packaging>
    <version>0.0.1-SNAPSHOT</version>

    <modules>
        <module>cloud-commons</module>
        <module>user</module>
        <module>product</module>
        <module>cloud-gateway</module>
    </modules>
    <name>cloudDemo</name>
    <description>cloudDemo</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.7.RELEASE</version>
    </parent>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring.cloud.alibaba.version>2.2.3.RELEASE</spring.cloud.alibaba.version>
        <spring.cloud.version>Hoxton.SR6</spring.cloud.version>
        <cloudDemo.version>0.0.1-SNAPSHOT</cloudDemo.version>
        <spring.boot.version>2.3.7.RELEASE</spring.boot.version>
        <easy.excel.version>3.0.5</easy.excel.version>
        <apache.poi.version>4.1.2</apache.poi.version>
        <nacos.version>2.2.3.RELEASE</nacos.version>
    </properties>

    <!--全局引入下载依赖地址，并不会引入依赖-->
    <dependencyManagement>
        <dependencies>
            <!--阿里巴巴下载仓库-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring.cloud.alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--springcloud下载仓库-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring.cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>


</project>

来看下 user 的yml:

server:
  port: 8081
  servlet:
    context-path=/ems: /ems
spring:
  profiles:
    active: dev
  application:
    name: user
  elasticsearch:
    rest:
      username: elastic
      password: 123456
      uris: 127.0.0.1:9200
  cloud:
    nacos:
      server-addr: localhost:8848
      discovery:
        server-addr:  ${spring.cloud.nacos.server-addr}
        namespace: ee751565-14dd-4654-8ad3-1d8c046189fd
      config:
        server-addr: ${spring.cloud.nacos.server-addr}
        namespace: ee751565-14dd-4654-8ad3-1d8c046189fd
        group: DEV_GROUP
        file-extension: yaml
        extension-configs:
          - data-id: user-dev.yml
            group: DEV_GROUP
            refresh: true
          - data-id: user-dev.yml
            group: DEFAULT_GROUP
            refresh: true
        enabled: true
        refresh-enabled: true

elasticsearch:
  connectTimeout: 1000 # http连接超时时间
  socketTimeout: 30000 # socket连接超时时间
  connectionRequestTimeout: 500 # 获取连接的超时时间
  maxConnTotal: 100  # 最大连接数
  maxConnPerRoute: 100 # 最大路由连接数
  executeTimeout: 8  # 任务最长可执行时间 (单位:小时)



#    sentinel:
#      enabled: true
#      eager: true
#      transport:
#        dashboard: localhost:8718
#        port: 8718
#  aop:
#    #采用CGLIB作为作为动态代理，默认true  为了解决使用 JDK 动态代理可能导致的类型转化异常而默认使用 CGLIB (boot1.x版本默认是false)
#    proxy-target-class: true
#    #是否开启aop自动配置，默认为true
#    #意味着自动加上 @EnableAspectAutoProxy 注解
#    #该注解用于开启AOP相关注解得支持
#    auto: true

# 正确配置:
#nacos:
#  config:
#    server-addr: 127.0.0.1:8848
#    type: yaml
#    bootstrap:
#      enable: true
#  discovery:
#    server-addr: 127.0.0.1:8848
feign:
  okhttp:
    enabled: true

再看看启动类，启动类上加了服务调用的注解，@EnableFeignClients。

package com.example.user;

import com.alibaba.nacos.api.annotation.NacosProperties;
import com.alibaba.nacos.spring.context.annotation.config.EnableNacosConfig;
import com.alibaba.nacos.spring.context.annotation.config.NacosPropertySource;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Configuration;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
@EnableNacosConfig(globalProperties = @NacosProperties(serverAddr = "127.0.0.1:8848"))
//@NacosPropertySource(dataId = "user-dev.yml", groupId = "DEV_GROUP",autoRefreshed = true)
@RefreshScope
public class UserApplication {

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

}

这是一个简单的搭建思路。其中nacos不懂的需要下去学习学习。主要是maven的统一管理。cloud 的一些yml配置。