[Java知识库]SpringCloud Alibaba

Nacos服务注册和配置中心

Nacos就是注册中心 + 配置中心的组合，Nacos = Eureka+Config +Bus
替代Eureka做服务注册中心，替代Config做服务配置中心
安装运行访问http://localhost:8848/nacos默认账号密码都是nacos

为什么nacos支持负载均衡

Nacos作为服务注册中心演示

基于Nacos的服务提供者

父POM

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.1.9.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.0.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>5.1.47</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.16</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.0</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
                <optional>true</optional>
            </dependency>
        </dependencies>
    </dependencyManagement>

本模块pom

    <artifactId>cloudalibaba-provider-payment9001</artifactId>

    <dependencies>
        <!--SpringCloud ailibaba nacos -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- SpringBoot整合Web组件 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--日常通用jar包配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

server:
  port: 9001

spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #配置Nacos地址

management:
  endpoints:
    web:
      exposure:
        include: '*'

@EnableDiscoveryClient
@SpringBootApplication
public class PaymentMain9001
{
    public static void main(String[] args) {
            SpringApplication.run(PaymentMain9001.class, args);
    }
}

@RestController
public class PaymentController
{
    @Value("${server.port}")
    private String serverPort;

    @GetMapping(value = "/payment/nacos/{id}")
    public String getPayment(@PathVariable("id") Integer id)
    {
        return "nacos registry, serverPort: "+ serverPort+"\t id"+id;
    }
}

基于Nacos的服务消费者

    <artifactId>cloudalibaba-consumer-nacos-order83</artifactId>



    <dependencies>
        <!--SpringCloud ailibaba nacos -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>
        <!-- SpringBoot整合Web组件 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--日常通用jar包配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

server:
  port: 83


spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848


#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)
service-url:
  nacos-user-service: http://nacos-payment-provider 

@EnableDiscoveryClient
@SpringBootApplication
public class OrderNacosMain83
{
    public static void main(String[] args)
    {
        SpringApplication.run(OrderNacosMain83.class,args);
    }
} 

@RestController
public class PaymentController
{
    @Value("${server.port}")
    private String serverPort;

    @GetMapping(value = "/payment/{id}")
    public String getPayment(@PathVariable("id") Integer id)
    {
        return "nacos registry, serverPort: "+ serverPort+"\t id"+id;
    }
}

支持ap，cp模式切换

C是所有节点在同一时间看到的数据是一致的；而A的定义是所有的请求都会收到响应。

何时选择使用何种模式？
一般来说，
如果不需要存储服务级别的信息且服务实例是通过nacos-client注册，并能够保持心跳上报，那么就可以选择AP模式。当前主流的服务如 Spring cloud 和 Dubbo 服务，都适用于AP模式，AP模式为了服务的可能性而减弱了一致性，因此AP模式下只支持注册临时实例。

如果需要在服务级别编辑或者存储配置信息，那么 CP 是必须，K8S服务和DNS服务则适用于CP模式。
CP模式下则支持注册持久化实例，此时则是以 Raft 协议为集群运行模式，该模式下注册实例之前必须先注册服务，如果服务不存在，则会返回错误。

curl -X PUT '$NACOS_SERVER:8848/nacos/v1/ns/operator/switches?entry=serverMode&value=CP'

Nacos作为服务配置中心演示

Nacos作为配置中心-基础配置

    <artifactId>cloudalibaba-config-nacos-client3377</artifactId>



    <dependencies>
        <!--nacos-config-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>
        <!--nacos-discovery-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--web + actuator-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--一般基础配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

bootstrap

# nacos配置
server:
  port: 3377

spring:
  application:
    name: nacos-config-client
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos服务注册中心地址
      config:
        server-addr: localhost:8848 #Nacos作为配置中心地址
        file-extension: yaml #指定yaml格式的配置
 
 
# ${spring.application.name}-${spring.profile.active}.${spring.cloud.nacos.config.file-extension}

application

spring:
  profiles:
    active: dev # 表示开发环境

Nacos同springcloud-config一样，在项目初始化时，要保证先从配置中心进行配置拉取，
拉取配置之后，才能保证项目的正常启动。

springboot中配置文件的加载是存在优先级顺序的，bootstrap优先级高于application

@EnableDiscoveryClient
@SpringBootApplication
public class NacosConfigClientMain3377
{
    public static void main(String[] args) {
            SpringApplication.run(NacosConfigClientMain3377.class, args);
    }
}

@RestController
@RefreshScope //在控制器类加入@RefreshScope注解使当前类下的配置支持Nacos的动态刷新功能。
public class ConfigClientController
{
    @Value("${config.info}")
    private String configInfo;

    @GetMapping("/config/info")
    public String getConfigInfo() {
        return configInfo;
    }
}

在Nacos中添加配置信息

Nacos中的dataid的组成格式及与SpringBoot配置文件中的匹配规则

${spring.application.name}-${spring.profiles.active}.${spring.cloud.nacos.config.file-extension}

Nacos集群和持久化配置（重要）

Nacos持久化配置解释

Nacos默认自带的是嵌入式数据库derby

derby到mysql切换配置步骤
nacos-server-1.1.4\nacos\conf目录下找到sql脚本并执行
nacos-server-1.1.4\nacos\conf目录下找到application.properties

spring.datasource.platform=mysql
 
db.num=1
db.url.0=jdbc:mysql://127.0.0.1:3306/nacos_config?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true
db.user=root
db.password=123456

Linux版Nacos+MySQL生产环境配置

nacos下载linux版

Linux服务器上mysql数据库配置

application.properties 配置

spring.datasource.platform=mysql
 
db.num=1
db.url.0=jdbc:mysql://127.0.0.1:3306/nacos_config?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true
db.user=root
db.password=123456

Linux服务器上nacos的集群配置cluster.conf

梳理出3台nacos集器的不同服务端口号

编辑Nacos的启动脚本startup.sh，使它能够接受不同的启动端口

/mynacos/nacos/bin 目录下有startup.sh

修改前


修改后


Nginx的配置，由它作为负载均衡器

Sentinel实现熔断与限流