Spring Cloud Alibaba学习01Nacos基本使用(注册中心)

1、注册中心对比：

2、下载与安装：

下载地址：Releases · alibaba/nacos (github.com)

下载后解压缩，进入config目录，打开application.properties文件，修改：

### If use MySQL as datasource:
spring.datasource.platform=mysql

### Count of DB:
db.num=1

### Connect URL of DB:
db.url.0=jdbc:mysql://127.0.0.1:3306/nacos?characterEncoding=utf8&connectTimeout=1000&socketTimeout=3000&autoReconnect=true&useUnicode=true&useSSL=false&serverTimezone=Asia/Shanghai
db.user.0=root
db.password.0=123456

### Connection pool configuration: hikariCP
db.pool.config.connectionTimeout=30000
db.pool.config.validationTimeout=10000
db.pool.config.maximumPoolSize=20
db.pool.config.minimumIdle=2

打开本地mysql数据库的管理软件，新建nacos数据库。并执行config目录下的nacos-mysql.sql文件。创建nacos相关的表。

进入bin目录，使用命令如下命令启动：

ubuntu系统：

cd bin
./startup.sh -m standalone

windows系统：

startup.cmd -m standalone

打开浏览器访问 http://localhost:8848/nacos

用户名：nacos

密码：nacos

即可打开nacos管理后台。

3、确定环境版本：

版本说明：版本说明 · alibaba/spring-cloud-alibaba Wiki (github.com)

本文使用的版本为：

SpringCloud-alibaba版本：2.2.5.RELEASE

SpringCloud版本：Hoxton.SR8

SpringBoot版本：2.3.2RELEASE

4、代码示例：

4.1 父项目

使用IDEA建立一个空的Maven项目，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>org.yas</groupId>
    <artifactId>cloud-demo01</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>cloud-goods</module>
        <module>cloud-entity</module>
        <module>cloud-order</module>
    </modules>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.2.RELEASE</version>
        <relativePath></relativePath>
    </parent>
    <packaging>pom</packaging>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.2.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR8</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
</project>

4.2 实体模块，cloud-entity：

pom文件引入lombok

<?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>cloud-demo01</artifactId>
        <groupId>org.yas</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>cloud-entity</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
</project>

实体类：

 1 package com.yas;
 2 
 3 import lombok.AllArgsConstructor;
 4 import lombok.Data;
 5 import lombok.NoArgsConstructor;
 6 
 7 @Data
 8 @NoArgsConstructor
 9 @AllArgsConstructor
10 public class Goods {
11     private String goodName;
12     private double price;
13 }

4.3 服务提供者模块，cloud-goods：

pom文件内容：

<?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>cloud-demo01</artifactId>
        <groupId>org.yas</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>cloud-goods</artifactId>
    <dependencies>
        <!-- web场景依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- 端点监控场景依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!-- nacos场景依赖 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.yas</groupId>
            <artifactId>cloud-entity</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
</project>

配置文件，application.yml

spring:
  application:
    name: cloud-goods #服务名称，必须唯一
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #指定nacos服务地址
        username: nacos
        password: nacos
server:
  port: 9901

启动类：

 1 package com.yas;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 6 
 7 @SpringBootApplication
 8 @EnableDiscoveryClient//开启服务注册与发现功能
 9 public class GoodApp {
10     public static void main(String[] args) {
11         SpringApplication.run(GoodApp.class);
12     }
13 }

测试Controller：

 1 package com.yas.controller;
 2 
 3 import com.yas.Goods;
 4 import org.springframework.web.bind.annotation.PathVariable;
 5 import org.springframework.web.bind.annotation.RequestMapping;
 6 import org.springframework.web.bind.annotation.RestController;
 7 
 8 @RestController
 9 @RequestMapping("/goods")
10 public class GoodsController {
11     @RequestMapping("/findById/{id}")
12     public Goods findById(@PathVariable String id) {
13         System.out.println("id=" + id);
14         return new Goods("小米", 99);
15     }
16 }

4.4 服务消费者模块，cloud-order：

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">
    <parent>
        <artifactId>cloud-demo01</artifactId>
        <groupId>org.yas</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>cloud-order</artifactId>
    <dependencies>
        <!-- web场景依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- 端点监控场景依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!-- nacos场景依赖 -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.yas</groupId>
            <artifactId>cloud-entity</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
</project>

配置文件，application.yml：

spring:
  application:
    name: cloud-order #服务名称，必须唯一
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #指定nacos服务地址
        username: nacos
        password: nacos
server:
  port: 9900

启动类：

 1 package com.yas;
 2 
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 6 import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 7 import org.springframework.context.annotation.Bean;
 8 import org.springframework.web.client.RestTemplate;
 9 
10 @SpringBootApplication
11 @EnableDiscoveryClient
12 public class OrderApp {
13     public static void main(String[] args) {
14         SpringApplication.run(OrderApp.class);
15     }
16 
17     @Bean
18     @LoadBalanced//使用Ribon调用服务，将域名请求变为服务地址请求
19     public RestTemplate initRestTemplate() {
20         return new RestTemplate();
21     }
22 }

测试Controller：

 1 package com.yas.controller;
 2 
 3 import com.yas.Goods;
 4 import org.springframework.beans.factory.annotation.Autowired;
 5 import org.springframework.web.bind.annotation.RequestMapping;
 6 import org.springframework.web.bind.annotation.RestController;
 7 import org.springframework.web.client.RestTemplate;
 8 
 9 import java.util.HashMap;
10 import java.util.Map;
11 
12 @RestController
13 @RequestMapping("/order")
14 public class OrderController {
15 
16     @Autowired
17     RestTemplate restTemplate;
18 
19     @RequestMapping("/save")
20     public Map save() {
21         //远程调用cloud-goods服务，获取goods信息，发送http请求(httpclient)
22         //硬编码的方式
23 //        String uri1 = "http://localhost:9901/goods/findById/1";
24 //        Goods goods = restTemplate.getForObject(uri1, Goods.class);
25 
26         String serviceName = "cloud-goods";
27         String uri2 = "http://" + serviceName + "/goods/findById/1";
28         Goods goods = restTemplate.getForObject(uri2, Goods.class);
29         System.out.println(goods);
30         
31         //模拟保存订单
32         System.out.println("save order success");
33         Map<String, String> map = new HashMap<>();
34         map.put("code", "200");
35         map.put("msg", "success");
36         return map;
37     }
38 }

5、测试：

启动服务提供者和服务消费者，在8848端口的管理平台查询到两个服务：

使用postman请求地址：localhost:9900/order/save

得到如下结果：

6、Nacos领域模型：

nacos的服务由三元组唯一确定：namespace、group、servicename

nacos的配置由三元组唯一确定：namespace、group、dataId

不同的namespace是相互隔离的，相同namespace但是不同的group也是相互隔离的。

默认的namespace是public，不能删除。

默认的group是DEFAULT_GROUP。