Spring Cloud Alibaba：使用Nacos作为配置中心

落日映苍穹つ 2023-02-11 11:23 24阅读 0赞

**1.由于分布式项目的配置管理，现在大多的配置文件都是在网络上，比如git、码云上面，这样易于维护。**

**2.上一篇博文介绍了nacos的服务注册与发现，现在基于nacos-provider实现config配置中心。**

**项目实现：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70][]

**pom.xml 主要新增了spring-cloud-alibaba-nacos-config该依赖**

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.3.0.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.cxb</groupId>
        <artifactId>springcloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>nacos-provider</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</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>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
                <version>0.9.0.RELEASE</version>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-nacos-config</artifactId>
                <version>0.9.0.RELEASE</version>
            </dependency>
    
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>
    
    </project>

**重点：**在bootstrap.yml(一定是bootstrap.yml文件，不是application.yml（可以删除了）文件)文件配置以下内容：这里项目的启动端口号在远端配置好了。

spring:
      application:
        name: nacos-provider
      cloud:
        nacos:
          discovery:
            server-addr: 127.0.0.1:8848
          config:
            server-addr: 127.0.0.1:8848
            file-extension: yaml
            prefix: nacos-provider
      profiles:
        active: dev

上面的配置是和Nacos中的`dataId` 的格式是对应的，nacos的完整格式如下：

**$\{prefix\}-$\{spring.profile.active\}.$\{file-extension\}**

**`prefix` ：**默认为 `spring.application.name` 的值，也可以通过配置项 `spring.cloud.nacos.config.prefix`来配置。

**spring.profile.active** ：即为当前环境对应的 profile，详情可以参考 Spring Boot文档。 注意：当 spring.profile.active 为空时，对应的连接符 - 也将不存在，dataId 的拼接格式变成 $\{prefix\}.$\{file-extension\}  
**`file-exetension` ：**为配置内容的数据格式，可以通过配置项 `spring.cloud.nacos.config.file-extension` 来配置。目前只支持 `properties` 和 `yaml` 类型。

通过以上的了解，登陆localhost:8848/nacos，创建一个data id ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70 1][]

根据项目具体情况配置data id为：**nacos-provider-dev.yaml**

**在配置内容里面配置具体的信息即可。**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70 2][]

ProviderController在控制器里获取上面的配置信息

package com.cxb.springcloud.web;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.cloud.context.config.annotation.RefreshScope;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    //实现配置的热加载
    @RefreshScope
    public class ProviderController {
    
        Logger logger = LoggerFactory.getLogger(ProviderController.class);
    
        @Value("${username:frank}")
        private String username;
    
        @Value("${address:china}")
        private String address;
    
        @RequestMapping("/getInfo")
        public String getInfo() {
            return address + ":"+ username;
        }
    
        @GetMapping("/hi")
        public String hi(@RequestParam(value = "name",defaultValue = "frank",required = false)String name){
            logger.info("name:{}", name);
            return "hi "+name;
        }
    }

启动类：

package com.cxb.springcloud;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    public class NacosProviderApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(NacosProviderApplication.class, args);
        }
    
    }

最后启动项目测试：

[http://localhost:8766/getInfo][http_localhost_8766_getInfo] 8766端口就是远端配置的端口号

![20200523151335532.png][]

成功获取配置的信息，修改配置信息，再重新加载，返回的是修改后的值，可见nacos作为配置中心实现了热加载功能。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200523144648441.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200523145335996.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200523151204348.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzMzcxNzY2,size_16,color_FFFFFF,t_70
[http_localhost_8766_getInfo]: http://localhost:8762/getInfo
[20200523151335532.png]: https://img-blog.csdnimg.cn/20200523151335532.png