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nacos

nacos下载

下载地址

一键傻瓜试安装即可,官网写的很清楚这里不在赘述 http://nacos.io/zh-cn/docs/v2/quickstart/quick-start.html

nacos启动

将模式改为单机模式

启动成功

nacos相关配置

demo-dev.yaml

server:port: 8001config:info: "config info for dev from nacos config center"

demo-test.yaml

server:port: 3333config:info: "config info for test from nacos config center"

user.yaml

user:name: zs1112222age: 10address: 测试地址

代码

整合nacos配置中心,注册中心,完整项目地址 gitee地址

pom.xml

<parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.2.2.RELEASE</version>
</parent><dependencies><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><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></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId><version>2.2.2.RELEASE</version></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId><version>2.2.2.RELEASE</version></dependency>
</dependencies>

UserConfig

@Data
@Configuration
@ConfigurationProperties(prefix = "user")
public class UserConfig {private String name;private Integer age;private String address;}

BeanAutoRefreshConfigExample

@RestController
public class BeanAutoRefreshConfigExample {@Autowiredprivate UserConfig userConfig;@GetMapping("/user/hello")public String hello(){return userConfig.getName() + userConfig.getAge() + userConfig.getAddress();}}

ValueAnnotationExample

@RestController
@RefreshScope
public class ValueAnnotationExample {@Value("${config.info}")private String configInfo;@GetMapping("/config/info")public String getConfigInfo() {return configInfo;}}

DemoApplication

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

bootstrap.yml

spring:profiles:# 指定环境 切换环境active: devapplication:name: democloud:# nacos server dataId# ${spring.application.name)}-${spring.profiles.active}.${spring.cloud.nacos.config.file-extension}nacos:# Nacos服务注册中心discovery:serverAddr: @serverAddr@group: DEMO_GROUPnamespace: 25af15f3-ae79-41c3-847d-960adb953185username: @username@password: @password@# Nacos作为配置中心config:server-addr: @serverAddr@file-extension: yamlgroup: DEMO_GROUPnamespace: 25af15f3-ae79-41c3-847d-960adb953185username: @username@password: @password@# 加载多配置extension-configs:- data-id: user.yamlgroup: DEMO_GROUPrefresh: true

测试结果

补充.刷新静态配置

有时候一些老项目或者一些写法会遇到静态的配置,这时候可以利用Java的反射特性来刷新静态变量.

大致原理为: 监听nacos配置改动,通过nacos改动确定改动的配置,进而缩小更新范围,通过反射更新变量.

<!-- https://mvnrepository.com/artifact/com.purgeteam/dynamic-config-spring-boot-starter -->
<dependency><groupId>com.purgeteam</groupId><artifactId>dynamic-config-spring-boot-starter</artifactId><version>0.1.1.RELEASE</version>
</dependency>
<dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId>
</dependency>

@NacosRefreshStaticField

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface NacosRefreshStaticField {String configPrefix() default "";}

NacosListener

@Slf4j
@Component
@EnableDynamicConfigEvent
public class NacosListener implements ApplicationListener<ActionConfigEvent> {@Autowiredprivate ApplicationContext applicationContext;@SneakyThrows@Overridepublic void onApplicationEvent(ActionConfigEvent environment) {Map<String, HashMap> map = environment.getPropertyMap();for (Map.Entry<String, HashMap> entry : map.entrySet()) {String key = entry.getKey();Map changeMap = entry.getValue();String before = String.valueOf(changeMap.get("before"));String after = String.valueOf(changeMap.get("after"));log.info("配置[key:{}]被改变，改变前before：{}，改变后after：{}",key,before,after);String[] configNameArr = key.split("\\.");String configPrefix = configNameArr[0];String configRealVal = configNameArr[configNameArr.length-1];AtomicReference<Class<?>> curClazz = new AtomicReference<>();Map<String, Object> refreshStaticFieldBeanMap = applicationContext.getBeansWithAnnotation(NacosRefreshStaticField.class);for (Map.Entry<String, Object> mapEntry : refreshStaticFieldBeanMap.entrySet()) {String beanName = mapEntry.getKey();if (ObjectUtil.isEmpty(beanName)) {continue;}String fullClassName = refreshStaticFieldBeanMap.get(beanName).toString().split("@")[0];Class<?> refreshStaticFieldClass;try {refreshStaticFieldClass = Class.forName(fullClassName);} catch (ClassNotFoundException e) {throw new ClassNotFoundException("监听nacos刷新当前静态类属性,未找到当前类",e);}NacosRefreshStaticField refreshStaticConfig = refreshStaticFieldClass.getAnnotation(NacosRefreshStaticField.class);if (Objects.nonNull(refreshStaticConfig) && refreshStaticConfig.configPrefix().equalsIgnoreCase(configPrefix)) {curClazz.set(refreshStaticFieldClass);}}Class<?> aClass = curClazz.get();if (Objects.isNull(aClass)) {return;}// 利用反射动态更新 静态变量Field[] declaredFields = aClass.getDeclaredFields();for (Field declaredField : declaredFields) {if (declaredField.getName().equalsIgnoreCase(configRealVal)) {log.info("刷新当前配置 更新当前类[{}] 静态属性 [{}]",aClass.getSimpleName(),declaredField.getName());declaredField.setAccessible(true);declaredField.set(null,after);}}}}
}

CommonWebConfig

@Data
@Component
@ConfigurationProperties(prefix = "common")
@RefreshScope
public class CommonWebConfig {private String apiUrl;}

使用

@Component
@NacosRefreshStaticField(configPrefix="common")
public class ExampleComponent {public static String apiUrl = SpringUtil.getBean(CommonWebConfig.class).getApiUrl();
}