apollo与springboot集成实现动态刷新配置的教程详解

分布式apollo简介

Apollo（阿波罗）是携程框架部门研发的开源配置管理中心，能够集中化管理应用不同环境、不同集群的配置，配置修改后能够实时推送到应用端，并且具备规范的权限、流程治理等特性。

本文主要介绍如何使用apollo与springboot实现动态刷新配置，如果之前不了解apollo可以查看如下文档

https://github.com/ctripcorp/apollo

学习了解一下apollo，再来查看本文

正文

apollo与spring实现动态刷新配置本文主要演示2种刷新，一种基于普通字段刷新、一种基于bean上使用了@ConfigurationProperties刷新

1、普通字段刷新

a、pom.xml配置

 <dependency>
  <groupId>com.ctrip.framework.apollo</groupId>
  <artifactId>apollo-client</artifactId>
  <version>1.6.0</version>
 </dependency>

b、客户端配置AppId，Apollo Meta Server

此配置有多种方法，本示例直接在application.yml配置，配置内容如下

app:
  id: ${spring.application.name}
apollo:
  meta: http://192.168.88.128:8080,http://192.168.88.129:8080
  bootstrap:
    enabled: true
    eagerLoad:
      enabled: true

c、项目中启动类上加上@EnableApolloConfig注解，形如下

@SpringBootApplication
@EnableApolloConfig(value = {"application","user.properties","product.properties","order.properties"})
public class ApolloApplication {

	public static void main(String[] args) {

		SpringApplication.run(ApolloApplication.class, args);
	}

}

@EnableApolloConfig不一定要加在启动类上，加在被spring管理的类上即可

d、在需刷新的字段上配置@Value注解，形如

 @Value("${hello}")
 private String hello;

通过以上三步就可以实现普通字段的动态刷新

2.bean使用@ConfigurationProperties动态刷新

bean使用@ConfigurationProperties注解目前还不支持自动刷新，得编写一定的代码实现刷新。目前官方提供2种刷新方案

• 基于RefreshScope实现刷新
• 基于EnvironmentChangeEvent实现刷新
• 本文再提供一种，当bean上如果使用了@ConditionalOnProperty如何实现刷新

a、基于RefreshScope实现刷新

1、pom.xml要额外引入

 <dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-context</artifactId>
  <version>2.0.3.RELEASE</version>
 </dependency>

2、bean上使用@RefreshScope注解

@Component
@ConfigurationProperties(prefix = "product")
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
@RefreshScope
public class Product {

 private Long id;

 private String productName;

 private BigDecimal price;

}

3、利用RefreshScope搭配@ApolloConfigChangeListener监听实现bean的动态刷新，其代码实现如下

@ApolloConfigChangeListener(value="product.properties",interestedKeyPrefixes = {"product."})
 private void refresh(ConfigChangeEvent changeEvent){

 refreshScope.refresh("product");

 PrintChangeKeyUtils.printChange(changeEvent);
 }

b、基于EnvironmentChangeEvent实现刷新

利用spring的事件驱动配合@ApolloConfigChangeListener监听实现bean的动态刷新，其代码如下

@Component
@Slf4j
public class UserPropertiesRefresh implements ApplicationContextAware {

 private ApplicationContext applicationContext;

 @ApolloConfigChangeListener(value="user.properties",interestedKeyPrefixes = {"user."})
 private void refresh(ConfigChangeEvent changeEvent){
 applicationContext.publishEvent(new EnvironmentChangeEvent(changeEvent.changedKeys()));

 PrintChangeKeyUtils.printChange(changeEvent);
 }

 @Override
 public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 this.applicationContext = applicationContext;
 }
}

c、当bean上有@ConditionalOnProperty如何实现刷新

当bean上有@ConditionalOnProperty注解时，上述的两种方案可以说失效了，因为@ConditionalOnProperty是一个条件注解，当不满足条件注解时，bean是没法注册到spring容器中的。如果我们要实现此种情况的下的动态刷新，我们就得自己手动注册或者销毁bean了。其实现流程如下

1、当满足条件注解时，则手动创建bean，然后配合@ApolloConfigChangeListener监听该bean的属性变化。当该bean属性有变化时，手动把属性注入bean。同时刷新依赖该bean的其他bean

2、当不满足条件注解时，则手动从spring容器中移除bean，同时刷新依赖该bean的其他bean

其刷新核心代码如下

public class OrderPropertiesRefresh implements ApplicationContextAware {

 private ApplicationContext applicationContext;

 @ApolloConfig(value = "order.properties")
 private Config config;

 @ApolloConfigChangeListener(value="order.properties",interestedKeyPrefixes = {"order."},interestedKeys = {"model.isShowOrder"})
 private void refresh(ConfigChangeEvent changeEvent){
 for (String basePackage : listBasePackages()) {
  Set<Class> conditionalClasses = ClassScannerUtils.scan(basePackage, ConditionalOnProperty.class);
  if(!CollectionUtils.isEmpty(conditionalClasses)){
  for (Class conditionalClass : conditionalClasses) {
   ConditionalOnProperty conditionalOnProperty = (ConditionalOnProperty) conditionalClass.getAnnotation(ConditionalOnProperty.class);
   String[] conditionalOnPropertyKeys = conditionalOnProperty.name();
   String beanChangeCondition = this.getChangeKey(changeEvent,conditionalOnPropertyKeys);
   String conditionalOnPropertyValue = conditionalOnProperty.havingValue();
   boolean isChangeBean = this.changeBean(conditionalClass, beanChangeCondition, conditionalOnPropertyValue);
   if(!isChangeBean){
   // 更新相应的bean的属性值，主要是存在@ConfigurationProperties注解的bean
   applicationContext.publishEvent(new EnvironmentChangeEvent(changeEvent.changedKeys()));
   }
  }
  }
 }

 PrintChangeKeyUtils.printChange(changeEvent);
 printAllBeans();
 }

 /**
 * 根据条件对bean进行注册或者移除
 * @param conditionalClass
 * @param beanChangeCondition bean发生改变的条件
 * @param conditionalOnPropertyValue
 */
 private boolean changeBean(Class conditionalClass, String beanChangeCondition, String conditionalOnPropertyValue) {
 boolean isNeedRegisterBeanIfKeyChange = this.isNeedRegisterBeanIfKeyChange(beanChangeCondition,conditionalOnPropertyValue);
 boolean isNeedRemoveBeanIfKeyChange = this.isNeedRemoveBeanIfKeyChange(beanChangeCondition,conditionalOnPropertyValue);
 String beanName = StringUtils.uncapitalize(conditionalClass.getSimpleName());
 if(isNeedRegisterBeanIfKeyChange){
  boolean isAlreadyRegisterBean = this.isExistBean(beanName);
  if(!isAlreadyRegisterBean){
  this.registerBean(beanName,conditionalClass);
  return true;
  }
 }else if(isNeedRemoveBeanIfKeyChange){
  this.unregisterBean(beanName);
  return true;
 }
 return false;
 }

 /**
 * bean注册
 * @param beanName
 * @param beanClass
 */
 public void registerBean(String beanName,Class beanClass) {
 log.info("registerBean->beanName:{},beanClass:{}",beanName,beanClass);
 BeanDefinitionBuilder beanDefinitionBurinilder = BeanDefinitionBuilder.genericBeanDefinition(beanClass);
 BeanDefinition beanDefinition = beanDefinitionBurinilder.getBeanDefinition();
 setBeanField(beanClass, beanDefinition);
 getBeanDefinitionRegistry().registerBeanDefinition(beanName,beanDefinition);

 }

 /**
 * 设置bean字段值
 * @param beanClass
 * @param beanDefinition
 */
 private void setBeanField(Class beanClass, BeanDefinition beanDefinition) {
 ConfigurationProperties configurationProperties = (ConfigurationProperties) beanClass.getAnnotation(ConfigurationProperties.class);
 if(ObjectUtils.isNotEmpty(configurationProperties)){
  String prefix = configurationProperties.prefix();
  for (String propertyName : config.getPropertyNames()) {
  String fieldPrefix = prefix + ".";
  if(propertyName.startsWith(fieldPrefix)){
   String fieldName = propertyName.substring(fieldPrefix.length());
   String fieldVal = config.getProperty(propertyName,null);
   log.info("setBeanField-->fieldName:{},fieldVal:{}",fieldName,fieldVal);
   beanDefinition.getPropertyValues().add(fieldName,fieldVal);
  }
  }
 }
 }

 /**
 * bean移除
 * @param beanName
 */
 public void unregisterBean(String beanName){
 log.info("unregisterBean->beanName:{}",beanName);
 getBeanDefinitionRegistry().removeBeanDefinition(beanName);
 }

 public <T> T getBean(String name) {
 return (T) applicationContext.getBean(name);
 }

 public <T> T getBean(Class<T> clz) {
 return (T) applicationContext.getBean(clz);
 }

 public boolean isExistBean(String beanName){
 return applicationContext.containsBean(beanName);
 }

 public boolean isExistBean(Class clz){
 try {
  Object bean = applicationContext.getBean(clz);
  return true;
 } catch (BeansException e) {
  // log.error(e.getMessage(),e);
 }
 return false;
 }

 private boolean isNeedRegisterBeanIfKeyChange(String changeKey,String conditionalOnPropertyValue){
 if(StringUtils.isEmpty(changeKey)){
  return false;
 }
 String apolloConfigValue = config.getProperty(changeKey,null);
 return conditionalOnPropertyValue.equals(apolloConfigValue);
 }

 private boolean isNeedRemoveBeanIfKeyChange(String changeKey,String conditionalOnPropertyValue){
 if(!StringUtils.isEmpty(changeKey)){
  String apolloConfigValue = config.getProperty(changeKey,null);
  return !conditionalOnPropertyValue.equals(apolloConfigValue);
 }

 return false;

 }

 private boolean isChangeKey(ConfigChangeEvent changeEvent,String conditionalOnPropertyKey){
 Set<String> changeKeys = changeEvent.changedKeys();
 if(!CollectionUtils.isEmpty(changeKeys) && changeKeys.contains(conditionalOnPropertyKey)){
  return true;
 }
 return false;
 }

 private String getChangeKey(ConfigChangeEvent changeEvent, String[] conditionalOnPropertyKeys){
 if(ArrayUtils.isEmpty(conditionalOnPropertyKeys)){
  return null;
 }
 String changeKey = null;
 for (String conditionalOnPropertyKey : conditionalOnPropertyKeys) {
  if(isChangeKey(changeEvent,conditionalOnPropertyKey)){
  changeKey = conditionalOnPropertyKey;
  break;
  }
 }

 return changeKey;
 }

 private BeanDefinitionRegistry getBeanDefinitionRegistry(){
 ConfigurableApplicationContext configurableContext = (ConfigurableApplicationContext) applicationContext;
 BeanDefinitionRegistry beanDefinitionRegistry = (DefaultListableBeanFactory) configurableContext.getBeanFactory();
 return beanDefinitionRegistry;
 }

 private List<String> listBasePackages(){
 ConfigurableApplicationContext configurableContext = (ConfigurableApplicationContext) applicationContext;
 return AutoConfigurationPackages.get(configurableContext.getBeanFactory());
 }

 @Override
 public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 this.applicationContext = applicationContext;
 }

 public void printAllBeans() {
 String[] beans = applicationContext.getBeanDefinitionNames();
 Arrays.sort(beans);
 for (String beanName : beans) {
  Class<?> beanType = applicationContext.getType(beanName);
  System.out.println(beanType);
 }
 }
}

如果条件注解的值也是配置在apollo上，可能会出现依赖条件注解的bean的其他bean，在项目拉取apollo配置时，就已经注入spring容器中，此时就算条件注解满足条件，则引用该条件注解bean的其他bean，也会拿不到条件注解bean。此时有2种方法解决，一种是在依赖条件注解bean的其他bean注入之前，先手动注册条件注解bean到spring容器中，其核心代码如下

@Component
@Slf4j
public class RefreshBeanFactory implements BeanFactoryPostProcessor {

 @Override
 public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
 Config config = ConfigService.getConfig("order.properties");
 List<String> basePackages = AutoConfigurationPackages.get(configurableListableBeanFactory);
 for (String basePackage : basePackages) {
  Set<Class> conditionalClasses = ClassScannerUtils.scan(basePackage, ConditionalOnProperty.class);
  if(!CollectionUtils.isEmpty(conditionalClasses)){
  for (Class conditionalClass : conditionalClasses) {
   ConditionalOnProperty conditionalOnProperty = (ConditionalOnProperty) conditionalClass.getAnnotation(ConditionalOnProperty.class);
   String[] conditionalOnPropertyKeys = conditionalOnProperty.name();
   String beanConditionKey = this.getConditionalOnPropertyKey(config,conditionalOnPropertyKeys);
   String conditionalOnPropertyValue = conditionalOnProperty.havingValue();
   this.registerBeanIfMatchCondition((DefaultListableBeanFactory)configurableListableBeanFactory,config,conditionalClass,beanConditionKey,conditionalOnPropertyValue);
  }
  }
 }

 }

 private void registerBeanIfMatchCondition(DefaultListableBeanFactory beanFactory,Config config,Class conditionalClass, String beanConditionKey, String conditionalOnPropertyValue) {
 boolean isNeedRegisterBean = this.isNeedRegisterBean(config,beanConditionKey,conditionalOnPropertyValue);
 String beanName = StringUtils.uncapitalize(conditionalClass.getSimpleName());
 if(isNeedRegisterBean){
  this.registerBean(config,beanFactory,beanName,conditionalClass);

 }

 }

 public void registerBean(Config config,DefaultListableBeanFactory beanFactory, String beanName, Class beanClass) {
 log.info("registerBean->beanName:{},beanClass:{}",beanName,beanClass);
 BeanDefinitionBuilder beanDefinitionBurinilder = BeanDefinitionBuilder.genericBeanDefinition(beanClass);
 BeanDefinition beanDefinition = beanDefinitionBurinilder.getBeanDefinition();
 setBeanField(config,beanClass, beanDefinition);
 beanFactory.registerBeanDefinition(beanName,beanDefinition);

 }

 private void setBeanField(Config config,Class beanClass, BeanDefinition beanDefinition) {
 ConfigurationProperties configurationProperties = (ConfigurationProperties) beanClass.getAnnotation(ConfigurationProperties.class);
 if(ObjectUtils.isNotEmpty(configurationProperties)){
  String prefix = configurationProperties.prefix();
  for (String propertyName : config.getPropertyNames()) {
  String fieldPrefix = prefix + ".";
  if(propertyName.startsWith(fieldPrefix)){
   String fieldName = propertyName.substring(fieldPrefix.length());
   String fieldVal = config.getProperty(propertyName,null);
   log.info("setBeanField-->fieldName:{},fieldVal:{}",fieldName,fieldVal);
   beanDefinition.getPropertyValues().add(fieldName,fieldVal);
  }
  }
 }
 }

 public boolean isNeedRegisterBean(Config config,String beanConditionKey,String conditionalOnPropertyValue){
 if(StringUtils.isEmpty(beanConditionKey)){
  return false;
 }
 String apolloConfigValue = config.getProperty(beanConditionKey,null);
 return conditionalOnPropertyValue.equals(apolloConfigValue);
 }

 private String getConditionalOnPropertyKey(Config config, String[] conditionalOnPropertyKeys){
 if(ArrayUtils.isEmpty(conditionalOnPropertyKeys)){
  return null;
 }
 String changeKey = null;
 for (String conditionalOnPropertyKey : conditionalOnPropertyKeys) {
  if(isConditionalOnPropertyKey(config,conditionalOnPropertyKey)){
  changeKey = conditionalOnPropertyKey;
  break;
  }
 }

 return changeKey;
 }
 private boolean isConditionalOnPropertyKey(Config config,String conditionalOnPropertyKey){
 Set<String> propertyNames = config.getPropertyNames();
 if(!CollectionUtils.isEmpty(propertyNames) && propertyNames.contains(conditionalOnPropertyKey)){
  return true;
 }
 return false;
 }
}

其次利用懒加载的思想，在使用条件注解bean时，使用形如下方法

Order order = (Order) 
SpringContextUtils.getBean("order");

总结

本文主要介绍了常用的动态刷新，但本文的代码示例实现的功能不局限于此，本文的代码还实现如何通过自定义注解与apollo整合来实现一些业务操作，同时也实现了基于hystrix注解与apollo整合，实现基于线程隔离的动态熔断，感兴趣的朋友可以复制文末链接到浏览器，进行查看

apollo基本上是能满足我们日常的业务开发要求，但是对于一些需求，比如动态刷新线上数据库资源啥，我们还是得做一定的量的改造，好在携程也提供了apollo-use-cases，在里面可以找到常用的使用场景以及示例代码，其链接如下

https://github.com/ctripcorp/apollo-use-cases

感兴趣的朋友，可以查看下。

demo链接

https://github.com/lyb-geek/springboot-learning/tree/master/springboot-apollo

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