配置中心是什么
配置中心,通过key=value的形式存储环境变量。配置中心的属性做了修改,项目中可以通过配置中心的依赖(sdk)立即感知到。需要做的就是如何在属性发生变化时,改变带有@ConfigurationProperties的bean的相关属性。
配置中心原理
在读配置中心源码的时候发现,里面维护了一个Environment,以及ZookeeperPropertySource。当配置中心属性发生变化的时候,清空ZookeeperPropertySource,并放入最新的属性值。
public class ZookeeperPropertySource extends EnumerablePropertySource<Properties>
ZookeeperPropertySource重写了equals和hahscode方法,根据这两个方法可以判定配置中心是否修改了属性。
动态刷新bean属性原理
实现原理图
动态刷新bean父类
public abstract class BaseConfigCenterBean implements InitializingBean {private static Logger LOGGER = LoggerFactory.getLogger(BaseConfigCenterBean.class);//配置中心是否生效protected boolean cfgCenterEffect = false;public boolean isCfgCenterEffect() {this.checkCfgCenterEffect();return cfgCenterEffect;}private void checkCfgCenterEffect() {boolean tmpCfgCenterEffect = !Objects.isNull(ConfigHelper.getEnvironment());if (tmpCfgCenterEffect) {// NOSONARString value = (String) ConfigHelper.getZookeeperPropertySource().getProperty("cfg.center.effect");if (StringUtils.isBlank(value)) {tmpCfgCenterEffect = false;} else {tmpCfgCenterEffect = Boolean.valueOf(value);}}cfgCenterEffect = tmpCfgCenterEffect;if (cfgCenterEffect) {String prefix = this.getConfigPrefix();cfgCenterEffect = Arrays.stream(ConfigHelper.getZookeeperPropertySource().getPropertyNames()).filter(keyName -> keyName.indexOf(prefix) == 0).count() > 0;if (!cfgCenterEffect) {LOGGER.info(String.format("配置中心没有发现模块=%s, prefix=%s的配置,将使用本地配置...", this.getModuleName(), prefix));}}}/*** 绑定自身目标**/protected void doBind() {Class<? extends BaseConfigCenterBean> clazz = this.getClass();if (AopUtils.isCglibProxy(this)) {clazz = (Class<? extends BaseConfigCenterBean>) AopUtils.getTargetClass(this);}BaseConfigCenterBean target = binding(isCfgCenterEffect(), clazz, this.getDefaultResourcePath());this.copyProperties(target);}private void copyProperties(BaseConfigCenterBean target) {ReflectionUtils.doWithFields(this.getClass(), field -> {field.setAccessible(true);field.set(this, field.get(target));}, field -> AnnotatedElementUtils.isAnnotated(field, ConfigField.class));}/*** 绑定其他目标** @param clazz 目标类**/protected <T> T doBind(Class<T> clazz) {T target = binding(isCfgCenterEffect(), clazz, this.getDefaultResourcePath());if (target instanceof InitializingBean) {try {((InitializingBean) target).afterPropertiesSet();} catch (Exception e) {LOGGER.error(String.format("属性初始化失败[afterPropertiesSet], class=%s", ClassUtils.getSimpleName(clazz), e));}}return target;}private <T> T binding(boolean cfgCenterEffect, Class<T> clazz, String defaultResourcePath) {Optional<PropertySource> propertySource = Optional.empty();if (cfgCenterEffect) {propertySource = Optional.ofNullable(ConfigHelper.getZookeeperPropertySource());} else {Optional<ResourcePropertySource> resourcePropertySource = ResourceUtils.getResourcePropertySource(defaultResourcePath);if (resourcePropertySource.isPresent()) {propertySource = Optional.ofNullable(resourcePropertySource.get());}}if (propertySource.isPresent()) {T target;try {target = RelaxedConfigurationBinder.with(clazz).setPropertySources(propertySource.get()).doBind();} catch (GeneralException e) {LOGGER.error(String.format("属性绑定失败, class=%s", ClassUtils.getSimpleName(clazz)), e);return null;}return target;}return null;}@Overridepublic void afterPropertiesSet() {Class<?> target = this.getClass();if (AopUtils.isAopProxy(this)) {target = AopUtils.getTargetClass(this);}LOGGER.info(String.format("%s->%s模块引入配置中心%s...", this.getModuleName(), ClassUtils.getSimpleName(target), (isCfgCenterEffect() ? "生效" : "无效")));}public String getModuleName() {return StringUtils.EMPTY;}@Subscribepublic void listenRefreshEvent(ConfigCenterUtils.ConfigRefreshEvent refreshEvent) {if (!refreshEvent.getModuleName().equals(this.getModuleName())) {this.refreshForEvent();}}//通过事件进行刷新public abstract void refreshForEvent();//获取本地配置默认路径public abstract String getDefaultResourcePath();//获取配置属性的公共前缀public abstract String getConfigPrefix(); }
1、isCfgCenterEffect方法主要判断项目是否接入了配置中心并且配置中心配有bean中相关的属性。
2、binding方法主要根据isCfgCenterEffect方法的返回值去加载配置中心的properties还是本地的properties。
3、getDefaultResourcePath是主要是获取本地资源的默认路径(在没有接入配置中心的情况下)。
4、getConfigPrefix方法返回bean中配置属性的公共前缀(等同于@ConfigurationProperties中的prefix属性)。
5、refreshForEvent方法主要是在某个bean感知到配置中心更新属性时异步通知其他bean进行属性的更新。
bean属性绑定工具类
动态将propertysource绑定到带有@ConfigurationProperties注解的bean中。
参考 org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor
public class RelaxedConfigurationBinder<T> {private final PropertiesConfigurationFactory<T> factory;public RelaxedConfigurationBinder(T object) {this(new PropertiesConfigurationFactory<>(object));}public RelaxedConfigurationBinder(Class<?> type) {this(new PropertiesConfigurationFactory<>(type));}public static <T> RelaxedConfigurationBinder<T> with(T object) {return new RelaxedConfigurationBinder<>(object);}public static <T> RelaxedConfigurationBinder<T> with(Class<T> type) {return new RelaxedConfigurationBinder<>(type);}public RelaxedConfigurationBinder(PropertiesConfigurationFactory<T> factory) {this.factory = factory;ConfigurationProperties properties = getMergedAnnotation(factory.getObjectType(), ConfigurationProperties.class);javax.validation.Validator validator = Validation.buildDefaultValidatorFactory().getValidator();factory.setValidator(new SpringValidatorAdapter(validator));factory.setConversionService(new DefaultConversionService());if (!Objects.isNull(properties)) {//NOSONAR factory.setIgnoreNestedProperties(properties.ignoreNestedProperties());factory.setIgnoreInvalidFields(properties.ignoreInvalidFields());factory.setIgnoreUnknownFields(properties.ignoreUnknownFields());factory.setTargetName(properties.prefix());factory.setExceptionIfInvalid(properties.exceptionIfInvalid());}}public RelaxedConfigurationBinder<T> setTargetName(String targetName) {factory.setTargetName(targetName);return this;}public RelaxedConfigurationBinder<T> setPropertySources(PropertySource<?>... propertySources) {MutablePropertySources sources = new MutablePropertySources();for (PropertySource<?> propertySource : propertySources) {sources.addLast(propertySource);}factory.setPropertySources(sources);return this;}public RelaxedConfigurationBinder<T> setPropertySources(Environment environment) {factory.setPropertySources(((ConfigurableEnvironment) environment).getPropertySources());return this;}public RelaxedConfigurationBinder<T> setPropertySources(PropertySources propertySources) {factory.setPropertySources(propertySources);return this;}public RelaxedConfigurationBinder<T> setConversionService(ConversionService conversionService) {factory.setConversionService(conversionService);return this;}public RelaxedConfigurationBinder<T> setValidator(Validator validator) {factory.setValidator(validator);return this;}public RelaxedConfigurationBinder<T> setResolvePlaceholders(boolean resolvePlaceholders) {factory.setResolvePlaceholders(resolvePlaceholders);return this;}public T doBind() throws GeneralException {try {return factory.getObject();} catch (Exception ex) {throw new GeneralException("配置绑定失败!", ex);}} }
配置中心工具类
public class ConfigCenterUtils {private static Logger LOGGER = LoggerFactory.getLogger(ConfigCenterUtils.class);private static AsyncEventBus eventBus = new AsyncEventBus(Executors.newFixedThreadPool(8));//NOSONARprivate static Properties cfgProperties;private static Environment environment;static {cfgProperties = new Properties();cfgProperties.putAll(ConfigHelper.getZookeeperPropertySource().getProperties());}public static void setEnvironment(Environment environment) {ConfigCenterUtils.environment = environment;}public static String getValue(String name) {try {return PropertiesUtil.getValue(name);} catch (Exception e) {LOGGER.info("配置中心无效, property name=" + name, e);}if (Objects.isNull(environment)) {LOGGER.info("environment无效,property name=" + name);return StringUtils.EMPTY;}if (!environment.containsProperty(name)) {LOGGER.info("environment无配置 property name=" + name);return StringUtils.EMPTY;}return environment.getProperty(name);}public synchronized static boolean propertySourceShouldRefresh(String moduleName, ZookeeperPropertySource newPropertySource) {if (!cfgProperties.equals(newPropertySource.getProperties())) {cfgProperties.clear();cfgProperties.putAll(newPropertySource.getProperties());eventBus.post(new ConfigRefreshEvent(moduleName));return true;}return false;}public static <T> T createToRefreshPropertiesBean(Class<T> clazz) {Enhancer enhancer = new Enhancer();// 设置代理对象父类 enhancer.setSuperclass(clazz);// 标识Spring-generated proxiesenhancer.setInterfaces(new Class[]{SpringProxy.class});// 设置增强enhancer.setCallback((MethodInterceptor) (target, method, args, methodProxy) -> {ToRefresh toRefresh = AnnotationUtils.findAnnotation(method, ToRefresh.class);if (Objects.isNull(toRefresh) || StringUtils.isBlank(toRefresh.method())) {return methodProxy.invokeSuper(target, args);}Method refreshMethod = ReflectionUtils.findMethod(target.getClass(), toRefresh.method());if (Objects.isNull(refreshMethod)) {return methodProxy.invokeSuper(target, args);}refreshMethod = BridgeMethodResolver.findBridgedMethod(refreshMethod);refreshMethod.setAccessible(true);refreshMethod.invoke(target, null);return methodProxy.invokeSuper(target, args);});T target = (T) enhancer.create();// 创建代理对象 MethodIntrospector.selectMethods(clazz, (ReflectionUtils.MethodFilter) method -> AnnotatedElementUtils.isAnnotated(method, ToInitial.class)).stream().findFirst().ifPresent(method -> {method.setAccessible(true);try {method.invoke(target, null);} catch (Exception e) {LOGGER.error(String.format("初始化异常,class=%s ...", ClassUtils.getSimpleName(clazz)), e);}});return target;}public static void registerListener(BaseConfigCenterBean refreshableBean) {eventBus.register(refreshableBean);}public static class ConfigRefreshEvent {private String moduleName;public ConfigRefreshEvent(String moduleName) {this.moduleName = moduleName;}public String getModuleName() {return moduleName;}public void setModuleName(String moduleName) {this.moduleName = moduleName;}} }
这个工具主要作用:
1、判断配置中心的属性是否发生了变化
2、为BaseConfigCenterBean子类创建代理类,使属性在getter方法时检测属性是否应该刷新。
3、提供将BaseConfigCenterBean类型的对象的注册为guava eventbus的监听对象,使之具有根据刷新事件自动刷新自身属性。
bean后置处理器
public class ConfigCenterBeanPostProcessor implements BeanPostProcessor {@Overridepublic Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {if (AnnotatedElementUtils.isAnnotated(bean.getClass(), ConfigCenterBean.class)) {BaseConfigCenterBean refreshableBean = (BaseConfigCenterBean) ConfigCenterUtils.createToRefreshPropertiesBean(bean.getClass());ConfigCenterUtils.registerListener(refreshableBean);return refreshableBean;}return bean;}@Overridepublic Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {return bean;} }
该后置处理器的作用是对所有BaseConfigCenterBean类型的bean进行处理,生成代理bean,并注册为guava eventbus相应的listener。
pojo属性绑定配置中心优雅方案1
@ConfigCenterBean @ConfigurationProperties(prefix = "wx.temporary.qrcode") @Component public class QrcodeConstants extends BaseConfigCenterBean {private static Logger LOGGER = LoggerFactory.getLogger(QrcodeConstants.class);//渠道@ConfigField //标识该属性来自配置中心private List<Scene> channels;//业务 @ConfigFieldprivate List<Scene> bizs;//业务和渠道映射关系 @ConfigFieldprivate Map<String, String> biz2Channel;private Map<String, Scene> channelMap;private Map<String, Scene> bizMap;public List<Scene> getChannels() {return channels;}public void setChannels(List<Scene> channels) {this.channels = channels;}public List<Scene> getBizs() {return bizs;}public void setBizs(List<Scene> bizs) {this.bizs = bizs;}@ToRefresh(method = "toRefresh")public Map<String, Scene> getChannelMap() {return channelMap;}@ToRefresh(method = "toRefresh")public Map<String, Scene> getBizMap() {return bizMap;}@ToRefresh(method = "toRefresh")public Map<String, String> getBiz2Channel() {return biz2Channel;}public void setBiz2Channel(Map<String, String> biz2Channel) {this.biz2Channel = biz2Channel;}@ToInitialprivate void refreshQrcodeProperties() {try {super.doBind();//属性处理if (CollectionUtils.isEmpty(channels)) {this.channelMap = Maps.newHashMap();} else {this.channelMap = channels.stream().collect(Collectors.toMap(channel -> channel.getType(), Function.identity()));}if (CollectionUtils.isEmpty(bizs)) {this.bizMap = Maps.newHashMap();} else {this.bizMap = bizs.stream().collect(Collectors.toMap(biz -> biz.getType(), Function.identity()));}LOGGER.info(String.format("%s 刷新成功..., 当前配置=%s...", this.getModuleName(), this));} catch (Exception e) {LOGGER.error("QrcodeConstants 对象属性绑定失败...", e);}}private void toRefresh() {try {if (isCfgCenterEffect()) {ZookeeperPropertySource propertySource = ConfigHelper.getZookeeperPropertySource();if (ConfigCenterUtils.propertySourceShouldRefresh(this.getModuleName(), propertySource)) {this.refreshQrcodeProperties();}}} catch (Exception e) {LOGGER.error("QrcodeConstants 对象属性刷新失败", e);}}//刷新事件调用 @Overridepublic void refreshForEvent() {this.refreshQrcodeProperties();}//本地资源文件 @Overridepublic String getDefaultResourcePath() {return "config/qrcode.properties";}//属性配置 公共前缀(和@ConfigurationProperties prefix 属性一致) @Overridepublic String getConfigPrefix() {return "wx.temporary.qrcode";}//模块名称 @Overridepublic String getModuleName() {return "微信临时二维码配置";}@Overridepublic String toString() {return ReflectionToStringBuilder.toString(this, ToStringStyle.JSON_STYLE, false, false, QrcodeConstants.class);}public static class Scene {private String type;private String desc;public String getType() {return type;}public void setType(String type) {this.type = type;}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}@Overridepublic String toString() {return ReflectionToStringBuilder.toString(this, ToStringStyle.JSON_STYLE, false, false, Scene.class);}} }
pojo属性绑定配置中心优雅方案2
@ConfigCenterBean @Component public class QrcodeConstants extends BaseConfigCenterBean {private static Logger LOGGER = LoggerFactory.getLogger(QrcodeConstants.class);//业务和渠道映射关系private Map<String, String> biz2Channel;//渠道private Map<String, Scene> channelMap;//业务private Map<String, Scene> bizMap;private QrcodeProperties qrcodeProperties;@ToRefresh(method = "toRefresh")public Map<String, Scene> getChannelMap() {return channelMap;}@ToRefresh(method = "toRefresh")public Map<String, Scene> getBizMap() {return bizMap;}@ToRefresh(method = "toRefresh")public Map<String, String> getBiz2Channel() {return biz2Channel;}public void setBiz2Channel(Map<String, String> biz2Channel) {this.biz2Channel = biz2Channel;}public QrcodeProperties getRawQrcodeProperties() {return qrcodeProperties;}@ToInitialprivate void refreshQrcodeProperties() {try {QrcodeProperties qrcodeProperties = super.doBind(QrcodeProperties.class);if (Objects.isNull(qrcodeProperties)) {LOGGER.error(String.format("没有加载到%s配置,请检查配置...", this.getModuleName()));return;}this.qrcodeProperties = qrcodeProperties;//属性处理if (CollectionUtils.isEmpty(qrcodeProperties.channels)) {this.channelMap = Maps.newHashMap();} else {this.channelMap = qrcodeProperties.channels.stream().collect(Collectors.toMap(channel -> channel.getType(), Function.identity()));}if (CollectionUtils.isEmpty(qrcodeProperties.bizs)) {this.bizMap = Maps.newHashMap();} else {this.bizMap = qrcodeProperties.bizs.stream().collect(Collectors.toMap(biz -> biz.getType(), Function.identity()));}if (CollectionUtils.isEmpty(qrcodeProperties.getBiz2Channel())) {this.biz2Channel = Maps.newHashMap();} else {this.biz2Channel = qrcodeProperties.getBiz2Channel();}LOGGER.info(String.format("%s 刷新成功..., 当前配置=%s...", this.getModuleName(), this));} catch (Exception e) {LOGGER.error("QrcodeConstants 对象属性绑定失败...", e);}}private void toRefresh() {try {if (isCfgCenterEffect()) {ZookeeperPropertySource propertySource = ConfigHelper.getZookeeperPropertySource();if (ConfigCenterUtils.propertySourceShouldRefresh(this.getModuleName(), propertySource)) {this.refreshQrcodeProperties();}}} catch (Exception e) {LOGGER.error("QrcodeConstants 对象属性刷新失败", e);}}@Overridepublic void refreshForEvent() {this.refreshQrcodeProperties();}@Overridepublic String getDefaultResourcePath() {return "config/qrcode.properties";}@Overridepublic String getConfigPrefix() {return "wx.temporary.qrcode";}@Overridepublic String getModuleName() {return "微信临时二维码配置";}@Overridepublic String toString() {return new ToStringBuilder(this).append("biz2Channel", biz2Channel).append("channelMap", channelMap).append("bizMap", bizMap).toString();}@ConfigurationProperties(prefix = "wx.temporary.qrcode")public static class QrcodeProperties {//渠道private List<Scene> channels;//业务private List<Scene> bizs;//业务和渠道映射关系private Map<String, String> biz2Channel;public List<Scene> getChannels() {return channels;}public void setChannels(List<Scene> channels) {this.channels = channels;}public List<Scene> getBizs() {return bizs;}public void setBizs(List<Scene> bizs) {this.bizs = bizs;}public Map<String, String> getBiz2Channel() {return biz2Channel;}public void setBiz2Channel(Map<String, String> biz2Channel) {this.biz2Channel = biz2Channel;}}public static class Scene {private String type;private String desc;public String getType() {return type;}public void setType(String type) {this.type = type;}public String getDesc() {return desc;}public void setDesc(String desc) {this.desc = desc;}@Overridepublic String toString() {return ReflectionToStringBuilder.toString(this, ToStringStyle.JSON_STYLE, false, false, Scene.class);}} }
方案1和方案2略有不同,针对一些属性,我们需要做一些逻辑处理。方案1中将源属性和逻辑之后的属性都放在了同一类中,方案二则是将源属性单独放到一个静态类中,最终处理过后的属性放在了目标类中。另外二者的doBind方法也是有区别的,仔细看一下BaseConfigCenterBean这个类就可以了。
就先分享这么多了,更多分享请关注我们的技术公众吧!!!
参考文章:算法和技术SHARING