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) {// NOSONAR
String 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;
}
@Override
public 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;
}
@Subscribe
public 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));//NOSONAR
private 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 proxies
enhancer.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 {
@Override
public 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;
}
@Override
public 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
@ConfigField
private List<Scene> bizs;
//业务和渠道映射关系
@ConfigField
private 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;
}
@ToInitial
private 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
@Override
public void refreshForEvent() {
this.refreshQrcodeProperties();
}
//本地资源文件
@Override
public String getDefaultResourcePath() {
return "config/qrcode.properties";
}
//属性配置 公共前缀（和@ConfigurationProperties prefix 属性一致）
@Override
public String getConfigPrefix() {
return "wx.temporary.qrcode";
}
//模块名称
@Override
public String getModuleName() {
return "微信临时二维码配置";
}
@Override
public 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;
}
@Override
public 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;
}
@ToInitial
private 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);
}
}
@Override
public void refreshForEvent() {
this.refreshQrcodeProperties();
}
@Override
public String getDefaultResourcePath() {
return "config/qrcode.properties";
}
@Override
public String getConfigPrefix() {
return "wx.temporary.qrcode";
}
@Override
public String getModuleName() {
return "微信临时二维码配置";
}
@Override
public 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;
}
@Override
public 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。
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参考文章：算法和技术SHARING
原文地址：https://www.cnblogs.com/hujunzheng/p/9697282.html
时间： 2024-09-30 23:22:29