SpringBoot项目实现配置实时刷新功能
Posted jun1019
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需求描述：在SpringBoot项目中，一般业务配置都是写死在配置文件中的，如果某个业务配置想修改，就得重启项目。这在生产环境是不被允许的，这就需要通过技术手段做到配置变更后即使生效。下面就来看一下怎么实现这个功能。
来一张核心代码截图：
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实现思路：
我们知道Spring提供了@Value注解来获取配置文件中的配置项，我们也可以自己定义一个注解来模仿Spring的这种获取配置的方式，
只不过@Value获取的是静态的配置，而我们的注解要实现配置能实时刷新。比如我使用@DynamicConf("$key")来引用配置，在SpringBoot工程启动的时候，
就扫描项目中所有使用了该注解的Bean属性，将配置信息从数据库中读取出来放到本地缓存，然后挨个赋值给加了@DynamicConf注解的属性。
当配置有变更时，就动态给这个属性重新赋值。这就是最核心的思路，下面看如何用代码实现。
1.创建一张数据表，用于存储配置信息：
CREATE TABLE `s_system_dict` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT ‘自增主键，唯一标识‘, `dict_name` varchar(64) NOT NULL COMMENT ‘字典名称‘, `dict_key` varchar(255) NOT NULL COMMENT ‘字典KEY‘, `dict_value` varchar(2000) NOT NULL COMMENT ‘字典VALUE‘, `dict_type` int(11) NOT NULL DEFAULT ‘0‘ COMMENT ‘字典类型 0系统配置 1微信配置 2支付宝配置 3推送 4短信 5版本‘, `dict_desc` varchar(255) NOT NULL DEFAULT ‘‘ COMMENT ‘字典描述‘, `status` int(4) NOT NULL DEFAULT ‘1‘ COMMENT ‘字典状态：0-停用 1-正常‘, `delete_flag` tinyint(1) NOT NULL DEFAULT ‘0‘ COMMENT ‘是否删除：0-未删除 1-已删除‘, `operator` int(11) NOT NULL COMMENT ‘操作人ID，关联用户域用户表ID‘, `create_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘创建时间‘, `update_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT ‘修改时间‘, `delete_time` datetime NOT NULL DEFAULT ‘1970-01-01 00:00:00‘ COMMENT ‘删除时间‘, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=47 DEFAULT CHARSET=utf8 COMMENT=‘配置字典表‘;
2.自定义注解
import java.lang.annotation.*; @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface DynamicConf String value(); String defaultValue() default ""; boolean callback() default true;
3.配置变更接口
public interface DynamicConfListener void onChange(String key, String value) throws Exception;
4.配置变更实现：
public class BeanRefreshDynamicConfListener implements DynamicConfListener public static class BeanField private String beanName; private String property; public BeanField() public BeanField(String beanName, String property) this.beanName = beanName; this.property = property; public String getBeanName() return beanName; public void setBeanName(String beanName) this.beanName = beanName; public String getProperty() return property; public void setProperty(String property) this.property = property; private static Map<String, List<BeanField>> key2BeanField = new ConcurrentHashMap<>(); public static void addBeanField(String key, BeanField beanField) List<BeanField> beanFieldList = key2BeanField.get(key); if (beanFieldList == null) beanFieldList = new ArrayList<>(); key2BeanField.put(key, beanFieldList); for (BeanField item : beanFieldList) if (item.getBeanName().equals(beanField.getBeanName()) && item.getProperty().equals(beanField.getProperty())) return; // avoid repeat refresh beanFieldList.add(beanField); /** * refresh bean field * * @param key * @param value * @throws Exception */ @Override public void onChange(String key, String value) throws Exception List<BeanField> beanFieldList = key2BeanField.get(key); if (beanFieldList != null && beanFieldList.size() > 0) for (BeanField beanField : beanFieldList) DynamicConfFactory.refreshBeanField(beanField, value, null);
5.用一个工程包装一下
public class DynamicConfListenerFactory /** * dynamic config listener repository */ private static List<DynamicConfListener> confListenerRepository = Collections.synchronizedList(new ArrayList<>()); /** * add listener * * @param confListener * @return */ public static boolean addListener(DynamicConfListener confListener) if (confListener == null) return false; confListenerRepository.add(confListener); return true; /** * refresh bean field * * @param key * @param value */ public static void onChange(String key, String value) if (key == null || key.trim().length() == 0) return; if (confListenerRepository.size() > 0) for (DynamicConfListener confListener : confListenerRepository) try confListener.onChange(key, value); catch (Exception e) log.error(">>>>>>>>>>> refresh bean field, key=, value=, exception=", key, value, e);
6.对Spring的扩展，实现实时刷新功能最核心的部分
public class DynamicConfFactory extends InstantiationAwareBeanPostProcessorAdapter implements InitializingBean, DisposableBean, BeanNameAware, BeanFactoryAware
// 注入操作配置信息的业务类 @Autowired private SystemDictService systemDictService; @Override public void afterPropertiesSet() DynamicConfBaseFactory.init();
// 启动时将数据库中的配置缓存到本地（用一个Map存） LocalDictMap.setDictMap(systemDictService.all()); @Override public void destroy() DynamicConfBaseFactory.destroy(); @Override public boolean postProcessAfterInstantiation(final Object bean, final String beanName) throws BeansException if (!beanName.equals(this.beanName)) ReflectionUtils.doWithFields(bean.getClass(), field -> if (field.isAnnotationPresent(DynamicConf.class)) String propertyName = field.getName(); DynamicConf dynamicConf = field.getAnnotation(DynamicConf.class); String confKey = dynamicConf.value(); confKey = confKeyParse(confKey);
// 从本地缓存中获取配置 String confValue = LocalDictMap.getDict(confKey); confValue = !StringUtils.isEmpty(confValue) ? confValue : ""; BeanRefreshDynamicConfListener.BeanField beanField = new BeanRefreshDynamicConfListener.BeanField(beanName, propertyName); refreshBeanField(beanField, confValue, bean); if (dynamicConf.callback()) BeanRefreshDynamicConfListener.addBeanField(confKey, beanField); ); return super.postProcessAfterInstantiation(bean, beanName); public static void refreshBeanField(final BeanRefreshDynamicConfListener.BeanField beanField, final String value, Object bean) if (bean == null) try
// 如果你的项目使用了Aop，比如AspectJ，那么有些Bean可能会被代理，
// 这里你获取到的可能就不是真实的Bean而是被代理后的Bean，所以这里获取真实的Bean; bean = AopTargetUtils.getTarget(DynamicConfFactory.beanFactory.getBean(beanField.getBeanName())); catch (Exception e) log.error(">>>>>>>>>>>> Get target bean fail!!!!!"); if (bean == null) return; BeanWrapper beanWrapper = new BeanWrapperImpl(bean); PropertyDescriptor propertyDescriptor = null; PropertyDescriptor[] propertyDescriptors = beanWrapper.getPropertyDescriptors(); if (propertyDescriptors != null && propertyDescriptors.length > 0) for (PropertyDescriptor item : propertyDescriptors) if (beanField.getProperty().equals(item.getName())) propertyDescriptor = item; if (propertyDescriptor != null && propertyDescriptor.getWriteMethod() != null) beanWrapper.setPropertyValue(beanField.getProperty(), value); log.info(">>>>>>>>>>> refresh bean field[set] success, #=", beanField.getBeanName(), beanField.getProperty(), value); else final Object finalBean = bean; ReflectionUtils.doWithFields(bean.getClass(), fieldItem -> if (beanField.getProperty().equals(fieldItem.getName())) try Object valueObj = FieldReflectionUtil.parseValue(fieldItem.getType(), value); fieldItem.setAccessible(true); fieldItem.set(finalBean, valueObj); log.info(">>>>>>>>>>> refresh bean field[field] success, #=", beanField.getBeanName(), beanField.getProperty(), value); catch (IllegalAccessException e) throw new RuntimeException(">>>>>>>>>>> refresh bean field[field] fail, " + beanField.getBeanName() + "#" + beanField.getProperty() + "=" + value); ); private static final String placeholderPrefix = "$"; private static final String placeholderSuffix = ""; /** * valid placeholder * * @param originKey * @return */ private static boolean confKeyValid(String originKey) if (originKey == null || "".equals(originKey.trim())) throw new RuntimeException(">>>>>>>>>>> originKey[" + originKey + "] not be empty"); boolean start = originKey.startsWith(placeholderPrefix); boolean end = originKey.endsWith(placeholderSuffix); return start && end ? true : false; /** * parse placeholder * * @param originKey * @return */ private static String confKeyParse(String originKey) if (confKeyValid(originKey)) return originKey.substring(placeholderPrefix.length(), originKey.length() - placeholderSuffix.length()); return originKey; private String beanName; @Override public void setBeanName(String name) this.beanName = name; private static BeanFactory beanFactory; @Override public void setBeanFactory(BeanFactory beanFactory) throws BeansException this.beanFactory = beanFactory;
7.配置Bean
@Configuration public class DynamicConfConfig @Bean public DynamicConfFactory dynamicConfFactory() DynamicConfFactory dynamicConfFactory = new DynamicConfFactory(); return dynamicConfFactory;
8.使用方式
@RestController @RequestMapping("/test") public class TestController @DynamicConf("$test.dynamic.config.key") private String testDynamicConfig; @GetMapping("/getConfig") public JSONObject testDynamicConfig(String key)
// 从本地缓存获取配置(就是一个Map) String value = LocalDictMap.getDict(key); JSONObject json = new JSONObject(); json.put(key, value); return json;
// 通过接口来修改数据库中的配置信息 @GetMapping("/updateConfig") public String updateConfig(String key, String value) SystemDictDto dictDto = new SystemDictDto(); dictDto.setDictKey(key); dictDto.setDictValue(value); systemDictService.update(dictDto, 0); return "success";
9.配置变更后刷新
// 刷新Bean属性
DynamicConfListenerFactory.onChange(dictKey, dictValue);
// TODO 刷新本地缓存 略
10.补上一个工具类）
public class AopTargetUtils /** * 获取目标对象 * * @param proxy 代理对象 * @return 目标对象 * @throws Exception */ public static Object getTarget(Object proxy) throws Exception if (!AopUtils.isAopProxy(proxy)) return proxy; if (AopUtils.isJdkDynamicProxy(proxy)) proxy = getJdkDynamicProxyTargetObject(proxy); else proxy = getCglibProxyTargetObject(proxy); return getTarget(proxy); private static Object getCglibProxyTargetObject(Object proxy) throws Exception Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0"); h.setAccessible(true); Object dynamicAdvisedInterceptor = h.get(proxy); Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised"); advised.setAccessible(true); Object target = ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget(); return target; private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception Field h = proxy.getClass().getSuperclass().getDeclaredField("h"); h.setAccessible(true); AopProxy aopProxy = (AopProxy) h.get(proxy); Field advised = aopProxy.getClass().getDeclaredField("advised"); advised.setAccessible(true); Object target = ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget(); return target;
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