From eee7628986c3eedd92d6673c61710a103607e2ae Mon Sep 17 00:00:00 2001
From: "chen.ma" <machencoding@163.com>
Date: Wed, 5 Jan 2022 22:55:33 +0800
Subject: [PATCH] =?UTF-8?q?ListableBeanFactory#findAnnotationOnBean=20Spri?=
 =?UTF-8?q?ngBoot=20=E4=BD=8E=E7=89=88=E6=9C=AC=E9=80=82=E9=85=8D.=20(#64)?=
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---
 .../core/DynamicThreadPoolPostProcessor.java  | 22 +++++++--
 .../DynamicThreadPoolAnnotationUtil.java      | 47 +++++++++++++++++++
 2 files changed, 65 insertions(+), 4 deletions(-)
 create mode 100644 hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/toolkit/DynamicThreadPoolAnnotationUtil.java

diff --git a/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/core/DynamicThreadPoolPostProcessor.java b/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/core/DynamicThreadPoolPostProcessor.java
index 2303dc5a..3315cd47 100644
--- a/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/core/DynamicThreadPoolPostProcessor.java
+++ b/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/core/DynamicThreadPoolPostProcessor.java
@@ -9,6 +9,7 @@ import cn.hippo4j.common.web.base.Result;
 import cn.hippo4j.starter.common.CommonDynamicThreadPool;
 import cn.hippo4j.starter.config.BootstrapProperties;
 import cn.hippo4j.starter.remote.HttpAgent;
+import cn.hippo4j.starter.toolkit.DynamicThreadPoolAnnotationUtil;
 import cn.hippo4j.starter.toolkit.thread.QueueTypeEnum;
 import cn.hippo4j.starter.toolkit.thread.RejectedTypeEnum;
 import cn.hippo4j.starter.toolkit.thread.ThreadPoolBuilder;
@@ -60,16 +61,29 @@ public final class DynamicThreadPoolPostProcessor implements BeanPostProcessor {
     @Override
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
         if (bean instanceof DynamicThreadPoolExecutor) {
-            DynamicThreadPool dynamicThreadPool = ApplicationContextHolder.findAnnotationOnBean(beanName, DynamicThreadPool.class);
-            if (Objects.isNull(dynamicThreadPool)) {
-                return bean;
+            DynamicThreadPool dynamicThreadPool;
+            try {
+                dynamicThreadPool = ApplicationContextHolder.findAnnotationOnBean(beanName, DynamicThreadPool.class);
+                if (Objects.isNull(dynamicThreadPool)) {
+                    // 适配低版本 SpringBoot
+                    dynamicThreadPool = DynamicThreadPoolAnnotationUtil.findAnnotationOnBean(beanName, DynamicThreadPool.class);
+                    if (Objects.isNull(dynamicThreadPool)) {
+                        return bean;
+                    }
+                }
+            } catch (Exception ex) {
+                log.error("Failed to create dynamic thread pool in annotation mode.", ex);
             }
+
             DynamicThreadPoolExecutor dynamicExecutor = (DynamicThreadPoolExecutor) bean;
             DynamicThreadPoolWrapper wrap = new DynamicThreadPoolWrapper(dynamicExecutor.getThreadPoolId(), dynamicExecutor);
             ThreadPoolExecutor remoteExecutor = fillPoolAndRegister(wrap);
             subscribeConfig(wrap);
+
             return remoteExecutor;
-        } else if (bean instanceof DynamicThreadPoolWrapper) {
+        }
+
+        if (bean instanceof DynamicThreadPoolWrapper) {
             DynamicThreadPoolWrapper wrap = (DynamicThreadPoolWrapper) bean;
             registerAndSubscribe(wrap);
         }
diff --git a/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/toolkit/DynamicThreadPoolAnnotationUtil.java b/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/toolkit/DynamicThreadPoolAnnotationUtil.java
new file mode 100644
index 00000000..126e2783
--- /dev/null
+++ b/hippo4j-spring-boot-starter/src/main/java/cn/hippo4j/starter/toolkit/DynamicThreadPoolAnnotationUtil.java
@@ -0,0 +1,47 @@
+package cn.hippo4j.starter.toolkit;
+
+import cn.hippo4j.common.config.ApplicationContextHolder;
+import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.context.support.AbstractApplicationContext;
+import org.springframework.core.annotation.AnnotationUtils;
+
+import java.lang.annotation.Annotation;
+import java.util.Optional;
+
+/**
+ * {@link DynamicThreadPoolAnnotationUtil} 是为了适配低版本 SpringBoot.
+ *
+ * <p>Spring version >= 5.2.0 下述方法才是有效的, 等同于 SpringBoot version 2.2.0.RELEASE
+ * {@link ListableBeanFactory#findAnnotationOnBean(java.lang.String, java.lang.Class)}
+ *
+ * <p>但这不是一个优雅的实现方式, 因为其中用到了很多强类型转换, 不确定后续 Spring 升级是否会受影响.
+ * 不过, 可以确定的是 Spring version < 5.3.14 是没问题的, 等同于 SpringBoot version < 2.6.2
+ *
+ * @author chen.ma
+ * @date 2022/1/5 21:15
+ */
+public class DynamicThreadPoolAnnotationUtil {
+
+    /**
+     * 根据 {@param beanName} 查询注解 {@param annotationType} 是否存在.
+     *
+     * @param beanName
+     * @param annotationType
+     * @param <A>
+     * @return
+     */
+    public static <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType) {
+        AbstractApplicationContext context = (AbstractApplicationContext) ApplicationContextHolder.getInstance();
+        ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
+        A annotation = Optional.ofNullable(beanFactory)
+                .map(each -> (RootBeanDefinition) beanFactory.getMergedBeanDefinition(beanName))
+                .map(definition -> definition.getResolvedFactoryMethod())
+                .map(factoryMethod -> AnnotationUtils.getAnnotation(factoryMethod, annotationType))
+                .orElse(null);
+
+        return annotation;
+    }
+
+}