feat: 添加多数据源切换拦截器。

mybatis-flex-spring/src/main/java/com/mybatisflex/spring/datasource/DataSourceInterceptor.java

@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
+ *  <p>
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *  <p>
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *  <p>
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package com.mybatisflex.spring.datasource;
+
+
+import com.mybatisflex.annotation.UseDataSource;
+import com.mybatisflex.core.datasource.DataSourceKey;
+import org.aopalliance.intercept.MethodInterceptor;
+import org.aopalliance.intercept.MethodInvocation;
+
+/**
+ * 多数据源切换拦截器。
+ *
+ * @author 王帅
+ * @since 2023-06-25
+ */
+public class DataSourceInterceptor implements MethodInterceptor {
+
+    @Override
+    public Object invoke(MethodInvocation invocation) throws Throwable {
+        String dsKey = determineDataSourceKey(invocation);
+        DataSourceKey.use(dsKey);
+        try {
+            return invocation.proceed();
+        } finally {
+            DataSourceKey.clear();
+        }
+    }
+
+    private String determineDataSourceKey(MethodInvocation invocation) {
+        UseDataSource annotation;
+
+        Object aThis = invocation.getThis();
+
+        if (aThis != null) {
+            // 类上定义有 UseDataSource 注解
+            Class<?> aClass = aThis.getClass();
+            annotation = aClass.getAnnotation(UseDataSource.class);
+            if (annotation != null) {
+                return annotation.value();
+            }
+        }
+
+        // 方法上定义有 UseDataSource 注解
+        annotation = invocation.getMethod().getAnnotation(UseDataSource.class);
+        if (annotation != null) {
+            return annotation.value();
+        }
+
+        // 没有的话使用当前数据源
+        return DataSourceKey.get();
+    }
+
+}