Fix injection point with proxied DataSource

Prior to this commit, the `ApplicationContext` couldn't start with a
JDK-proxied `HikariDataSource` as the JMX auto-configuration was
attempting to inject a (too narrowed) `HikariDataSource`.

This commit rather injects a regular `DataSource` and attempt to unwrap
it as a `HikariDataSource`.

Closes gh-12271

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/DataSourceJmxConfiguration.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,23 +48,33 @@ class DataSourceJmxConfiguration {
 
 	@Configuration
 	@ConditionalOnClass(HikariDataSource.class)
-	@ConditionalOnSingleCandidate(HikariDataSource.class)
+	@ConditionalOnSingleCandidate(DataSource.class)
 	static class Hikari {
 
-		private final HikariDataSource dataSource;
+		private final DataSource dataSource;
 
 		private final ObjectProvider<MBeanExporter> mBeanExporter;
 
-		Hikari(HikariDataSource dataSource, ObjectProvider<MBeanExporter> mBeanExporter) {
+		Hikari(DataSource dataSource, ObjectProvider<MBeanExporter> mBeanExporter) {
 			this.dataSource = dataSource;
 			this.mBeanExporter = mBeanExporter;
 		}
 
 		@PostConstruct
 		public void validateMBeans() {
-			MBeanExporter exporter = this.mBeanExporter.getIfUnique();
-			if (exporter != null && this.dataSource.isRegisterMbeans()) {
-				exporter.addExcludedBean("dataSource");
+			HikariDataSource hikariDataSource = unwrapHikariDataSource();
+			if (hikariDataSource != null && hikariDataSource.isRegisterMbeans()) {
+				this.mBeanExporter.ifUnique((exporter) ->
+						exporter.addExcludedBean("dataSource"));
+			}
+		}
+
+		private HikariDataSource unwrapHikariDataSource() {
+			try {
+				return this.dataSource.unwrap(HikariDataSource.class);
+			}
+			catch (SQLException ex) {
+				return null;
 			}
 		}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/jdbc/DataSourceJmxConfigurationTests.java

@@ -31,9 +31,13 @@ import org.apache.tomcat.jdbc.pool.DataSourceProxy;
 import org.apache.tomcat.jdbc.pool.jmx.ConnectionPool;
 import org.junit.Test;
 
+import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -101,6 +105,24 @@ public class DataSourceJmxConfigurationTests {
 		});
 	}
 
+	@Test
+	public void hikariProxiedCanUseRegisterMBeans() {
+		String poolName = UUID.randomUUID().toString();
+		this.contextRunner.withUserConfiguration(DataSourceProxyConfiguration.class)
+				.withPropertyValues(
+						"spring.datasource.type=" + HikariDataSource.class.getName(),
+						"spring.datasource.name=" + poolName,
+						"spring.datasource.hikari.register-mbeans=true")
+				.run((context) -> {
+					assertThat(context).hasSingleBean(javax.sql.DataSource.class);
+					HikariDataSource hikariDataSource = context.getBean(
+							javax.sql.DataSource.class).unwrap(HikariDataSource.class);
+					assertThat(hikariDataSource.isRegisterMbeans()).isTrue();
+					MBeanServer mBeanServer = context.getBean(MBeanServer.class);
+					validateHikariMBeansRegistration(mBeanServer, poolName, true);
+				});
+	}
+
 	private void validateHikariMBeansRegistration(MBeanServer mBeanServer,
 			String poolName, boolean expected) throws MalformedObjectNameException {
 		assertThat(mBeanServer.isRegistered(
@@ -130,4 +152,31 @@ public class DataSourceJmxConfigurationTests {
 		});
 	}
 
+	@Configuration
+	static class DataSourceProxyConfiguration {
+
+		@Bean
+		public static DataSourceBeanPostProcessor dataSourceBeanPostProcessor() {
+			return new DataSourceBeanPostProcessor();
+		}
+
+	}
+
+
+	private static class DataSourceBeanPostProcessor implements BeanPostProcessor {
+
+		@Override
+		public Object postProcessAfterInitialization(Object bean, String beanName) {
+			if (bean instanceof javax.sql.DataSource) {
+				return wrap((javax.sql.DataSource) bean);
+			}
+			return bean;
+		}
+
+		private static javax.sql.DataSource wrap(javax.sql.DataSource dataSource) {
+			return (javax.sql.DataSource) new ProxyFactory(dataSource).getProxy();
+		}
+
+	}
+
 }