Fix order of connection pools in DataSourceBuilder

Closes gh-6013

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

@@ -33,8 +33,8 @@ import org.springframework.util.ClassUtils;
 
 /**
  * Convenience class for building a {@link DataSource} with common implementations and
- * properties. If Tomcat, HikariCP or Commons DBCP are on the classpath one of them will
- * be selected (in that order with Tomcat first). In the interest of a uniform interface,
+ * properties. If HikariCP, Tomcat or Commons DBCP are on the classpath one of them will
+ * be selected (in that order with Hikari first). In the interest of a uniform interface,
  * and so that there can be a fallback to an embedded database if one can be detected on
  * the classpath, only a small set of common configuration properties are supported. To
  * inject additional properties into the result you can downcast it, or use
@@ -47,8 +47,8 @@ import org.springframework.util.ClassUtils;
 public class DataSourceBuilder {
 
 	private static final String[] DATA_SOURCE_TYPE_NAMES = new String[] {
-			"org.apache.tomcat.jdbc.pool.DataSource",
 			"com.zaxxer.hikari.HikariDataSource",
+			"org.apache.tomcat.jdbc.pool.DataSource",
 			"org.apache.commons.dbcp2.BasicDataSource" };
 
 	private Class<? extends DataSource> type;

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

@@ -16,8 +16,6 @@
 
 package org.springframework.boot.autoconfigure.jdbc;
 
-import java.net.URL;
-import java.net.URLClassLoader;
 import java.sql.Connection;
 import java.sql.Driver;
 import java.sql.DriverPropertyInfo;
@@ -303,26 +301,4 @@ public class DataSourceAutoConfigurationTests {
 
 	}
 
-	private static final class HidePackagesClassLoader extends URLClassLoader {
-
-		private final String[] hiddenPackages;
-
-		private HidePackagesClassLoader(String... hiddenPackages) {
-			super(new URL[0], DataSourceAutoConfigurationTests.class.getClassLoader());
-			this.hiddenPackages = hiddenPackages;
-		}
-
-		@Override
-		protected Class<?> loadClass(String name, boolean resolve)
-				throws ClassNotFoundException {
-			for (String hiddenPackage : this.hiddenPackages) {
-				if (name.startsWith(hiddenPackage)) {
-					throw new ClassNotFoundException();
-				}
-			}
-			return super.loadClass(name, resolve);
-		}
-
-	}
-
 }

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

+/*
+ * Copyright 2012-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.springframework.boot.autoconfigure.jdbc;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+import javax.sql.DataSource;
+
+import com.zaxxer.hikari.HikariDataSource;
+import org.apache.commons.dbcp2.BasicDataSource;
+import org.junit.After;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link DataSourceBuilder}.
+ *
+ * @author Stephane Nicoll
+ */
+public class DataSourceBuilderTests {
+
+	private DataSource dataSource;
+
+	@After
+	public void shutdownDataSource() throws IOException {
+		if (this.dataSource instanceof Closeable) {
+			((Closeable) this.dataSource).close();
+		}
+	}
+
+	@Test
+	public void defaultToHikari() {
+		this.dataSource = DataSourceBuilder.create()
+				.url("jdbc:h2:test").build();
+		assertThat(this.dataSource).isInstanceOf(HikariDataSource.class);
+	}
+
+	@Test
+	public void defaultToTomcatIfHikariIsNotAvailable() {
+		this.dataSource = DataSourceBuilder.create(
+				new HidePackagesClassLoader("com.zaxxer.hikari"))
+				.url("jdbc:h2:test").build();
+		assertThat(this.dataSource).isInstanceOf(
+				org.apache.tomcat.jdbc.pool.DataSource.class);
+	}
+
+	@Test
+	public void defaultToCommonsDbcp2AsLastResort() {
+		this.dataSource = DataSourceBuilder.create(
+				new HidePackagesClassLoader("com.zaxxer.hikari",
+						"org.apache.tomcat.jdbc.pool"))
+				.url("jdbc:h2:test").build();
+		assertThat(this.dataSource).isInstanceOf(BasicDataSource.class);
+	}
+
+}

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

@@ -95,9 +95,7 @@ public class DataSourceInitializerTests {
 	public void testTwoDataSources() throws Exception {
 		EnvironmentTestUtils.addEnvironment(this.context,
 				"datasource.one.url=jdbc:hsqldb:mem:/one",
-				"datasource.one.driverClassName=org.hsqldb.Driver",
-				"datasource.two.url=jdbc:hsqldb:mem:/two",
-				"datasource.two.driverClassName=org.hsqldb.Driver");
+				"datasource.two.url=jdbc:hsqldb:mem:/two");
 		this.context.register(TwoDataSources.class, DataSourceInitializer.class,
 				PropertyPlaceholderAutoConfiguration.class, DataSourceProperties.class);
 		this.context.refresh();

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

+/*
+ * Copyright 2012-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.springframework.boot.autoconfigure.jdbc;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * Test {@link URLClassLoader} that hides configurable packages.
+ *
+ * @author Andy Wilkinson
+ * @author Stephane Nicoll
+ */
+final class HidePackagesClassLoader extends URLClassLoader {
+
+	private final String[] hiddenPackages;
+
+	HidePackagesClassLoader(String... hiddenPackages) {
+		super(new URL[0], HidePackagesClassLoader.class.getClassLoader());
+		this.hiddenPackages = hiddenPackages;
+	}
+
+	@Override
+	protected Class<?> loadClass(String name, boolean resolve)
+			throws ClassNotFoundException {
+		for (String hiddenPackage : this.hiddenPackages) {
+			if (name.startsWith(hiddenPackage)) {
+				throw new ClassNotFoundException();
+			}
+		}
+		return super.loadClass(name, resolve);
+	}
+
+}