Fix #288 allow explicit definition of driverClassName to override DriverManager.getDriver(url) located driver.

hikaricp-common/src/main/java/com/zaxxer/hikari/AbstractHikariConfig.java

@@ -354,6 +354,11 @@ public abstract class AbstractHikariConfig implements HikariConfigMBean
       dataSourceProperties.putAll(dsProperties);
    }
 
+   public String getDriverClassName()
+   {
+      return driverClassName;
+   }
+
    public void setDriverClassName(String driverClassName)
    {
       try {

hikaricp-common/src/main/java/com/zaxxer/hikari/pool/BaseHikariPool.java

@@ -150,7 +150,7 @@ public abstract class BaseHikariPool implements HikariPoolMBean, IBagStateListen
       setMetricRegistry(configuration.getMetricRegistry());
       setHealthCheckRegistry(configuration.getHealthCheckRegistry());
 
-      this.dataSource = poolUtils.initializeDataSource(configuration.getDataSourceClassName(), configuration.getDataSource(), configuration.getDataSourceProperties(), configuration.getJdbcUrl(), username, password);
+      this.dataSource = poolUtils.initializeDataSource(configuration.getDataSourceClassName(), configuration.getDataSource(), configuration.getDataSourceProperties(), configuration.getDriverClassName(), configuration.getJdbcUrl(), username, password);
 
       this.addConnectionExecutor = createThreadPoolExecutor(configuration.getMaximumPoolSize(), "HikariCP connection filler (pool " + configuration.getPoolName() + ")", configuration.getThreadFactory(), new ThreadPoolExecutor.DiscardPolicy());
       this.closeConnectionExecutor = createThreadPoolExecutor(4, "HikariCP connection closer (pool " + configuration.getPoolName() + ")", configuration.getThreadFactory(), new ThreadPoolExecutor.CallerRunsPolicy());

hikaricp-common/src/main/java/com/zaxxer/hikari/pool/PoolUtilities.java

@@ -90,12 +90,13 @@ public final class PoolUtilities
     * @param dsClassName a DataSource class name (optional)
     * @param dataSource a DataSource instance (optional)
     * @param dataSourceProperties a Properties instance of DataSource properties
+    * @param driverClassName the JDBC driver class name (optional)
     * @param jdbcUrl a JDBC connection URL (optional)
     * @param username a username (optional)
     * @param password a password (optional)
     * @return a DataSource instance
     */
-   public DataSource initializeDataSource(final String dsClassName, DataSource dataSource, final Properties dataSourceProperties, final String jdbcUrl, final String username, final String password)
+   public DataSource initializeDataSource(final String dsClassName, DataSource dataSource, final Properties dataSourceProperties, final String driverClassName, final String jdbcUrl, final String username, final String password)
    {
       try {
          if (dataSource == null && dsClassName != null) {
@@ -104,7 +105,7 @@ public final class PoolUtilities
             return dataSource;
          }
          else if (jdbcUrl != null) {
-            return new DriverDataSource(jdbcUrl, dataSourceProperties, username, password);
+            return new DriverDataSource(jdbcUrl, driverClassName, dataSourceProperties, username, password);
          }
    
          return dataSource;

hikaricp-common/src/main/java/com/zaxxer/hikari/util/DriverDataSource.java

@@ -21,6 +21,7 @@ import java.sql.Driver;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.SQLFeatureNotSupportedException;
+import java.util.Enumeration;
 import java.util.Map.Entry;
 import java.util.Properties;
 
@@ -32,7 +33,7 @@ public final class DriverDataSource implements DataSource
    private final Properties driverProperties;
    private final Driver driver;
 
-   public DriverDataSource(String jdbcUrl, Properties properties, String username, String password)
+   public DriverDataSource(String jdbcUrl, String driverClassName, Properties properties, String username, String password)
    {
       try {
          this.jdbcUrl = jdbcUrl;
@@ -49,7 +50,27 @@ public final class DriverDataSource implements DataSource
             driverProperties.put("password", driverProperties.getProperty("password", password));
          }
 
-         driver = DriverManager.getDriver(jdbcUrl);
+         if (driverClassName != null) {
+            Driver matched = null;
+            Enumeration<Driver> drivers = DriverManager.getDrivers();
+            while (drivers.hasMoreElements()) {
+               Driver d = drivers.nextElement();
+               if (d.getClass().getName().equals(driverClassName)) {
+                  matched = d;
+                  break;
+               }
+            }
+
+            if (matched != null) {
+               driver = matched;
+            }
+            else {
+               throw new IllegalArgumentException("Driver with class name " + driverClassName + " was not found among registered drivers");
+            }
+         }
+         else {
+            driver = DriverManager.getDriver(jdbcUrl);
+         }
       }
       catch (SQLException e) {
          throw new RuntimeException("Unable to get driver for JDBC URL " + jdbcUrl, e);