[Java] Class.forName(String className) 그리고 Service Provider Interface

1.java

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection conn = null;
conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORA92", "scott", "tiger");
Statement..

2.java

package serviceprovider;

public interface Connection {

}


//
package serviceprovider;

public interface Driver {
	Connection getConnection();
}

3.java

package serviceprovider;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class DriverManager {
	private DriverManager() {}
	
	private static final Map<String,Driver> drivers = new ConcurrentHashMap<String,Driver>();
	public static final String DEFAULT_DRIVER_NAME = "default";
	
	public static void registerDefaultPrivider(Driver d) {
                System.out.println("Driver 등록");
		registerDriver(DEFAULT_DRIVER_NAME, d);
	}
	
	public static void registerDriver(String name, Driver d) {
		drivers.put(name,d);
	}
	
	public static Connection getConnection() {
		return getConnection(DEFAULT_DRIVER_NAME);
	}
	
	public static Connection getConnection(String name) {
		Driver d = drivers.get(name);
		if(d==null) 
			throw new IllegalArgumentException();
	 return d.getConnection();
	}
}
//Effective Java SE P11 참고

4.java

static 
    {
        defaultDriver = null;
        Timestamp timestamp = Timestamp.valueOf("2000-01-01 00:00:00.0");
        try
        {
            if(defaultDriver == null)
            {
                defaultDriver = new OracleDriver();
                DriverManager.registerDriver(defaultDriver);
            }
        }
        catch(RuntimeException runtimeexception) { }
        catch(SQLException sqlexception) { }
    }

5.java

package serviceprovider;
public class MyDriver implements Driver {
	private Log logger = LogFactory.getLog(MyDriver.class);
	
	private static Driver defaultDriver;
	static {
		defaultDriver = new MyDriver();
		serviceprovider.DriverManager.registerDefaultPrivider(defaultDriver);
	}
	
	@Override
	public Connection getConnection() {
		System.out.println("MyDriver's Connection return");
		return null;
	}
}

6.java

package serviceprovider;
public class Test {
	private Log logger = LogFactory.getLog(Test.class);
	
	public static void main(String[] args) throws ClassNotFoundException {
		Class.forName("MyDriver");
		Connection connection = DriverManager.getConnection();
	}
}