多态的扩展实例

interface Operation
{
	void insert();
	void delete();
}

class JDBC implements Operation
{
	public void insert()
	{
		System.out.println("JDBC的插入");
	}

	public void delete()
	{
		System.out.println("JDBC的删除");
	}
}

class Hebirate implements Operation
{
	public void insert()
	{
		System.out.println("Hebirate的插入");
	}
	public void delete()
	{
		System.out.println("Hebirate的删除。");
	}
}

class  DataBaseOperation
{
	public static void main(String[] args) 
	{
		Operation op=new Hebirate();              //通过接口，当我们更改操作类型时候，直接Operation op=new JDBC();即可，提高扩展性
		op.insert();
		op.delete();
	}
}