code: public static Object instance(String clsName,ClassLoader loader)
  	{
  		try
  		{
  			return Class.forName(clsName,true,loader).newInstance();
  		}
  		catch (InstantiationException e)
  		{
  			throw new RuntimeException(e);
  		}
  		catch (IllegalAccessException e)
  		{
  			throw new RuntimeException(e);
  		}
  		catch (ClassNotFoundException e)
  		{
  			throw new RuntimeException(e);
  		}
  	}
docs: 针对Class.forName(clsname).newInstance()的一个简单封装
  @param clsName
  @return 如果未能创建实例，则抛出runtime异常