public?void?updateGoddess(Goddess?g)?{
		Connection?conn?=?DBUtil.getConnection();
		String?sql?=?""?+?"update?imooc_goddess?"
				+?"?set?user_name=?,sex=?,age=?,birthday=?,email=?,mobile=?,"
				+?"?update_user=?,update_date=current_date(),isdel=??"
				+?"?where?id=?";
		try?{
			//?預編譯SQL
			PreparedStatement?pst?=?conn.prepareStatement(sql);
			//g?=?new?Goddess();??此處不能創建新的對象(問題根源)

			pst.setString(1,?g.getUser_name());
			pst.setInt(2,?g.getSex());
			pst.setInt(3,?g.getAge());
			pst.setDate(4,?new?Date(g.getBirthday().getTime()));
			pst.setString(5,?g.getEmail());
			pst.setString(6,?g.getMobile());
			pst.setString(7,?g.getUpdate_user());
			pst.setInt(8,?g.getIsdel());
			pst.setInt(9,?g.getId());

			pst.execute();
		}?catch?(SQLException?e)?{
			//?TODO?Auto-generated?catch?block
			e.printStackTrace();
		}
	}

public?class?GoddessAction?{

	public?static?void?main(String[]?args)?{
		GoddessDao?g?=?new?GoddessDao();
//		List<Goddess>?gList?=?g.query();
//		for?(Goddess?goddess?:?gList)?{
//			System.out.println(goddess.getUser_name()?+?","?+?goddess.getSex()
//					+?","?+?goddess.getAge()?+?","?+?goddess.getBirthday());
//		}
		
		Goddess?g1?=?new?Goddess();
		g1.setUser_name("小美");
		g1.setSex(1);
		g1.setAge(20);
		g1.setBirthday(new?Date());
		g1.setEmail("[email protected]");
		g1.setMobile("18812341234");
		g1.setCreate_user("localhost");
		g1.setUpdate_user("localhost");
		g1.setIsdel(1);
		g1.setId(3);
		g.updateGoddess(g1);
	}

}

在更新birthday時出現空指針異常

Exception?in?thread?"main"?java.lang.NullPointerException
	at?com.imooc.dao.GoddessDao.updateGoddess(GoddessDao.java:73)
	at?com.imooc.action.GoddessAction.main(GoddessAction.java:39)