麻煩大神找一下錯誤、在更新信息時會出現(xiàn)空指針異常~~~(問題已解決- -!!)
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(chuàng)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("www.xiaobai@163.com"); 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(xiàn)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)
2016-01-06
你在action辛辛苦苦創(chuàng)一個對象,傳到dao,然后再把它設置為空,對象里的東西都沒了,更新時空指針了