Question

)刚开始学java写了个小程序，一直报错找了半天也不知道什么问题，请高手指点？

java.lang.NullPointerException
com.dao.imp.UsersDao.check(UsersDao.java:100)
com.biz.imp.UsersBiz.check(UsersBiz.java:38)
com.action.imp.UsersAction.check(UsersAction.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
public Users check(Users us) {

String sql="select * from users where uname=? and passwd=?";
rst=DBHelper.executeQuery(sql, new String[]{
us.getUname(),us.getPasswd()
});
try {
if(rst.next()){
us=new Users(rst.getString(1), rst.getString(2), rst.getString(3), rst.getString(4), rst.getString(5), rst.getString(6), rst.getString(7), rst.getString(8));
return us;
}

Answer 1

UsersDao.java:100 空指针异常 ， 在check方法里打断点 调试一下