📅  最后修改于: 2022-03-11 14:52:26.963000             🧑  作者: Mango
if(str != null && !str.isEmpty())
Be sure to use the parts of && in this order, because java will not proceed to evaluate the second part if the first part of && fails, thus ensuring you will not get a null pointer exception from str.isEmpty() if str is null.