words = words==null?"":words; java语言,

words = words==null?"":words; java语言,
words = words==null?"":words; java语言,

words = words==null?"":words; java语言,
这是三元表达式,类似于 if else . ? 表示真,: 表示假
等同于下面：
if (words == null) {
words = "";
}else{
words = words;
}