字符串空白（空或空）检查：如果结构与 java 8 可选/过滤器

Question

Question : Which approach is better and why

1- Using Apache Commons

if(StringUtils.isNotBlank(str) {
     list.add(str)
}

2- Optional & filter

Optional.ofNullable(str)
                .filter(s -> StringUtils.isNotBlank(s))
                .ifPresent(result -> list.add(result));

Answer 1

Question : Which approach is better and why

The first one , because in the second one you create an unnecessary Optional

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But I would suggest to use isNotEmpty instead of isNotBlank :

if(StringUtils.isNotEmpty(str)){
   list.add(str)
}

To know the difference between isNotEmpty and isNotBlank in doc:

Checks if a CharSequence is not empty ("") and not null .

Checks if a CharSequence is not empty (""), not null and not whitespace only .

In your case you ask null or empty, where isNotEmpty is the correct one for your case.

Answer 2

More of an addendum: my vote went almost immediately to your first option.

Why? Simply: simplicity!

The second snippet is nothing but an if-statement in disguise. And that disguise comes with plenty of overhead.

Your human readers have to look at all the characters, then they need to dissect the complex statement, then they need to know how Optional works, and what the given code actually does.

So, besides the subtle performance differences, as outlined in the other answer: the real answer: you should ask the people in your team.

If they are all used to Optional usage like here, and they do that all day long, then, maybe, the better style is option 2. Because that is what all of you do, day in day out. But if not, as said: I recommend to go with the simpler lines of code, that can be understood by anybody who knows basic java.