String.split（）是否有可能在结果数组中返回空节点？

Question

Is there any string out there that could return an array with a null node when .split is called? Here's what I tried:

    String string = "test,,test";
    if (string != null && !string.isEmpty()) {
        String[] parsedString = string.split(",");
        for (String stringNode : parsedString) {
            if (stringNode != null) {
                //perform logic here. Omitted for the purpose of this question.
            }
        }
    }

I want my method to be able handle a null string, but if String.split() can't return an array with a null node, then it is probably safe to remove right?

Answer 1

No, String.split(String regex) can never return an array with a null element in it.

There are only three cases to account for:

1. regex is invalid, a PatternSyntaxException is thrown
2. regex isn't found, the array will only contain the original string.
3. regex is found, the string is split.

Answer 2

Look at StringUtils

split( ) method.

String str = "1,2,3,,4";
    System.out.println(Arrays.toString(str.split(",")));
    System.out.println(Arrays.toString(StringUtils.split(str,",")));

output:

[1, 2, 3, , 4]
[1, 2, 3, 4]

Is this what you expect?

Hope this helps...

Answer 3

Yes, you can remove if (stringNode != null) . A null value will not be returned. An empty string might be returned by String.split() (as an array element, I mean).

Answer 4

根据Javadoc ，String.split（）不会返回null或空字符串。