java - 在 Java 中拆分一个空字符串似乎违反了文档，因为它不丢弃尾随的空字符串

Question

System.out.println(",".split(",", 0).length);
System.out.println("".split(",", 0).length);

打印:

0
1

这看起来很奇怪。根据 String.split(pattern, n) 的文档,

If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

在第二种情况下，当拆分一个空字符串时，这条规则似乎被忽略了。这是预期的行为吗？

Answer 1

来自文档

If the expression does not match any part of the input then the resulting array has just one element, namely this string

"".split(",", 0).length 表示类似这样

    System.out.println(new String[]{""}.length);

字符串 "" 中没有 , 因此数组包含单个元素 "" 一个空字符串，导致数组长度为1

另一个例子

    System.out.println("aaa".split(",", 0).length); // 1
    System.out.println("aaa".split("," , 0)[0]);    // aaa