java - 如何拆分仅包含定界符的字符串？

Question

我正在使用以下代码:

String sample = "::";
String[] splitTime = sample.split(":");
// extra detail omitted
System.out.println("Value 1 :"+splitTime[0]);
System.out.println("Value 2 :"+splitTime[1]);
System.out.println("Value 3 :"+splitTime[2]);

我遇到了 ArrayIndexOutofBound 异常。 String.split() 如何处理连续或尾随/开始的定界符？

另见:

• Doubt in split method
• Java split() method strips empty strings at the end?

Answer 1

Alnitak 是正确的，默认情况下尾随的空字符串将被丢弃。

如果你想要尾随空字符串，你应该使用split(String, int)并传递一个负数作为 limit 参数。

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. 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.

请注意 split(aString)是 split(aString, 0) 的同义词:

This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

此外，您应该使用循环从数组中获取值；这避免了可能的 ArrayIndexOutOfBoundsException。

因此，您更正后的代码应该是(假设您想要尾随的空字符串):

String sample = "::";
String[] splitTime = sample.split(":", -1);
for (int i = 0; i < splitTime.length; i++) {
    System.out.println("Value " + i + " : \"" + splitTime[i] + "\"");
}

输出:

Value 0 : ""Value 1 : ""Value 2 : ""