java - ^ 正则表达式分割什么样的字符串

Question

如果我有类似的 split 语句

String array1[]= test.split("^");

可能的测试字符串值是什么，这样这个(“^”)正则表达式将分割测试字符串？

我知道 ^ 是 Java 正则表达式中的特殊字符 - 它意味着“匹配输入的开头”。

Answer 1

what could be the possible test string value such that this ("^") regex will split the test string?

^ 匹配 Java 中行的开头。

根据模式documentation :

By default, the regular expressions ^ and $ ignore line terminators and only match at the beginning and the end, respectively, of the entire input sequence. If MULTILINE mode is activated then ^ matches at the beginning of input and after any line terminator except at the end of input. When in MULTILINE mode $ matches just before a line terminator or the end of the input sequence. (Emphasis, mine)

因此，以下代码将产生以下输出:

Pattern pattern = Pattern.compile("^", Pattern.MULTILINE);
System.out.println(Arrays.toString(pattern.split("Test\nTest")));

输出:

[Test
, Test]

如您所见，String已成功拆分。