第一个位置没有空格的java正则表达式

Question

接受的例子：

This is a try!
And this is the second line!

不接受的示例：

      this is a try with initial spaces
and this the second line

所以，我需要：

• 没有仅由空格“”生成的字符串
• 没有第一个字符为空白的字符串
• 新台词还可以；只有第一个字符不能是新行

我在用

^(?=\s*\S).*$

但这种模式不允许出现新的线条

Answer 1

我不是Java爱好者，但Python中的解决方案可以如下所示：

In [1]: import re

In [2]: example_accepted = 'This is a try!\nAnd this is the second line!'

In [3]: example_not_accepted = '   This is a try with initial spaces\nand this the second line'

In [4]: pattern = re.compile(r"""
  ....:     ^     # matches at the beginning of a string
  ....:     \S    # matches any non-whitespace character
  ....:     .+    # matches one or more arbitrary characters
  ....:     $     # matches at the end of a string
  ....:     """,
  ....:     flags=re.MULTILINE|re.VERBOSE)

In [5]: pattern.findall(example_accepted)
Out[5]: ['This is a try!', 'And this is the second line!']

In [6]: pattern.findall(example_not_accepted)
Out[6]: ['and this the second line']

这里的关键部分是标志re.MULTILINE。启用此标志后，^和$不仅在字符串的开头和结尾匹配，而且在由换行符分隔的行的开头和结尾也匹配。我相信Java也有类似的东西