因为您要处理嵌套的括号/括号，所以处理它们的“正确”方法是分别标记它们，并跟踪您的嵌套级别。因此，对于不同的令牌类型，您确实需要多个正则表达式，而不是单个正则表达式。
这是 Python，但转换为 Java 应该不会太难。
# just comma
sep_re = re.compile(r',')
# open paren or open bracket
inc_re = re.compile(r'[[(]')
# close paren or close bracket
dec_re = re.compile(r'[)\]]')
# string literal
# (I was lazy with the escaping. Add other escape sequences, or find an
# "official" regex to use.)
chunk_re = re.compile(r'''"(?:[^"\\]|\\")*"|'(?:[^'\\]|\\')*[']''')
# This class could've been just a generator function, but I couldn;'t
# find a way to manage the state in the match function that wasn't
# awkward.
class tokenizer:
def __init__(self):
self.pos = 0
def _match(self, regex, s):
m = regex.match(s, self.pos)
if m:
self.pos += len(m.group(0))
self.token = m.group(0)
else:
self.token = ''
return self.token
def tokenize(self, s):
field = '' # the field we're working on
depth = 0 # how many parens/brackets deep we are
while self.pos < len(s):
if not depth and self._match(sep_re, s):
# In Java, change the "yields" to append to a List, and you'll
# have something roughly equivalent (but non-lazy).
yield field
field = ''
else:
if self._match(inc_re, s):
depth += 1
elif self._match(dec_re, s):
depth -= 1
elif self._match(chunk_re, s):
pass
else:
# everything else we just consume one character at a time
self.token = s[self.pos]
self.pos += 1
field += self.token
yield field
用法：
>>> list(tokenizer().tokenize('foo=(3,(5+7),8),bar="hello,world",baz'))
['foo=(3,(5+7),8)', 'bar="hello,world"', 'baz']
这个实现有一些捷径：
- 字符串转义真的很懒惰：它只支持
\"双引号字符串和\'单引号字符串。这很容易解决。
- 它只跟踪嵌套级别。它不验证括号是否与括号匹配（而不是括号）。如果您关心这一点，您可以更改
depth为某种堆栈并将其推入/弹出括号/括号。