不要逃避不需要转义的内容：

Don't escape what needs not to be escaped:

return expression.matches("[-+*/^]+");

应该可以正常工作。大多数正则表达式元字符（。，（，）， + ， * 等）在字符类中使用时会失去特殊含义。你需要注意的是 [， - ， ^ 和] 。而对于最后三个，你可以策略性地在其中放置char类，因此它们不具有其特殊含义：

should work just fine. Most regex metacharacters (., (, ), +, *, etc.) lose their special meaning when used in a character class. The ones you need to pay attention to are [, -, ^, and ]. And for the last three, you can strategically place in them char class so they don't take their special meaning:

• ^ 可以放在开头括号之后的任何地方： [a ^]


• - 可以放在开始括号之后或者在结束括号之前： [ - a] 或 [a - ]


• ] 可以放在左括号后面： [] a]

• ^ can be placed anywhere except right after the opening bracket: [a^]
• - can be placed right after the opening bracket or right before the closing bracket: [-a] or [a-]
• ] can be placed right after the opening bracket: []a]

但是为了将来参考，如果你需要包含一个反斜杠作为正则表达式字符串中的转义字符，您需要将其转义两次，例如：

But for future reference, if you need to include a backslash as an escape character in a regex string, you'll need to escape it twice, eg:

"\\(.*?\\)" // match something inside parentheses

所以要匹配文字反斜杠，你需要其中四个：

So to match a literal backslash, you'd need four of them:

"hello\\\\world" // this regex matches hello\world

另一个注意事项： String.matches（）会尝试将整个字符串与模式匹配，所以除非你的字符串只包含一堆运算符，你需要使用像 .matches（。* [ - + * / ^]。*）; 这样的东西（或使用 匹配器。 find（） ）

Another note: String.matches() will try to match the entire string against the pattern, so unless your string consists of just a bunch of operators, you'll need to use use something like .matches(".*[-+*/^].*"); instead (or use Matcher.find())