Java正则表达式和转义元字符

问题描述

我正在尝试编写regexp来匹配嵌入在两个花括号之间的标记。例如，如果缓冲区 Hello {World} ，我想从String中获取World标记。当我使用regexp如 \ {* \} eclipse显示错误消息为

I am trying to write regexp for matching token embedded between two curly braces. For example if buffer Hello {World}, I want to get "World" token out of String. When I use regexp like \{*\} eclipse shows a error messages as

任何人都可以帮助我吗？我是新手使用正则表达式。

Can anyone please help me? I am new to using regular expressions.

推荐答案

您应该能够使用 {（\ w *）}的正则表达式从字符串中提取令牌，例如{token}。
括号（）形成一个捕获组，围绕由 \ w * 捕获的零个或多个单词字符。
如果字符串匹配，通过调用Matcher类上的group（）方法从捕获组中提取实际令牌。

You should be able to extract the token from a string such as "{token}" by using a regexp of {(\w*)}.The parentheses () form a capturing group around the zero or more word characters captured by \w*.If the string matches, extract the actual token from the capturing group by calling the group() method on the Matcher class.

Pattern p = Pattern.compile("\\{(\\w*)\\}");

Matcher m = p.matcher("{some_interesting_token}");

String token = null;
if (m.matches()) {
 token = m.group();
}

请注意，令牌可能是空字符串，因为正则表达式{\w *}将匹配{}。如果要匹配至少一个标记字符，请改用{\w +}。

Note that token may be an empty string because regex {\w*}" will match "{}". If you want to match on at least one token characters, use {\w+} instead.

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