Java - 使用正则表达式从 requestURI 中提取电子邮件地址

Question

我尝试使用下面的正则表达式从 requestURI 中提取电子邮件地址，这是基于 RFC-2822 的电子邮件正则表达式，它与验证配合良好

private final transient String EMAIL_REGEX = 
            "^([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]"
            + "+|\\x22([^\\x0d\\x22\\x5c\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x22)"
            + "(\\x2e([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+"
            + "|\\x22([^\\x0d\\x22\\x5c\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x22))"
            + "*\\x40([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+"
            + "|\\x5b([^\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x5d)"
            + "(\\x2e([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]"
            + "+|\\x5b([^\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x5d))*$";

我正在尝试重用相同的正则表达式来匹配并从 URI /something/users/myemail@email.com/somethingelse 中提取电子邮件地址，并使用 Matcher.group( 0) 我得到输出 /something/users/myemail@email.com ，因为我的预期输出只是 URI 中的电子邮件地址。

Answer 1

我提出了这个正则表达式更新:

private static String EMAIL_REGEX =
        "([^/\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]"
        + "+|\\x22([^\\x0d\\x22\\x5c\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x22)"
        + "(\\x2e([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+"
        + "|\\x22([^\\x0d\\x22\\x5c\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x22))"
        + "*\\x40([^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+"
        + "|\\x5b([^\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x5d)"
        + "(\\x2e([^/\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]"
        + "+|\\x5b([^\\x0d\\x5b-\\x5d\\x80-\\xff]|\\x5c[\\x00-\\x7f])*\\x5d))*";

请注意开头和倒数第二行的[^/\\x00。

请参阅online demo

String s = "/something/users/myemail@email.com/somethingelse";         
Matcher m = Pattern.compile(EMAIL_REGEX).matcher(s);
while (m.find())
{
    System.out.println(m.group());
} // => myemail@email.com