在Java中使用正则表达式查找纯文本中的值。

Question

I have a server that I am speaking with that speaks with plain text commands and responses. A sample response looks like

COMMENT: Monitor Version 2.2.1 
REQUIRE: IDENT
WAITING: 

I would like to use regular expressions to find information in the responses. At some points on line of the response might look like

RESPONSE: COMMANDSENT ARG1 ARG2 ... ARGN

I would like to use regex to find the string COMMANDSENT along with the resulting arguments up to ARGN . I am not sure how to do this.

I would have the expression read "If the string contains "RESPONSE" search for a ":" and return each token between spaces until a newline is encountered". Is this possible with regular expressions?

I have found quite a few guides but it is quite daunting to start, could someone give me some pointers on how to start on this, useful expressions that would help?

Answer 1

Perhaps you can do a String.split("RESPONSE") and then again split on spaces/colons on the resulting array?

Regex is a bit nasty in my experience.

Answer 2

尝试这个

String[] a = s.replaceAll("(?sm).*^RESPONSE: (.*?)$.*", "$1").split(" +");

Answer 3

I think split is the best way to go here. However, since you're new to regexes, here's an example of how it could be done with regexes. I'm making some assumptions about what your requirements are.

if (s.startsWith("RESPONSE:")) {
    String response = s.substring(9);  // this will take the part of the string after RESPONSE:
    Pattern pat = Pattern.compile(" *([^ ]+)");
        // the pattern is zero or more spaces, followed by one or more non-space
        // characters.  The non-space characters will be saved in a group, called
        // "group 1" since it's the first (and only) group.
    Matcher matcher = pat.matcher(response);
    ArrayList<String> args = new ArrayList<String>();
    while (matcher.find())
        args.add(matcher.group(1));
            // This repeatedly searches for the pattern, until it can't find it any
            // more.  Each time we find the pattern, we use group(1) to retrieve
            // "group 1", which is the non-space characters.  Each find() starts
            // where the previous match left off.

    // After this is done, args will contain the arguments.
}