Java中的正则表达式不起作用

Question

I convert a excel file to a CSV , and that to a String.

The problem is that a regular expression is not working correctly

I want to detect this kind of text:

MYW Pkg, MYW Pkg + Quick Service Dining, MYW Pkg + Dining, MYW Pkg + Deluxe Dining,

Room + Tickets + Quick Service Dining

I have an array of String. So I need to know a pattern for that, I try this but it doesn't detect it:

Pattern.compile("([A-Z]{3})+(\\s)+([A-Za-z]{3})+(\\s)+(\\+)");

I try to match "MYW Pkg +" for example, Do you know why it is not working?

More code:

chain is the array with values like "MYW Pkg,"

Pattern patPackageDescription = Pattern.compile("([A-Z]{3})+(\\s)+([A-Za-z])+(\\s)+(\\+)");
        for (int i = 0; i < chain.length; i++) {
            Matcher matPackageDescription = patPackageDescription
                    .matcher(chain[i]);

            if (matPackageDescription.matches()) {
                String space = String.format("%1$-" + 50 + "s",
                        chain[i].toString());
                a.append(space + "|\n");
            }
        }

Regards.

Answer 1

matches() method tries to match the whole string against the pattern, to match a part of the string you need to use find() method.

String str = "MYW Pkg, MYW Pkg + Quick Service Dining, MYW Pkg + Dining, MYW Pkg + Deluxe Dining,";
Pattern patPackageDescription = Pattern.compile("([A-Za-z]{3}\\s)+\\+");
Matcher matPackageDescription = patPackageDescription.matcher(str);

while (matPackageDescription.find()) {
    System.out.println(matPackageDescription.group());
}

Outputs:

MYW Pkg +
MYW Pkg +
MYW Pkg +

Look here for an explanation.

Answer 2

Your problem is that you are using Matcher.matches() which requires a full match, if you can either use find() for partial matches or add .* to match anything after your search string.

([A-Z]{3})+(\s)+([A-Za-z]{3})+(\s)+(\+).*

Debuggex Demo