正则表达式不起作用（Java）

Question

I want to make a regular expression that matches the form (+92)-(21)-1234... . I made this program

public static void main(String[] args) {

    // A regex and a string in which to search are specifi ed
    String regEx = "([+]\\d{2})-(\\d{2})-\\d+";
    String phoneNumber = "(+92)-(21)-1234567890";

    // Obtain the required matcher
    Pattern pattern = Pattern.compile(regEx);
    Matcher matcher = pattern.matcher(phoneNumber);

    if (matcher.matches()) {
        System.out.println("Phone Number Valid");
    } else {
        System.out.println("Phone Number must be in the form (+xx)-(xx)-xxxxx..");
    }

} //end of main()

The regular expression i created like starts with the bracket( ( ), + [+] , two numbers( \\d{2} ), bracket close( ) ), a dash( - ), start bracket( ( ), two numbers( \\d{2} ), bracket close( ) ), a dash( - ) and then any number of digits( \\d+ ). But it is not working. What i am doing wrong?

Thanks

Answer 1

The regular expression i created like starts with the bracket(()

No, it starts with a grouping construct - that's what an unescaped ( means in a regular expression. I haven't looked at the rest of the expression in detail, but try just escaping the brackets:

String regEx = "\\([+]\\d{2}\\)-\\(\\d{2}\\)-\\d+";

Or a nicer (IMO) way of saying that you need the +

String regEx = "\\(\\+\\d{2}\\)-\\(\\d{2}\\)-\\d+";

Answer 2

转义括号和破折号

Answer 3

You need to escape the parantheses (as Jon already mentioned they create a capturing group):

public static void main(String[] args) {

     // A regex and a string in which to search are specifi ed
     String regEx = "\\([+]\\d{2}\\)-\\(\\d{2}\\)-\\d+";
     String phoneNumber = "(+92)-(21)-1234567890";

     // Obtain the required matcher
     Pattern pattern = Pattern.compile(regEx);
     Matcher matcher = pattern.matcher(phoneNumber);

     if (matcher.matches()) {
         System.out.println("Phone Number Valid");
     } else {
         System.out.println("Phone Number must be in the form (+xx)-(xx)-xxxxx..");
     }

}

Output:

Phone Number Valid

Answer 4

The correct regex is

[(][+]\\d{2}[)]-[(]\\d{2}[)]-\\d+

You just needed to put your brackets between [ and ].

Answer 5

if the plus symbol is always there you could just write \\\\+ , if it may or may not be there, \\\\+? . You should escape all regex-specific characters like this

String regEx = "\\(\\+\\d{2}\\)-\\(\\d{2}\\)-\\d+";