Regular Expressions in Java

Regular Expressions in Java:

1: Common presentation rules:

1 \ \ backslash character (ie: \)2 3 4 character class5 [ABC] A, B or C (simple Class)6[^ABC] Any character except A, B, or C (negation)7[a-za-Z] A to Z or A to Z, the letters at both ends are included (range)8[A-d[m-p]] A to D or M to p:[a-dm-p] (and set)9[a-z&&[def]] D, E or F (intersection)Ten[A-Z&&[^BC]] A to Z, except for B and c:[ad-z] (minus) One[A-z&&[^m-p]] A to Z, not m to p:[a-lq-z] (minus) A  - Predefined character Classes - . Any character (may or may not match the line terminator)
\ transpose character (\ \ =: \,\\. means: \. ie: Point itself) the\d Number: [0-9]  -\d non-numeric: [^0-9]  - \s whitespace characters: [\t\n\x0b\f\r] -\s non-whitespace characters: [^\s] +\w Word character: [a-za-z_0-9]  -\w non-word characters: [^\w] +  A Boundary Matching Device at^the beginning of the line - end of the $ line - \b Word Boundaries - \b Non-word boundaries - \a The beginning of the input - \g The end of the previous match in \z the end of the input, only for the last terminator (if any) - \z end of input to  + greedy number of words -X?X, not once or once thex*X, 0 or more times *x+X, one or more times $ X{n} X, exactly n timesPanax Notoginseng X{n,} X, at least n times -X{n,m} X, at least n times, but no more than m times 

Example: 1: Determine whether the mobile phone number starts with 13 or 18 and satisfies 11 bits:

1  Public classRegexdemo {2      Public Static voidMain (string[] args) {3         //Keyboard Entry mobile phone number4Scanner sc =NewScanner (system.in);5System.out.println ("Please enter your mobile phone number:");6String phone =sc.nextline ();7         8         //rules for defining mobile numbers9String regex = "1[38]\\d{9}";Ten          One         //call function, Judge can A         BooleanFlag =phone.matches (regex); -          -         //Output Results theSystem.out.println ("flag:" +flag); -     } -}

2: Verify mailbox:

1 /*2 * Check Mailbox3  * 4 * Analysis:5 * A: Keyboard Entry Mailbox6 * B: Define the rules for the mailbox7 * [email protected]8 * [email protected]9 * [email protected]Ten * [email protected] One * [email protected] A * C: Call function, Judge can - * D: Output result -  */ the  Public classRegextest { -      Public Static voidMain (string[] args) { -         //Keyboard Entry Mailbox -Scanner sc =NewScanner (system.in); +System.out.println ("Please enter your email address:"); -String email =sc.nextline (); +          A         //define the rules for a mailbox at         //String regex = "[A-za-z_0-9][email protected][a-za-z_0-9]{2,6} (\\.[ a-za-z_0-9]{2,3}) + "; -String regex = "\\[email protected]\\w{2,6} (\\.\\w{2,3}) +"; -          -         //call function, Judge can -         BooleanFlag =email.matches (regex); -          in         //Output Results -System.out.println ("flag:" +flag); to     } +}

Regular Expressions in Java