Java Inspection Bank card number

2. /*
4. Verification process:
6. 1. Starting with the last digit of the card number, the inverse adds the odd digits (1, 3, 5, and so on).
8. 2, starting from the last digit of the card number, the inverse of the even digit number, first multiplied by 2 (if the product is two digits, the bit 10 digits are added, will be minus 9), and then summed.
10. 3, the sum of odd digits plus even digits sum, the result should be divisible by 10.
12. */
14. /**  
16. * Verify the bank card number
18. */
20. public Static boolean checkbankcard (String bankcard) {
22. if (Bankcard.length () < | | bankcard.length () > ) {
24. return false;
26. }
28. char bit = Getbankcardcheckcode (bankcard.substring (0, Bankcard.length ()- 1));
30. if (bit = = ' N ') {
32. return false;
34. }
36. return Bankcard.charat (Bankcard.length ()- 1) = = bit;
38. }
42. /**  
44. * The check digit is obtained from the bank card number without check digit using LUHM check algorithm.
46. * @param noncheckcodebankcard
48. * @return
50. */
52. public static char getbankcardcheckcode (String noncheckcodebankcard) {
54. if (Noncheckcodebankcard = = Null | | Noncheckcodebankcard.trim (). Length () = = 0
56. || !noncheckcodebankcard.matches ("\\d+")) {
58. //If the data passed is not returned by N
60. return ' N ';
62. }
64. char[] CHS = Noncheckcodebankcard.trim (). ToCharArray ();
66. int luhmsum = 0;
68. for (int i = chs.length- 1, j = 0; I >= 0; I--, j + +) {
70. int k = chs[i]- ' 0 ';
72. if (j% 2 = = 0) {
74. K *= 2;
76. K = k/ ten + k% 10;
78. }
80. Luhmsum + = k;
82. }
84. return (luhmsum% = = 0)?    ' 0 ': (char) ((10-luhmsum% ) + ' 0 ');
86. }

Java Inspection Bank card number