Extract email from the specified string

Extract email from the specified string

 

1. Package net. util. Email;
3. Import java. util. RegEx. matcher;
4. Import java. util. RegEx. pattern;
6. Public class emailutil
7. {
8. /**
9. * Extract the specified string of email content from the specified string
10. */
11. Public static string parse (string content)
12. {
13. String email = NULL;
14. If (content = NULL | content. Length () <1 ){
15. Return email;
16. }
17. // Find @
18. Int beginpos;
19. Int I;
20. String token = "@";
21. String prehalf = "";
22. String sufhalf = "";
24. Beginpos = content. indexof (token );
25. If (beginpos>-1 ){
26. // Previous scan
27. String S = NULL;
28. I = beginpos;
29. While (I> 0 ){
30. S = content. substring (I-1, I );
31. If (isletter (s ))
32. Prehalf = S + prehalf;
33. Else
34. Break;
35. I --;
36. }
37. // Post-item Scan
38. I = beginpos + 1;
39. While (I <content. Length ()){
40. S = content. substring (I, I + 1 );
41. If (isletter (s ))
42. Sufhalf = sufhalf + S;
43. Else
44. Break;
45. I ++;
46. }
47. // Determine validity
48. Email = prehalf + "@" + sufhalf;
49. If (isemail (email )){
50. Return email;
51. }
52. }
53. Return NULL;
54. }
56. /**
57. * Check whether the email address is valid.
58. */
59. Private Static Boolean isemail (string email ){
60. Try {
61. If (email = NULL | email. Length () <1 | email. Length ()> 256 ){
62. Return false;
63. }
65. String check = "^ ([0-9a-za-z] + [_. 0-9a-za-z-] +) @ ([a-zA-Z0-9-] + [.]) + ([A-Za-Z] {2, 3}) $ ";
66. Pattern RegEx = pattern. Compile (check );
67. Matcher = RegEx. matcher (email );
68. Boolean ismatched = matcher. Matches ();
69. If (ismatched ){
70. Return true;
71. } Else {
72. Return false;
73. }
74. } Catch (runtimeexception e ){
75. Return false;
76. }
77. }
79. /**
80. * Determine whether the character is valid. C: the character to be judged.
81. */
82. Private Static Boolean isletter (string C)
83. {
84. Boolean result = false;
86. If (C = NULL | C. Length () <0 ){
87. Return false;
88. }
89. // A-z
90. If (C. comparetoignorecase ("A")> = 0 & C. comparetoignorecase ("Z") <= 0 ){
91. Return true;
92. }
93. // 0-9
94. If (C. comparetoignorecase ("0")> = 0 & C. comparetoignorecase ("9") <= 0 ){
95. Return true;
96. }
97. //.-_
98. If (C. Equals (".") | C. Equals ("-") | C. Equals ("_")){
99. Return true;
100. }
101. Return result;
102. }
103. }