Stringutils. isempty and stringutils. isblank usage

1. The operation object of the stringutils method is Java. lang. string-type objects are complementary to the string-type operation method provided by JDK, and are null safe (that is, if the input parameter string is null, nullpointerexception is not thrown, but corresponding processing is performed, for example, if the input is null, the return value is also null. You can view the source code ).
3. In addition to the constringutils, there are more than 130 methods in stringutils and they are all static, so we can call stringutils. XXX () in this way ()
5. The following describes some common methods:
7. 1. Public static Boolean isempty (string Str)
8. Determines whether a string is null. If it is null, the standard is str = NULL or str. Length () = 0.
9. The following is an example of stringutils determining whether it is null:
11. Stringutils. isempty (null) = true
12. Stringutils. isempty ("") = true
13. Stringutils. isempty ("") = false // note that non-empty spaces are processed in stringutils.
14. Stringutils. isempty ("") = false
15. Stringutils. isempty ("Bob") = false
16. Stringutils. isempty ("Bob") = false
19. 2. Public static Boolean isnotempty (string Str)
20. Determines whether a string is not null. It is equal! Isempty (string Str)
21. The following is an example:
23. Stringutils. isnotempty (null) = false
24. Stringutils. isnotempty ("") = false
25. Stringutils. isnotempty ("") = true
26. Stringutils. isnotempty ("") = true
27. Stringutils. isnotempty ("Bob") = true
28. Stringutils. isnotempty ("Bob") = true
30. 3. Public static Boolean isblank (string Str)
31. Determines whether a string is null or has a length of 0 or is composed of whitespace.
32. The following is an example:
33. Stringutils. isblank (null) = true
34. Stringutils. isblank ("") = true
35. Stringutils. isblank ("") = true
36. Stringutils. isblank ("") = true
37. Stringutils. isblank ("\ t \ n \ f \ r") = true // For tabs, line breaks, page breaks, and carriage returns
39. Stringutils. isblank () // both are blank characters
40. Stringutils. isblank ("\ B") = false // "\ B" is the word boundary.
41. Stringutils. isblank ("Bob") = false
42. Stringutils. isblank ("Bob") = false
44. 4. Public static Boolean isnotblank (string Str)
45. Determines whether a string is not empty and its length is not 0. It cannot be composed of whitespace. It is equal! Isblank (string Str)
46. The following is an example:
48. Stringutils. isnotblank (null) = false
49. Stringutils. isnotblank ("") = false
50. Stringutils. isnotblank ("") = false
51. Stringutils. isnotblank ("") = false
52. Stringutils. isnotblank ("\ t \ n \ f \ r") = false
53. Stringutils. isnotblank ("\ B") = true
54. Stringutils. isnotblank ("Bob") = true
55. Stringutils. isnotblank ("Bob") = true
57. 5. Public static string trim (string Str)
58. Removes the control character (char <= 32) at both ends of the string. If the input is null, null is returned.
59. The following is an example:
60. Stringutils. Trim (null) = NULL
61. Stringutils. Trim ("") = ""
62. Stringutils. Trim ("") = ""
63. Stringutils. Trim ("\ B \ t \ n \ f \ r") = ""
64. Stringutils. Trim ("\ n \ TSS \ B") = "SS"
65. Stringutils. Trim ("d dd") = "d dd"
66. Stringutils. Trim ("DD") = "DD"
67. Stringutils. Trim ("DD") = "DD"
69. 6. Public static string trimtonull (string Str)
70. Removes the control character (char <= 32) at both ends of the string. If it is null or "", null is returned.
71. The following is an example:
72. Stringutils. trimtonull (null) = NULL
73. Stringutils. trimtonull ("") = NULL
74. Stringutils. trimtonull ("") = NULL
75. Stringutils. trimtonull ("\ B \ t \ n \ f \ r") = NULL
76. Stringutils. trimtonull ("\ n \ TSS \ B") = "SS"
77. Stringutils. trimtonull ("d dd") = "d dd"
78. Stringutils. trimtonull ("DD") = "DD"
79. Stringutils. trimtonull ("DD") = "DD"
81. 7. Public static string trimtoempty (string Str)
82. Removes the control character (char <= 32) at both ends of the string. If it is null or "", "" is returned ""
83. The following is an example:
84. Stringutils. trimtoempty (null) = ""
85. Stringutils. trimtoempty ("") = ""
86. Stringutils. trimtoempty ("") = ""
87. Stringutils. trimtoempty ("\ B \ t \ n \ f \ r") = ""
88. Stringutils. trimtoempty ("\ n \ TSS \ B") = "SS"
89. Stringutils. trimtoempty ("d dd") = "d dd"
90. Stringutils. trimtoempty ("DD") = "DD"
91. Stringutils. trimtoempty ("DD") = "DD"