Stringutil packet Function Learning __ function

Stringutil Package FunctionStringutil Package function
First, the array is converted into a string:
1, stringutil.convstring (string[] str) converts the characters in the array to a string
STRING[3] s = {"A", "B", "C"}
Stringutil.convstring (s) = "A,b,c"
2. Static public string converstring (string[] str, string splitstr) converts characters in an array to a string to specify character segmentation
STRING[3] s = {"A", "B", "C"};
Stringutil.convstring (S, "@") = "a@b@c";


Two, the null value detection:
3. Stringutils.isempty (string str) determines whether a string is empty and the space is not null-treated. Stringutils.isempty (NULL) = True Stringutils.isempty ("") = True Stringutils.isempty ("") = False Stringutils.isempty (" Bob ") = False Stringutils.isempty (" Bob ") = False
4. public static Boolean IsBlank (String str) determines whether a string is empty and the space is null-treated. Stringutils.isnotblank (NULL) = True Stringutils.isblank ("") = True Stringutils.isblank ("") = True Stringutils.isblank (" Bob ") = False Stringutils.isblank (" Bob ") = False
Iii. non-null processing:
5, Stringutils.isnotempty (String str) to determine whether a string is not empty, the space is not NULL processing. Stringutils.isnotempty (NULL) = False Stringutils.isnotempty ("") = False Stringutils.isnotempty ("") = True stringutils. Isnotempty ("Bob") = True Stringutils.isnotempty ("Bob") = True

6. public static Boolean Isnotblank (String str) determines whether a string is not empty and the space is null-treated. Stringutils.isnotblank (NULL) = False Stringutils.isnotblank ("") = False Stringutils.isnotblank ("") = False stringutils . Isnotblank ("Bob") = True Stringutils.isnotblank ("Bob") = True

Four, space processing
7. public static string trim (string str) formats a space in a string, has a non-null judgment processing stringutils.trim (NULL) = null Stringutils.trim ("") = "" Stringutils.trim ("") = "" Stringutils.trim ("abc") = "abc" Stringutils.trim ("abc") = "abc"

8. public static string Trimtonull (String str)
Formats a space in a string that has non-null judgment processing if NULL stringutils.trimtonull (NULL) = null stringutils.trimtonull ("") = null Stringutils.trimtonull ("") = null stringutils.trimtonull ("abc") = "abc" Stringutils.trimtonull ("abc") = "abc"

9. public static string Trimtoempty (String str) formats a space in a string, has non-null judgment processing, and if NULL returns "" Stringutils.trimtoempty (NULL) = "" String Utils.trimtoempty ("") = "" Stringutils.trimtoempty ("") = "" Stringutils.trimtoempty ("abc") = "abc" Stringutils.trimtoe Mpty ("abc") = "abc"

Five, string comparison:
10, public static Boolean equals (String str1, String str2)
Determines whether two strings are equal, has non-null processing stringutils.equals (null, NULL) = True stringutils.equals (NULL, "abc") = False Stringutils.equals ("ABC ", NULL) = False Stringutils.equals (" ABC "," abc ") = True Stringutils.equals (" abc "," abc ") = False

11. public static Boolean Equalsignorecase (String str1, String str2)
Determines whether two strings are equal and has non-null processing. Ignore case stringutils.equalsignorecase (null, NULL) = True Stringutils.equalsignorecase (NULL, "abc") = False stringutils.equ Alsignorecase ("abc", NULL) = False Stringutils.equalsignorecase ("ABC", "abc") = True Stringutils.equalsignorecase ("ABC "," ABC ") = True

Vi. Treatment of IndexOf
12. public static int indexOf (String str, string searchstr)
Returns the location of the string to find, with non-null processing stringutils.indexof (NULL, *) =-1 stringutils.indexof (*, NULL) =-1 Stringutils.indexof ("", "") = 0 Stringutils.indexof ("Aabaabaa", "a") = 0 stringutils.indexof ("Aabaabaa", "B") = 2 Stringutils.indexof ("Aabaabaa", "AB" = 1 Stringutils.indexof ("Aabaabaa", "") = 0

13. public static int indexOf (String str, string searchstr, int startpos)
Returns the location of the string to be looked at at the specified location, with non-null processing stringutils.indexof (NULL, *, *) =-1 stringutils.indexof (*, NULL, *) =-1 Stringutils.indexo F ("", "", 0) = 0 stringutils.indexof ("Aabaabaa", "a", 0) = 0 stringutils.indexof ("Aabaabaa", "B", 0) = 2 stringutils.in  Dexof ("Aabaabaa", "AB", 0) = 1 stringutils.indexof ("Aabaabaa", "B", 3) = 5 Stringutils.indexof ("Aabaabaa", "B", 9) =-1 Stringutils.indexof ("Aabaabaa", "B",-1) = 2 Stringutils.indexof ("Aabaabaa", "", 2) = 2 Stringutils.indexof ("abc", "", 9) = 3

Seven, substring processing:
14. public static string substring (string str, int start)
Returns all characters in the string starting at the specified position stringutils.substring (NULL, *) = null stringutils.substring ("", *) = "" Stringutils.substring ("abc", 0) = "abc" stringutils.substring ("abc", 2) = "C" stringutils.substring ("abc", 4) = "" Stringutils.substring ("abc",-2) = "BC" stringutils.substring ("abc",-4) = "ABC"

15. public static string substring (string str, int start, int end)
Returns the substring between the start position and the end position stringutils.substring (NULL, *, *) = null stringutils.substring ("", *, *) = "" Stringutils.substring ("abc", 0, 2) = "AB" stringutils.substring ("abc", 2, 0) = "" Stringutils.substring ("abc", 2, 4) = "C" Stringutils.subst Ring ("ABC", 4, 6) = "" Stringutils.substring ("abc", 2, 2) = "" Stringutils.substring ("abc",-2,-1) = "B" stringutils.s Ubstring ("abc", -4, 2) = "AB"

16, Substringafter/substringbefore before and after the substring processing: Returns all characters before the specified string Stringutils.substringbefore (null, *) = NULL Stringutils.substringbefore ("", *) = "" Stringutils.substringbefore ("abc", "a") = "" Stringutils.substringbefore (" ABCBA "," B ") =" a "Stringutils.substringbefore (" abc "," C ") =" AB "Stringutils.substringbefore (" abc "," D ") =" abc "Strin Gutils.substringbefore ("abc", "") = "" Stringutils.substringbefore ("abc", NULL) = "ABC"

17. public static string Substringafter (String str, string separator)
Returns all characters after the specified string Stringutils.substringafter (null, *) = null stringutils.substringafter ("", *) = "" Stringutils.substringa fter (*, NULL) = "" Stringutils.substringafter ("abc", "a") = "BC" Stringutils.substringafter ("ABCBA", "B") = "CBA" Strin Gutils.substringafter ("abc", "C") = "" Stringutils.substringafter ("abc", "D") = "" Stringutils.substringafter ("abc", "" " ) = "ABC"

18. public static string Substringbeforelast (String str, string separator)
Returns all characters before the last specified string stringutils.substringbeforelast (null, *) = null stringutils.substringbeforelast ("", *) = "" Stringut  Ils.substringbeforelast ("ABCBA", "B") = "abc" Stringutils.substringbeforelast ("abc", "C") = "AB"  Stringutils.substringbeforelast ("A", "a") = "" Stringutils.substringbeforelast ("a", "z") = "a" Stringutils.substringbeforelast ("A", null) = "a" Stringutils.substringbeforelast ("a", "") = "a"

19. public static string Substringafterlast (String str, string separator)
Returns all characters after the last specified string stringutils.substringafterlast (null, *) = null stringutils.substringafterlast ("", *) = "" Stringutil S.substringafterlast (*, "") = "" Stringutils.substringafterlast (*, NULL) = "" Stringutils.substringafterlast ("abc", "A" = "BC" Stringutils.substringafterlast ("ABCBA", "B") = "a" Stringutils.substringafterlast ("abc", "C") = "" StringUtils . Substringafterlast ("A", "a") = "" Stringutils.substringafterlast ("a", "z") = ""

Eight, replacing (string replacement)
20. public static string replace (string text, String Repl, string with)
Replaces the specified string of the original string with the specified string Stringutils.replace (NULL, *, *) = null stringutils.replace ("", *, *) = "" Stringutils.replace ("ABA ", NULL, NULL) =" ABA "Stringutils.replace (" ABA ", NULL, NULL) =" ABA "Stringutils.replace (" ABA "," a ", null) =" ABA "Str Ingutils.replace ("ABA", "a", "") = "ABA" Stringutils.replace ("ABA", "a", "z") = "ZBZ"
21. public static string replace (string text, String Repl, string with, int max)
Replaces the specified string of the original string with the specified string Stringutils.replace (NULL, *, *, *) = null stringutils.replace ("", *, *, *) = "" Stringutils.repl Ace ("Abaa", NULL, NULL, 1) = "Abaa" Stringutils.replace ("Abaa", NULL, NULL, 1) = "Abaa" Stringutils.replace ("Abaa", "a", NULL, 1) = "Abaa" Stringutils.replace ("Abaa", "a", "", 1) = "Abaa"