commons-lang3：StringUtils

字符串工具類

abbreviate(String str, int maxWidth) 返回一個指定長度加省略號的字符串，maxWidth必須大於3

StringUtils.abbreviate(null, *)      = null
StringUtils.abbreviate("", 4)        = ""
StringUtils.abbreviate("abcdefg", 6) = "abc..."
StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
StringUtils.abbreviate("abcdefg", 4) = "a..."
StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException

abbreviate(String str, int offset, int maxWidth) 返回一個指定長度加省略號的字符串，maxWidth必須大於3

abbreviate(String str, String abbrevMarker, int maxWidth) 返回一個自定義省略號的指定長度字符串，maxWidth必須大於3

StringUtils.abbreviate(null, "...", *)      = null
StringUtils.abbreviate("abcdefg", null, *)  = "abcdefg"
StringUtils.abbreviate("", "...", 4)        = ""
StringUtils.abbreviate("abcdefg", ".", 5)   = "abcd."
StringUtils.abbreviate("abcdefg", ".", 7)   = "abcdefg"
StringUtils.abbreviate("abcdefg", ".", 8)   = "abcdefg"
StringUtils.abbreviate("abcdefg", "..", 4)  = "ab.."
StringUtils.abbreviate("abcdefg", "..", 3)  = "a.."
StringUtils.abbreviate("abcdefg", "..", 2)  = IllegalArgumentException
StringUtils.abbreviate("abcdefg", "...", 3) = IllegalArgumentException

abbreviateMiddle(String str, String abbrevMarker, int maxWidth) 將字符串縮短到指定長度（length），字符串的中間部分用替換字符串（middle）顯示

StringUtils.abbreviateMiddle("abc", null, 0)      = "abc"
StringUtils.abbreviateMiddle("abc", ".", 0)      = "abc"
StringUtils.abbreviateMiddle("abc", ".", 3)      = "abc"
StringUtils.abbreviateMiddle("abcdef", ".", 4)     = "ab.f"

appendIfMissing(String str, CharSequence suffix, CharSequence... suffixes) 若是str不是以任何suffixes結尾，將字符串suffix拼接到字符串str後面

StringUtils.appendIfMissing(null, null) = null
StringUtils.appendIfMissing("abc", null) = "abc"
StringUtils.appendIfMissing("", "xyz") = "xyz"
StringUtils.appendIfMissing("abc", "xyz") = "abcxyz"
StringUtils.appendIfMissing("abcxyz", "xyz") = "abcxyz"
StringUtils.appendIfMissing("abcXYZ", "xyz") = "abcXYZxyz"

appendIfMissingIgnoreCase(String str, CharSequence suffix, CharSequence... suffixes) 同上 不區分大小寫

capitalize(String str) 將字符串第一個字符大寫並返回

center(String str, int size) 用空格字符填充使字符串str位於長度爲size的大字符串中間

StringUtils.center(null, *)   = null
StringUtils.center("", 4)     = "    "
StringUtils.center("ab", -1)  = "ab"
StringUtils.center("ab", 4)   = " ab "
StringUtils.center("abcd", 2) = "abcd"
StringUtils.center("a", 4)    = " a  "

center(String str, int size, char padChar) 用指定字符填充使字符串str位於長度爲size的大字符串中間

chomp(String str) 刪除字符串末尾的一個換行符,返回一個新的字符串（換行符"n", "r", or "rn"）

StringUtils.chomp(null)          = null
StringUtils.chomp("")            = ""
StringUtils.chomp("abc \r")      = "abc "
StringUtils.chomp("abc\n")       = "abc"
StringUtils.chomp("abc\r\n")     = "abc"
StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
StringUtils.chomp("abc\n\r")     = "abc\n"
StringUtils.chomp("abc\n\rabc")  = "abc\n\rabc"
StringUtils.chomp("\r")          = ""
StringUtils.chomp("\n")          = ""
StringUtils.chomp("\r\n")        = ""

chop(String str) 刪除字符串末尾的一個字符，返回一個新的字符串

StringUtils.chop(null)          = null
StringUtils.chop("")            = ""
StringUtils.chop("abc \r")      = "abc "
StringUtils.chop("abc\n")       = "abc"
StringUtils.chop("abc\r\n")     = "abc"
StringUtils.chop("abc")         = "ab"
StringUtils.chop("abc\nabc")    = "abc\nab"
StringUtils.chop("a")           = ""
StringUtils.chop("\r")          = ""
StringUtils.chop("\n")          = ""
StringUtils.chop("\r\n")        = ""

compare(String str1, String str2) 比較兩個字符串，返回一個int值

str1等於str2（或都爲空）返回0
str1小於str2返回小於0
str1大於str2返回大於0

StringUtils.compare(null, null)   = 0
StringUtils.compare(null , "a")   < 0
StringUtils.compare("a", null)    > 0
StringUtils.compare("abc", "abc") = 0
StringUtils.compare("a", "b")     < 0
StringUtils.compare("b", "a")     > 0
StringUtils.compare("a", "B")     > 0
StringUtils.compare("ab", "abc")  < 0

contains(CharSequence seq, CharSequence searchSeq) 檢查字符串中是否包含指定字符，返回boolean

StringUtils.contains(null, *)     = false
StringUtils.contains(*, null)     = false
StringUtils.contains("", "")      = true
StringUtils.contains("abc", "")   = true
StringUtils.contains("abc", "a")  = true
StringUtils.contains("abc", "z")  = false

containsAny(CharSequence cs, CharSequence... searchCharSequences) 檢查字符串中是否包含任一字符，返回boolean

StringUtils.containsAny(null, *)            = false
StringUtils.containsAny("", *)              = false
StringUtils.containsAny(*, null)            = false
StringUtils.containsAny(*, [])              = false
StringUtils.containsAny("abcd", "ab", null) = true
StringUtils.containsAny("abcd", "ab", "cd") = true
StringUtils.containsAny("abc", "d", "abc")  = true

containsNone(CharSequence cs, String invalidChars) 檢查字符串不包含指定字符，返回boolean

StringUtils.containsNone(null, *)       = true
StringUtils.containsNone(*, null)       = true
StringUtils.containsNone("", *)         = true
StringUtils.containsNone("ab", "")      = true
StringUtils.containsNone("abab", "xyz") = true
StringUtils.containsNone("ab1", "xyz")  = true
StringUtils.containsNone("abz", "xyz")  = false

containsOnly(CharSequence cs, String validChars) 檢查字符串只包含特定的字符，返回boolean

StringUtils.containsOnly(null, *)       = false
StringUtils.containsOnly(*, null)       = false
StringUtils.containsOnly("", *)         = true
StringUtils.containsOnly("ab", "")      = false
StringUtils.containsOnly("abab", "abc") = true
StringUtils.containsOnly("ab1", "abc")  = false
StringUtils.containsOnly("abz", "abc")  = false

containsWhitespace(CharSequence seq) 檢查字符串中是否包含空格字符，返回boolean

countMatches(CharSequence str, CharSequence sub) 檢查字符串中出現指定字符的次數，返回一個int值

StringUtils.countMatches(null, *)       = 0
StringUtils.countMatches("", *)         = 0
StringUtils.countMatches("abba", null)  = 0
StringUtils.countMatches("abba", "")    = 0
StringUtils.countMatches("abba", "a")   = 2
StringUtils.countMatches("abba", "ab")  = 1
StringUtils.countMatches("abba", "xxx") = 0

defaultIfBlank(T str, T defaultStr) 若是字符串爲null、空（""），或全是空格，將返回指定字符串，不然返回原值

StringUtils.defaultIfBlank(null, "NULL")  = "NULL"
StringUtils.defaultIfBlank("", "NULL")    = "NULL"
StringUtils.defaultIfBlank(" ", "NULL")   = "NULL"
StringUtils.defaultIfBlank("bat", "NULL") = "bat"
StringUtils.defaultIfBlank("", null)      = null

defaultIfEmpty(T str, T defaultStr) 若是字符串爲null、空（""），將返回指定字符串，不然返回原值

StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
StringUtils.defaultIfEmpty(" ", "NULL")   = " "
StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
StringUtils.defaultIfEmpty("", null)      = null

defaultString(String str) 若是字符串爲null，將返回空的字符串（""），不然返回原值

StringUtils.defaultString(null)  = ""
StringUtils.defaultString("")    = ""
StringUtils.defaultString("bat") = "bat"

defaultString(String str, String defaultStr) 若是字符串爲null，將返回指定字符，不然返回原值

StringUtils.defaultString(null, "NULL")  = "NULL"
StringUtils.defaultString("", "NULL")    = ""
StringUtils.defaultString("bat", "NULL") = "bat"

deleteWhitespace(String str) 刪除字符串中的空格字符，並返回新的字符串

StringUtils.deleteWhitespace(null)         = null
StringUtils.deleteWhitespace("")           = ""
StringUtils.deleteWhitespace("abc")        = "abc"
StringUtils.deleteWhitespace("   ab  c  ") = "abc"

difference(String str1, String str2) 比較兩個字符串差別，並返回差別的字符，返回第二個字符串的剩餘部分，這意味着「ABC」和「AB」之間的區別是空字符串而不是「C」。

StringUtils.difference(null, null) = null
StringUtils.difference("", "") = ""
StringUtils.difference("", "abc") = "abc"
StringUtils.difference("abc", "") = ""
StringUtils.difference("abc", "abc") = ""
StringUtils.difference("abc", "ab") = ""
StringUtils.difference("ab", "abxyz") = "xyz"
StringUtils.difference("abcde", "abxyz") = "xyz"
StringUtils.difference("abcde", "xyz") = "xyz"

endsWith(CharSequence str, CharSequence suffix) 檢查字符串是否以指定字符結尾，返回一個boolean

StringUtils.endsWith(null, null)      = true
StringUtils.endsWith(null, "def")     = false
StringUtils.endsWith("abcdef", null)  = false
StringUtils.endsWith("abcdef", "def") = true
StringUtils.endsWith("ABCDEF", "def") = false
StringUtils.endsWith("ABCDEF", "cde") = false
StringUtils.endsWith("ABCDEF", "")    = true

endsWithAny(CharSequence sequence, CharSequence... searchStrings) 檢查字符串是否以指定字符數組結尾，返回一個boolean

StringUtils.endsWithAny(null, null)      = false
StringUtils.endsWithAny(null, new String[] {"abc"})  = false
StringUtils.endsWithAny("abcxyz", null)     = false
StringUtils.endsWithAny("abcxyz", new String[] {""}) = true
StringUtils.endsWithAny("abcxyz", new String[] {"xyz"}) = true
StringUtils.endsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
StringUtils.endsWithAny("abcXYZ", "def", "XYZ") = true
StringUtils.endsWithAny("abcXYZ", "def", "xyz") = false

endsWithIgnoreCase(CharSequence str, CharSequence suffix) 檢查字符串是否以指定字符（不區分大小寫）結尾，返回一個boolean

StringUtils.endsWithIgnoreCase(null, null)      = true
StringUtils.endsWithIgnoreCase(null, "def")     = false
StringUtils.endsWithIgnoreCase("abcdef", null)  = false
StringUtils.endsWithIgnoreCase("abcdef", "def") = true
StringUtils.endsWithIgnoreCase("ABCDEF", "def") = true
StringUtils.endsWithIgnoreCase("ABCDEF", "cde") = false

equals(CharSequence cs1, CharSequence cs2) 比較兩個字符串是否相等，返回一個boolean

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

equalsAnyIgnoreCase(CharSequence string, CharSequence... searchStrings) 比較兩個字符串是否相等（不區分大小寫），返回一個boolean

StringUtils.equalsIgnoreCase(null, null)   = true
StringUtils.equalsIgnoreCase(null, "abc")  = false
StringUtils.equalsIgnoreCase("abc", null)  = false
StringUtils.equalsIgnoreCase("abc", "abc") = true
StringUtils.equalsIgnoreCase("abc", "ABC") = true

equalsAny(CharSequence string, CharSequence... searchStrings) 比較字符串是否與指定字符串數組中某一值相等，返回一個boolean

StringUtils.equalsAny(null, (CharSequence[]) null) = false
StringUtils.equalsAny(null, null, null)    = true
StringUtils.equalsAny(null, "abc", "def")  = false
StringUtils.equalsAny("abc", null, "def")  = false
StringUtils.equalsAny("abc", "abc", "def") = true
StringUtils.equalsAny("abc", "ABC", "DEF") = false

equalsAnyIgnoreCase(CharSequence string, CharSequence... searchStrings) 比較字符串是否與指定字符串數組中某一值相等（不區分大小寫），返回一個boolean

StringUtils.equalsAnyIgnoreCase(null, (CharSequence[]) null) = false
StringUtils.equalsAnyIgnoreCase(null, null, null)    = true
StringUtils.equalsAnyIgnoreCase(null, "abc", "def")  = false
StringUtils.equalsAnyIgnoreCase("abc", null, "def")  = false
StringUtils.equalsAnyIgnoreCase("abc", "abc", "def") = true
StringUtils.equalsAnyIgnoreCase("abc", "ABC", "DEF") = true

getCommonPrefix(String... strs) 獲取字符串數組元素公共字符，返回string

StringUtils.getCommonPrefix(null) = ""
StringUtils.getCommonPrefix(new String[] {}) = ""
StringUtils.getCommonPrefix(new String[] {"abc"}) = "abc"
StringUtils.getCommonPrefix(new String[] {null, null}) = ""
StringUtils.getCommonPrefix(new String[] {"", ""}) = ""
StringUtils.getCommonPrefix(new String[] {"", null}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", null, null}) = ""
StringUtils.getCommonPrefix(new String[] {null, null, "abc"}) = ""
StringUtils.getCommonPrefix(new String[] {"", "abc"}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", ""}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", "abc"}) = "abc"
StringUtils.getCommonPrefix(new String[] {"abc", "a"}) = "a"
StringUtils.getCommonPrefix(new String[] {"ab", "abxyz"}) = "ab"
StringUtils.getCommonPrefix(new String[] {"abcde", "abxyz"}) = "ab"
StringUtils.getCommonPrefix(new String[] {"abcde", "xyz"}) = ""
StringUtils.getCommonPrefix(new String[] {"xyz", "abcde"}) = ""
StringUtils.getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) = "i am a "

indexOf(CharSequence seq, CharSequence searchSeq) 檢查指定字符在字符串中出現的位置，返回一個int值

StringUtils.indexOf(null, *)          = -1
StringUtils.indexOf(*, null)          = -1
StringUtils.indexOf("", "")           = 0
StringUtils.indexOf("", *)            = -1 (except when * = "")
StringUtils.indexOf("aabaabaa", "a")  = 0
StringUtils.indexOf("aabaabaa", "b")  = 2
StringUtils.indexOf("aabaabaa", "ab") = 1
StringUtils.indexOf("aabaabaa", "")   = 0

indexOfIgnoreCase(CharSequence seq, CharSequence searchSeq) 檢查指定字符在字符串中出現的位置（不區分大小寫），返回一個int值

isAllBlank(CharSequence... css) 檢查數組全部字符是否爲null、empty、或全是空格字符，返回一個boolean

StringUtils.isAllBlank(null)             = true
StringUtils.isAllBlank(null, "foo")      = false
StringUtils.isAllBlank(null, null)       = true
StringUtils.isAllBlank("", "bar")        = false
StringUtils.isAllBlank("bob", "")        = false
StringUtils.isAllBlank("  bob  ", null)  = false
StringUtils.isAllBlank(" ", "bar")       = false
StringUtils.isAllBlank("foo", "bar")     = false
StringUtils.isAllBlank(new String[] {})  = true

isAllEmpty(CharSequence... css) 檢查數組全部字符是否爲null、empty，返回一個boolean

StringUtils.isAllEmpty(null)             = true
StringUtils.isAllEmpty(null, "")         = true
StringUtils.isAllEmpty(new String[] {})  = true
StringUtils.isAllEmpty(null, "foo")      = false
StringUtils.isAllEmpty("", "bar")        = false
StringUtils.isAllEmpty("bob", "")        = false
StringUtils.isAllEmpty("  bob  ", null)  = false
StringUtils.isAllEmpty(" ", "bar")       = false
StringUtils.isAllEmpty("foo", "bar")     = false

isAllLowerCase(CharSequence cs) 檢查字符串中全部字符是不是小寫，返回一個boolean

isAllUpperCase(CharSequence cs) 檢查字符串中全部字符是不是大寫，返回一個boolean

isAnyBlank(CharSequence... css) 檢查數組中字符串是否有一個爲null、empty或全是空格字符，返回一個boolean

StringUtils.isAnyBlank(null)             = true
StringUtils.isAnyBlank(null, "foo")      = true
StringUtils.isAnyBlank(null, null)       = true
StringUtils.isAnyBlank("", "bar")        = true
StringUtils.isAnyBlank("bob", "")        = true
StringUtils.isAnyBlank("  bob  ", null)  = true
StringUtils.isAnyBlank(" ", "bar")       = true
StringUtils.isAnyBlank(new String[] {})  = false
StringUtils.isAnyBlank(new String[]{""}) = true
StringUtils.isAnyBlank("foo", "bar")     = false

isAnyEmpty(CharSequence... css) 檢查數組中字符串是否有一個爲null、empty，返回一個boolean

StringUtils.isAnyEmpty(null)             = true
StringUtils.isAnyEmpty(null, "foo")      = true
StringUtils.isAnyEmpty("", "bar")        = true
StringUtils.isAnyEmpty("bob", "")        = true
StringUtils.isAnyEmpty("  bob  ", null)  = true
StringUtils.isAnyEmpty(" ", "bar")       = false
StringUtils.isAnyEmpty("foo", "bar")     = false
StringUtils.isAnyEmpty(new String[]{})   = false
StringUtils.isAnyEmpty(new String[]{""}) = true

isBlank(CharSequence cs) 檢查字符串是否爲null、empty或空格字符，返回一個boolean

StringUtils.isBlank(null)      = true
StringUtils.isBlank("")        = true
StringUtils.isBlank(" ")       = true
StringUtils.isBlank("bob")     = false
StringUtils.isBlank("  bob  ") = false

isEmpty(CharSequence cs) 檢查字符串是否爲null、empty，返回一個boolean

StringUtils.isEmpty(null)      = true
StringUtils.isEmpty("")        = true
StringUtils.isEmpty(" ")       = false
StringUtils.isEmpty("bob")     = false
StringUtils.isEmpty("  bob  ") = false

isNotBlank(CharSequence cs) 檢查字符串是否不爲null、empty或空格字符，返回一個boolean

isNotEmpty(CharSequence cs) 檢查字符串是否不爲null、empty，返回一個boolean

isNumeric(CharSequence cs) 檢查字符串是不是數字，返回一個boolean

StringUtils.isNumeric(null)   = false
StringUtils.isNumeric("")     = false
StringUtils.isNumeric("  ")   = false
StringUtils.isNumeric("123")  = true
StringUtils.isNumeric("१२३")  = true
StringUtils.isNumeric("12 3") = false
StringUtils.isNumeric("ab2c") = false
StringUtils.isNumeric("12-3") = false
StringUtils.isNumeric("12.3") = false
StringUtils.isNumeric("-123") = false
StringUtils.isNumeric("+123") = false

isWhitespace(CharSequence cs) 檢查字符串是不是空格字符，返回一個boolean

StringUtils.isWhitespace(null)   = false
StringUtils.isWhitespace("")     = true
StringUtils.isWhitespace("  ")   = true
StringUtils.isWhitespace("abc")  = false
StringUtils.isWhitespace("ab2c") = false
StringUtils.isWhitespace("ab-c") = false

join(byte[] array, char separator) 將字節數組轉換成string，以指定字符分隔

StringUtils.join(null, *)               = null
StringUtils.join([], *)                 = ""
StringUtils.join([null], *)             = ""
StringUtils.join([1, 2, 3], ';')  = "1;2;3"
StringUtils.join([1, 2, 3], null) = "123"

char、double、float、int、long、short、object、T同理

joinWith(String separator, Object... objects) 將多個元素已指定字符分隔拼接成String

StringUtils.joinWith(",", {"a", "b"})        = "a,b"
StringUtils.joinWith(",", {"a", "b",""})     = "a,b,"
StringUtils.joinWith(",", {"a", null, "b"})  = "a,,b"
StringUtils.joinWith(null, {"a", "b"})       = "ab"

lastIndexOf(CharSequence seq, CharSequence searchSeq) 獲取指定字符在字符串中的最後一個索引位置

StringUtils.lastIndexOf(null, *)          = -1
StringUtils.lastIndexOf(*, null)          = -1
StringUtils.lastIndexOf("", "")           = 0
StringUtils.lastIndexOf("aabaabaa", "a")  = 7
StringUtils.lastIndexOf("aabaabaa", "b")  = 5
StringUtils.lastIndexOf("aabaabaa", "ab") = 4
StringUtils.lastIndexOf("aabaabaa", "")   = 8

left(String str, int len) 返回從左邊開始指定大小的字符串

StringUtils.left(null, *)    = null
StringUtils.left(*, -ve)     = ""
StringUtils.left("", *)      = ""
StringUtils.left("abc", 0)   = ""
StringUtils.left("abc", 2)   = "ab"
StringUtils.left("abc", 4)   = "abc"

right(String str, int len) 同上相反

length(CharSequence cs) 獲取字符串大小，返回一個int

lowerCase(String str) 將字符串轉換爲小寫，返回一個string

StringUtils.lowerCase(null)  = null
StringUtils.lowerCase("")    = ""
StringUtils.lowerCase("aBc") = "abc"

upperCase(String str) 同上相反

mid(String str, int pos, int len) 獲取字符串指定位置區間的字符，返回一個string

StringUtils.mid(null, *, *)    = null
StringUtils.mid(*, *, -ve)     = ""
StringUtils.mid("", 0, *)      = ""
StringUtils.mid("abc", 0, 2)   = "ab"
StringUtils.mid("abc", 0, 4)   = "abc"
StringUtils.mid("abc", 2, 4)   = "c"
StringUtils.mid("abc", 4, 2)   = ""
StringUtils.mid("abc", -2, 2)  = "ab"

overlay(String str, String overlay, int start, int end) 在字符串位置區間插入指定字符，返回一個string

StringUtils.overlay(null, *, *, *)            = null
StringUtils.overlay("", "abc", 0, 0)          = "abc"
StringUtils.overlay("abcdef", null, 2, 4)     = "abef"
StringUtils.overlay("abcdef", "", 2, 4)       = "abef"
StringUtils.overlay("abcdef", "", 4, 2)       = "abef"
StringUtils.overlay("abcdef", "zzzz", 2, 4)   = "abzzzzef"
StringUtils.overlay("abcdef", "zzzz", 4, 2)   = "abzzzzef"
StringUtils.overlay("abcdef", "zzzz", -1, 4)  = "zzzzef"
StringUtils.overlay("abcdef", "zzzz", 2, 8)   = "abzzzz"
StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
StringUtils.overlay("abcdef", "zzzz", 8, 10)  = "abcdefzzzz"

prependIfMissing(String str, CharSequence prefix, CharSequence... prefixes) 在字符串最左邊插入指定字符，若是已存在，將不插入，返回一個string

StringUtils.prependIfMissing(null, null) = null
StringUtils.prependIfMissing("abc", null) = "abc"
StringUtils.prependIfMissing("", "xyz") = "xyz"
StringUtils.prependIfMissing("abc", "xyz") = "xyzabc"
StringUtils.prependIfMissing("xyzabc", "xyz") = "xyzabc"
StringUtils.prependIfMissing("XYZabc", "xyz") = "xyzXYZabc"

prependIfMissingIgnoreCase(String str, CharSequence prefix, CharSequence... prefixes) 同上，只是不區分大小寫

remove(String str, char remove) 刪除字符串中指定字符，返回一個string

StringUtils.remove(null, *)       = null
StringUtils.remove("", *)         = ""
StringUtils.remove("queued", 'u') = "qeed"
StringUtils.remove("queued", 'z') = "queued"

removeIgnoreCase(String str, String remove) 同上，只是不區分大小寫

removeAll(String text, String regex) 根據匹配規則刪除全部字符，返回一個string

StringUtils.removeAll(null, *)      = null
StringUtils.removeAll("any", null)  = "any"
StringUtils.removeAll("any", "")    = "any"
StringUtils.removeAll("any", ".*")  = ""
StringUtils.removeAll("any", ".+")  = ""
StringUtils.removeAll("abc", ".?")  = ""
StringUtils.removeAll("A<__>\n<__>B", "<.*>")      = "A\nB"
StringUtils.removeAll("A<__>\n<__>B", "(?s)<.*>")  = "AB"
StringUtils.removeAll("ABCabc123abc", "[a-z]")     = "ABC123"

removeEnd(String str, String remove) 刪除字符串結尾指定字符，返回一個string

StringUtils.removeEnd(null, *)      = null
StringUtils.removeEnd("", *)        = ""
StringUtils.removeEnd(*, null)      = *
StringUtils.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
StringUtils.removeEnd("www.domain.com", ".com")   = "www.domain"
StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
StringUtils.removeEnd("abc", "")    = "abc"

removeStart(String str, String remove) 同上相反

removeEndIgnoreCase(String str, String remove) 同上，只是不區分大小寫

removeFirst(String text, String regex) 根據匹配規則刪除第一次出現的字符，返回一個string

StringUtils.removeFirst(null, *)      = null
StringUtils.removeFirst("any", null)  = "any"
StringUtils.removeFirst("any", "")    = "any"
StringUtils.removeFirst("any", ".*")  = ""
StringUtils.removeFirst("any", ".+")  = ""
StringUtils.removeFirst("abc", ".?")  = "bc"
StringUtils.removeFirst("A<__>\n<__>B", "<.*>")      = "A\n<__>B"
StringUtils.removeFirst("A<__>\n<__>B", "(?s)<.*>")  = "AB"
StringUtils.removeFirst("ABCabc123", "[a-z]")          = "ABCbc123"
StringUtils.removeFirst("ABCabc123abc", "[a-z]+")      = "ABC123abc"

repeat(String str, int repeat) 將字符重複指定次數拼接成新的字符串，返回一個string

StringUtils.repeat(null, 2) = null
StringUtils.repeat("", 0)   = ""
StringUtils.repeat("", 2)   = ""
StringUtils.repeat("a", 3)  = "aaa"
StringUtils.repeat("ab", 2) = "abab"
StringUtils.repeat("a", -2) = ""

replace(String text, String searchString, String replacement) 用replacement替換字符串中的全部searchString，返回一個string

StringUtils.replace(null, *, *)        = null
StringUtils.replace("", *, *)          = ""
StringUtils.replace("any", null, *)    = "any"
StringUtils.replace("any", *, null)    = "any"
StringUtils.replace("any", "", *)      = "any"
StringUtils.replace("aba", "a", null)  = "aba"
StringUtils.replace("aba", "a", "")    = "b"
StringUtils.replace("aba", "a", "z")   = "zbz"

reverse(String str) 將字符串反轉，返回一個string

StringUtils.reverse(null)  = null
StringUtils.reverse("")    = ""
StringUtils.reverse("bat") = "tab"

reverseDelimited(String str, char separatorChar) 將字符串指定分隔符出的字符反轉

StringUtils.reverseDelimited(null, *)      = null
 StringUtils.reverseDelimited("", *)        = ""
 StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
 StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"

split(String str, String separatorChars) 將字符串以指定字符分隔，返回數組

StringUtils.split(null, *)         = null
StringUtils.split("", *)           = []
StringUtils.split("abc def", null) = ["abc", "def"]
StringUtils.split("abc def", " ")  = ["abc", "def"]
StringUtils.split("abc  def", " ") = ["abc", "def"]
StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]

substring(String str, int start) 將字符串從指定位置區間截取，返回string

swapCase(String str) 將字符串大小寫互轉，返回一個string

StringUtils.swapCase(null)                 = null
StringUtils.swapCase("")                   = ""
StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"

toEncodedString(byte[] bytes, Charset charset) 將字符串轉爲指定編碼格式，返回一個string

trim(String str) 去除字符串空格

trimToEmpty(String str) 去除字符串空格，null轉爲empty，返回一個string

StringUtils.trimToEmpty(null)          = ""
StringUtils.trimToEmpty("")            = ""
StringUtils.trimToEmpty("     ")       = ""
StringUtils.trimToEmpty("abc")         = "abc"
StringUtils.trimToEmpty("    abc    ") = "abc"