java.lang.Object

cloud.opencode.base.string.OpenString

public final class OpenString extends Object

Enhanced String Utility Facade 字符串增强工具门面类

Provides comprehensive string operations including padding, truncation, transformation, etc.

提供全面的字符串操作，包括填充、截断、转换等。

Features | 主要功能:

Padding and truncation - 填充和截断
Case conversion - 大小写转换
String manipulation - 字符串操作
Substring extraction - 子串提取
Validation and checking - 验证和检查

Usage Examples | 使用示例:

// Padding
String padded = OpenString.padLeft("42", 5, '0'); // "00042"

// Truncation
String truncated = OpenString.truncate("Hello World", 8); // "Hello..."

// Substring extraction
String between = OpenString.substringBetween("[hello]", "[", "]"); // "hello"

// Statistics
int count = OpenString.countMatches("banana", "an"); // 2

Security | 安全性:

Thread-safe: Yes (stateless utility) - 线程安全: 是（无状态工具类）
Null-safe: Yes - 空值安全: 是

Since:

JDK 25, opencode-base-string V1.0.0

Author:

Leon Soo www.LeonSoo.com

See Also:

Method Summary

Modifier and Type

Method

Description

static String

abbreviate(String str, int maxWidth)

Abbreviate a string using ellipsis ("...") if it exceeds the maximum width.

static String

abbreviate(String str, int offset, int maxWidth)

Abbreviate a string using ellipsis ("...") starting from an offset.

static String

abbreviateMiddle(String str, String middle, int maxLength)

static String

blankToNull(String str)

Convert a blank string (null, empty, or whitespace only) to null.

static String

capitalize(String str)

static String

center(String str, int minLength, char padChar)

Center string within the given minimum length using the pad character.

static Map<Character, Integer>

charFrequency(String str)

static String

chomp(String str)

static String

chop(String str)

static String

commonPrefix(String... strs)

static String

commonSuffix(String... strs)

static boolean

containsAny(String str, CharSequence... searchStrings)

Check if a string contains any of the given search strings.

static boolean

containsChinese(String str)

static boolean

containsIgnoreCase(String str, String search)

Check if a string contains another string, ignoring case.

static boolean

containsNone(String str, String invalidChars)

Check if a string contains none of the given invalid characters.

static boolean

containsOnly(String str, String validChars)

Check if a string contains only the given valid characters.

static int

countMatches(String str, char ch)

static int

countMatches(String str, String subStr)

static String

defaultIfBlank(String str, String defaultStr)

static String

defaultIfEmpty(String str, String defaultStr)

static String

difference(String str1, String str2)

static String

emptyToNull(String str)

Convert an empty string to null.

static boolean

endsWithAny(String str, String... suffixes)

Check if a string ends with any of the given suffixes.

static boolean

endsWithIgnoreCase(String str, String suffix)

Check if a string ends with a suffix, ignoring case.

static String

ensurePrefix(String str, String prefix)

static String

ensureSuffix(String str, String suffix)

static String

ensureWrap(String str, String wrap)

static List<Integer>

findAll(String str, String subStr)

static String

firstNonBlank(String... strs)

static String

firstNonEmpty(String... strs)

static String

format(String pattern, Object... args)

Format a string using SLF4J-style {} placeholders.

static String

getDigits(String str)

static String

getRepeatedPattern(String str)

static int

indexOfDifference(String str1, String str2)

static int

indexOfNth(String str, String subStr, int n)

static boolean

isAllChinese(String str)

static boolean

isAllLowerCase(String str)

static boolean

isAllUpperCase(String str)

static boolean

isAlpha(String str)

static boolean

isAlphanumeric(String str)

static boolean

isAscii(String str)

static boolean

isBlank(String str)

Check if a string is blank (null, empty, or whitespace only).

static boolean

isEmpty(String str)

Check if a string is empty (null or zero length).

static boolean

isMixedCase(String str)

static boolean

isNotBlank(String str)

Check if a string is not blank.

static boolean

isNotEmpty(String str)

Check if a string is not empty.

static boolean

isNumeric(String str)

static boolean

isPalindrome(String str)

static boolean

isPalindromeIgnoreCase(String str)

static boolean

isRepeated(String str)

static String

join(String separator, Object... elements)

Join elements with a separator.

static String

joinSkipBlanks(String separator, CharSequence... elements)

Join elements with a separator, skipping blank elements.

static String

joinSkipNulls(String separator, Object... elements)

Join elements with a separator, skipping null elements.

static String

keepAlphanumeric(String str)

static String

keepChinese(String str)

static String

keepDigits(String str)

static String

keepLetters(String str)

static int

lastIndexOfNth(String str, String subStr, int n)

static String

left(String str, int length)

Get the leftmost length characters of a string.

static String

mid(String str, int start, int end)

static String

normalizeWhitespace(String str)

static String

nullToEmpty(String str)

Convert a null string to an empty string.

static String

padLeft(String str, int minLength, char padChar)

Pad string on the left to reach minimum length.

static String

padRight(String str, int minLength, char padChar)

Pad string on the right to reach minimum length.

static String

removeInvisibleChars(String str)

static String

removePrefix(String str, String prefix)

static String

removePrefixIgnoreCase(String str, String prefix)

Remove a prefix from a string, ignoring case.

static String

removeSpecialChars(String str)

static String

removeSuffix(String str, String suffix)

static String

removeSuffixIgnoreCase(String str, String suffix)

Remove a suffix from a string, ignoring case.

static String

removeWhitespace(String str)

static String

repeat(String str, String separator, int count)

Repeat a string with a separator between each occurrence.

static String

replaceEach(String text, String[] searchList, String[] replacementList)

Replace all occurrences of search strings with corresponding replacement strings in a single pass.

static String

reverse(String str)

static String

right(String str, int length)

Get the rightmost length characters of a string.

static String

rotate(String str, int shift)

static String

shuffle(String str)

static String

shuffle(String str, Random random)

static List<String>

split(String str, String separator)

Split a string by separator, returning a List.

static Map<String,String>

splitToMap(String str, String entrySep, String kvSep)

Split a string into a key-value map using entry and key-value separators.

static boolean

startsWithAny(String str, String... prefixes)

Check if a string starts with any of the given prefixes.

static boolean

startsWithIgnoreCase(String str, String prefix)

Check if a string starts with a prefix, ignoring case.

static String

stripAccents(String str)

static String

substringAfter(String str, String separator)

static String

substringAfterLast(String str, String separator)

static String

substringBefore(String str, String separator)

static String

substringBeforeLast(String str, String separator)

static String

substringBetween(String str, String open, String close)

static String[]

substringsBetween(String str, String open, String close)

static String

swapCase(String str)

static String

toTitleCase(String str)

static String

truncate(String str, int maxLength)

static String

truncate(String str, int maxLength, String ellipsis)

static String

truncateByBytes(String str, int maxBytes, String charset)

static String

truncateMiddle(String str, int maxLength)

static String

uncapitalize(String str)

static String

unwrap(String str, char wrapChar)

static String

unwrap(String str, String wrapStr)

static Map<String,Integer>

wordFrequency(String str)

static String

wrap(String str, char wrapChar)

static String

wrap(String str, String wrapStr)

Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details
- padLeft
  
  public static String padLeft(String str, int minLength, char padChar)
  
  Pad string on the left to reach minimum length. 在字符串左侧填充以达到最小长度。
  
  Parameters:
  
  str - the input string, may be null (returns null if so)
  
  minLength - the minimum desired length; must not be negative
  
  padChar - the character to pad with
  
  Returns:
  
  the padded string, or null if input was null
  
  Throws:
  
  IllegalArgumentException - if minLength is negative
- padRight
  
  public static String padRight(String str, int minLength, char padChar)
  
  Pad string on the right to reach minimum length. 在字符串右侧填充以达到最小长度。
  
  Parameters:
  
  str - the input string, may be null (returns null if so)
  
  minLength - the minimum desired length; must not be negative
  
  padChar - the character to pad with
  
  Returns:
  
  the padded string, or null if input was null
  
  Throws:
  
  IllegalArgumentException - if minLength is negative
- center
  
  public static String center(String str, int minLength, char padChar)
  
  Center string within the given minimum length using the pad character. 使用填充字符将字符串居中至给定的最小长度。
  
  Parameters:
  
  str - the input string, may be null (returns null if so)
  
  minLength - the minimum desired length; must not be negative
  
  padChar - the character to pad with
  
  Returns:
  
  the centered string, or null if input was null
  
  Throws:
  
  IllegalArgumentException - if minLength is negative
- left
  
  public static String left(String str, int length)
  
  Get the leftmost length characters of a string. 获取字符串最左侧的 length 个字符。
  
  Parameters:
  
  str - the input string, may be null (returns null if so)
  
  length - the number of characters to extract; negative values return null input unchanged
  
  Returns:
  
  the leftmost characters, or null if input was null
- right
  
  public static String right(String str, int length)
  
  Get the rightmost length characters of a string. 获取字符串最右侧的 length 个字符。
  
  Parameters:
  
  str - the input string, may be null (returns null if so)
  
  length - the number of characters to extract; negative values return null input unchanged
  
  Returns:
  
  the rightmost characters, or null if input was null
- mid
  
  public static String mid(String str, int start, int end)
- truncate
  
  public static String truncate(String str, int maxLength)
- truncate
  
  public static String truncate(String str, int maxLength, String ellipsis)
- truncateMiddle
  
  public static String truncateMiddle(String str, int maxLength)
- truncateByBytes
  
  public static String truncateByBytes(String str, int maxBytes, String charset)
- capitalize
  
  public static String capitalize(String str)
- uncapitalize
  
  public static String uncapitalize(String str)
- swapCase
  
  public static String swapCase(String str)
- toTitleCase
  
  public static String toTitleCase(String str)
- reverse
  
  public static String reverse(String str)
- shuffle
  
  public static String shuffle(String str)
- shuffle
  
  public static String shuffle(String str, Random random)
- countMatches
  
  public static int countMatches(String str, String subStr)
- countMatches
  
  public static int countMatches(String str, char ch)
- charFrequency
  
  public static Map<Character, Integer> charFrequency(String str)
- wordFrequency
  
  public static Map<String,Integer> wordFrequency(String str)
- removeWhitespace
  
  public static String removeWhitespace(String str)
- normalizeWhitespace
  
  public static String normalizeWhitespace(String str)
- removeInvisibleChars
  
  public static String removeInvisibleChars(String str)
- removeSpecialChars
  
  public static String removeSpecialChars(String str)
- keepDigits
  
  public static String keepDigits(String str)
- keepLetters
  
  public static String keepLetters(String str)
- keepAlphanumeric
  
  public static String keepAlphanumeric(String str)
- keepChinese
  
  public static String keepChinese(String str)
- isNumeric
  
  public static boolean isNumeric(String str)
- isAlpha
  
  public static boolean isAlpha(String str)
- isAlphanumeric
  
  public static boolean isAlphanumeric(String str)
- isAscii
  
  public static boolean isAscii(String str)
- containsChinese
  
  public static boolean containsChinese(String str)
- isAllChinese
  
  public static boolean isAllChinese(String str)
- isAllLowerCase
  
  public static boolean isAllLowerCase(String str)
- isAllUpperCase
  
  public static boolean isAllUpperCase(String str)
- isMixedCase
  
  public static boolean isMixedCase(String str)
- isPalindrome
  
  public static boolean isPalindrome(String str)
- isPalindromeIgnoreCase
  
  public static boolean isPalindromeIgnoreCase(String str)
- ensurePrefix
  
  public static String ensurePrefix(String str, String prefix)
- ensureSuffix
  
  public static String ensureSuffix(String str, String suffix)
- ensureWrap
  
  public static String ensureWrap(String str, String wrap)
- removePrefix
  
  public static String removePrefix(String str, String prefix)
- removeSuffix
  
  public static String removeSuffix(String str, String suffix)
- commonPrefix
  
  public static String commonPrefix(String... strs)
- commonSuffix
  
  public static String commonSuffix(String... strs)
- findAll
  
  public static List<Integer> findAll(String str, String subStr)
- indexOfNth
  
  public static int indexOfNth(String str, String subStr, int n)
- lastIndexOfNth
  
  public static int lastIndexOfNth(String str, String subStr, int n)
- substringBefore
  
  public static String substringBefore(String str, String separator)
- substringAfter
  
  public static String substringAfter(String str, String separator)
- substringBeforeLast
  
  public static String substringBeforeLast(String str, String separator)
- substringAfterLast
  
  public static String substringAfterLast(String str, String separator)
- substringBetween
  
  public static String substringBetween(String str, String open, String close)
- substringsBetween
  
  public static String[] substringsBetween(String str, String open, String close)
- wrap
  
  public static String wrap(String str, char wrapChar)
- wrap
  
  public static String wrap(String str, String wrapStr)
- unwrap
  
  public static String unwrap(String str, char wrapChar)
- unwrap
  
  public static String unwrap(String str, String wrapStr)
- chomp
  
  public static String chomp(String str)
- chop
  
  public static String chop(String str)
- stripAccents
  
  public static String stripAccents(String str)
- getDigits
  
  public static String getDigits(String str)
- rotate
  
  public static String rotate(String str, int shift)
- difference
  
  public static String difference(String str1, String str2)
- indexOfDifference
  
  public static int indexOfDifference(String str1, String str2)
- abbreviateMiddle
  
  public static String abbreviateMiddle(String str, String middle, int maxLength)
- isRepeated
  
  public static boolean isRepeated(String str)
- getRepeatedPattern
  
  public static String getRepeatedPattern(String str)
- defaultIfBlank
  
  public static String defaultIfBlank(String str, String defaultStr)
- defaultIfEmpty
  
  public static String defaultIfEmpty(String str, String defaultStr)
- firstNonBlank
  
  public static String firstNonBlank(String... strs)
- firstNonEmpty
  
  public static String firstNonEmpty(String... strs)
- isBlank
  public static boolean isBlank(String str)
  
  Check if a string is blank (null, empty, or whitespace only). 检查字符串是否为空白（null、空字符串或仅包含空白字符）。
  Examples | 示例:
  
  isBlank(null) = true isBlank("") = true isBlank(" ") = true isBlank("abc") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  Returns:
  
  true if the string is null, empty, or whitespace only | 如果字符串为null、空或仅含空白则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- isNotBlank
  public static boolean isNotBlank(String str)
  
  Check if a string is not blank. 检查字符串是否不为空白。
  Examples | 示例:
  
  isNotBlank(null) = false isNotBlank("") = false isNotBlank(" ") = false isNotBlank("abc") = true
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  Returns:
  
  true if the string is not null, not empty, and not whitespace only | 如果字符串非null、非空且非纯空白则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- isEmpty
  public static boolean isEmpty(String str)
  
  Check if a string is empty (null or zero length). 检查字符串是否为空（null或长度为零）。
  Examples | 示例:
  
  isEmpty(null) = true isEmpty("") = true isEmpty(" ") = false isEmpty("abc") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  Returns:
  
  true if the string is null or empty | 如果字符串为null或空则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- isNotEmpty
  public static boolean isNotEmpty(String str)
  
  Check if a string is not empty. 检查字符串是否不为空。
  Examples | 示例:
  
  isNotEmpty(null) = false isNotEmpty("") = false isNotEmpty(" ") = true isNotEmpty("abc") = true
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  Returns:
  
  true if the string is not null and not empty | 如果字符串非null且非空则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- containsAny
  public static boolean containsAny(String str, CharSequence... searchStrings)
  
  Check if a string contains any of the given search strings. 检查字符串是否包含给定搜索字符串中的任意一个。
  Examples | 示例:
  
  containsAny("hello world", "world", "foo") = true containsAny("hello", "foo", "bar") = false containsAny(null, "foo") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  searchStrings - the strings to search for | 要搜索的字符串
  
  Returns:
  
  true if the string contains any of the search strings | 如果字符串包含任一搜索字符串则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- containsNone
  public static boolean containsNone(String str, String invalidChars)
  
  Check if a string contains none of the given invalid characters. 检查字符串是否不包含任何给定的无效字符。
  Examples | 示例:
  
  containsNone("hello", "xyz") = true containsNone("hello", "hxyz") = false containsNone(null, "xyz") = true
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  invalidChars - characters that should not appear | 不应出现的字符
  
  Returns:
  
  true if the string contains none of the invalid characters | 如果字符串不包含任何无效字符则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- containsOnly
  public static boolean containsOnly(String str, String validChars)
  
  Check if a string contains only the given valid characters. 检查字符串是否仅包含给定的有效字符。
  Examples | 示例:
  
  containsOnly("aab", "abc") = true containsOnly("abd", "abc") = false containsOnly(null, "abc") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  validChars - characters that are allowed | 允许的字符
  
  Returns:
  
  true if the string contains only valid characters | 如果字符串仅包含有效字符则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- containsIgnoreCase
  public static boolean containsIgnoreCase(String str, String search)
  
  Check if a string contains another string, ignoring case. 忽略大小写检查字符串是否包含另一个字符串。
  Examples | 示例:
  
  containsIgnoreCase("Hello World", "hello") = true containsIgnoreCase("Hello World", "foo") = false containsIgnoreCase(null, "hello") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  search - the string to search for, may be null | 要搜索的字符串，可为 null
  
  Returns:
  
  true if the string contains the search string ignoring case | 如果忽略大小写后字符串包含搜索字符串则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- startsWithAny
  public static boolean startsWithAny(String str, String... prefixes)
  
  Check if a string starts with any of the given prefixes. 检查字符串是否以给定前缀中的任意一个开头。
  Examples | 示例:
  
  startsWithAny("hello", "he", "ho") = true startsWithAny("hello", "foo") = false startsWithAny(null, "he") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  prefixes - the prefixes to check | 要检查的前缀
  
  Returns:
  
  true if the string starts with any of the prefixes | 如果字符串以任一前缀开头则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- endsWithAny
  public static boolean endsWithAny(String str, String... suffixes)
  
  Check if a string ends with any of the given suffixes. 检查字符串是否以给定后缀中的任意一个结尾。
  Examples | 示例:
  
  endsWithAny("hello", "lo", "la") = true endsWithAny("hello", "foo") = false endsWithAny(null, "lo") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  suffixes - the suffixes to check | 要检查的后缀
  
  Returns:
  
  true if the string ends with any of the suffixes | 如果字符串以任一后缀结尾则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- startsWithIgnoreCase
  public static boolean startsWithIgnoreCase(String str, String prefix)
  
  Check if a string starts with a prefix, ignoring case. 忽略大小写检查字符串是否以指定前缀开头。
  Examples | 示例:
  
  startsWithIgnoreCase("Hello", "he") = true startsWithIgnoreCase("Hello", "HE") = true startsWithIgnoreCase("Hello", "foo") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  prefix - the prefix to check, may be null | 要检查的前缀，可为 null
  
  Returns:
  
  true if the string starts with the prefix ignoring case | 如果忽略大小写后字符串以该前缀开头则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- endsWithIgnoreCase
  public static boolean endsWithIgnoreCase(String str, String suffix)
  
  Check if a string ends with a suffix, ignoring case. 忽略大小写检查字符串是否以指定后缀结尾。
  Examples | 示例:
  
  endsWithIgnoreCase("Hello", "LO") = true endsWithIgnoreCase("Hello", "lo") = true endsWithIgnoreCase("Hello", "foo") = false
  
  Parameters:
  
  str - the string to check, may be null | 待检查的字符串，可为 null
  
  suffix - the suffix to check, may be null | 要检查的后缀，可为 null
  
  Returns:
  
  true if the string ends with the suffix ignoring case | 如果忽略大小写后字符串以该后缀结尾则返回true
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- replaceEach
  public static String replaceEach(String text, String[] searchList, String[] replacementList)
  
  Replace all occurrences of search strings with corresponding replacement strings in a single pass. 单趟扫描替换所有搜索字符串为对应的替换字符串，不递归替换。
  This method scans the input text once and replaces each occurrence of a search string with the corresponding replacement. Replacements are not applied recursively.
  
  本方法对输入文本进行单趟扫描，将每个搜索字符串替换为对应的替换字符串。替换不会递归应用。
  
  Examples | 示例:
  
  replaceEach("aabbcc", new String[]{"aa","bb"}, new String[]{"11","22"}) = "1122cc" replaceEach("abcde", new String[]{"ab","d"}, new String[]{"w","t"}) = "wcte"
  
  Parameters:
  
  text - the text to search and replace in, may be null | 要搜索替换的文本，可为 null
  
  searchList - the strings to search for, may be null | 要搜索的字符串数组，可为 null
  
  replacementList - the strings to replace them with, may be null | 替换字符串数组，可为 null
  
  Returns:
  
  the text with replacements applied, or original text if no replacements needed | 替换后的文本
  
  Throws:
  
  IllegalArgumentException - if searchList and replacementList have different lengths | 如果搜索和替换数组长度不同
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- format
  public static String format(String pattern, Object... args)
  
  Format a string using SLF4J-style {} placeholders. 使用SLF4J风格的 {} 占位符格式化字符串。
  Placeholders are replaced left-to-right with the provided arguments. Use \{} to escape a placeholder (outputs literal {}). Excess arguments are ignored; insufficient arguments leave placeholders intact.
  
  占位符从左到右依次替换为提供的参数。使用 \{} 转义占位符（输出字面量 {}）。多余参数被忽略；参数不足时保留未替换的占位符。
  
  Examples | 示例:
  
  format("{} has {} items", "Alice", 3) = "Alice has 3 items" format("{} and {}", "A") = "A and {}" format("literal \\{}", "ignored") = "literal {}"
  
  Parameters:
  
  pattern - the pattern string with {} placeholders, may be null | 包含占位符的模式字符串，可为 null
  
  args - the arguments to fill in placeholders | 用于填充占位符的参数
  
  Returns:
  
  the formatted string, or null if pattern is null | 格式化后的字符串，pattern为null时返回null
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- nullToEmpty
  public static String nullToEmpty(String str)
  
  Convert a null string to an empty string. 将 null 字符串转换为空字符串。
  Examples | 示例:
  
  nullToEmpty(null) = "" nullToEmpty("") = "" nullToEmpty("hello") = "hello"
  
  Parameters:
  
  str - the string, may be null | 字符串，可为 null
  
  Returns:
  
  the original string or empty string if null | 原字符串或null时返回空字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- emptyToNull
  public static String emptyToNull(String str)
  
  Convert an empty string to null. 将空字符串转换为 null。
  Examples | 示例:
  
  emptyToNull("") = null emptyToNull(null) = null emptyToNull("hello") = "hello" emptyToNull(" ") = " "
  
  Parameters:
  
  str - the string, may be null | 字符串，可为 null
  
  Returns:
  
  null if the string is empty, otherwise the original string | 字符串为空时返回null，否则返回原字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- blankToNull
  public static String blankToNull(String str)
  
  Convert a blank string (null, empty, or whitespace only) to null. 将空白字符串（null、空字符串或仅含空白字符）转换为 null。
  Examples | 示例:
  
  blankToNull("") = null blankToNull(" ") = null blankToNull(null) = null blankToNull("hello") = "hello"
  
  Parameters:
  
  str - the string, may be null | 字符串，可为 null
  
  Returns:
  
  null if the string is blank, otherwise the original string | 字符串为空白时返回null，否则返回原字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- repeat
  public static String repeat(String str, String separator, int count)
  
  Repeat a string with a separator between each occurrence. 使用分隔符重复字符串。
  Examples | 示例:
  
  repeat("abc", ", ", 3) = "abc, abc, abc" repeat("x", "-", 1) = "x" repeat("x", "-", 0) = "" repeat(null, "-", 3) = null
  
  Parameters:
  
  str - the string to repeat, may be null | 要重复的字符串，可为 null
  
  separator - the separator between repetitions | 重复之间的分隔符
  
  count - the number of repetitions; <= 0 returns empty string | 重复次数；小于等于0返回空字符串
  
  Returns:
  
  the repeated string with separators, or null if str is null | 带分隔符的重复字符串，str为null时返回null
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- removePrefixIgnoreCase
  public static String removePrefixIgnoreCase(String str, String prefix)
  
  Remove a prefix from a string, ignoring case. 忽略大小写移除字符串的前缀。
  Examples | 示例:
  
  removePrefixIgnoreCase("HelloWorld", "hello") = "World" removePrefixIgnoreCase("HelloWorld", "HELLO") = "World" removePrefixIgnoreCase("HelloWorld", "foo") = "HelloWorld"
  
  Parameters:
  
  str - the string, may be null | 字符串，可为 null
  
  prefix - the prefix to remove, may be null | 要移除的前缀，可为 null
  
  Returns:
  
  the string without the prefix, or original if no match | 移除前缀后的字符串，不匹配时返回原字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- removeSuffixIgnoreCase
  public static String removeSuffixIgnoreCase(String str, String suffix)
  
  Remove a suffix from a string, ignoring case. 忽略大小写移除字符串的后缀。
  Examples | 示例:
  
  removeSuffixIgnoreCase("HelloWorld", "world") = "Hello" removeSuffixIgnoreCase("HelloWorld", "WORLD") = "Hello" removeSuffixIgnoreCase("HelloWorld", "foo") = "HelloWorld"
  
  Parameters:
  
  str - the string, may be null | 字符串，可为 null
  
  suffix - the suffix to remove, may be null | 要移除的后缀，可为 null
  
  Returns:
  
  the string without the suffix, or original if no match | 移除后缀后的字符串，不匹配时返回原字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- split
  public static List<String> split(String str, String separator)
  
  Split a string by separator, returning a List. Null-safe. 按分隔符分割字符串，返回 List。空值安全。
  Examples | 示例:
  
  split("a,b,c", ",") = ["a", "b", "c"] split(null, ",") = [] split("", ",") = [""]
  
  Parameters:
  
  str - the string to split, may be null | 要分割的字符串，可为 null
  
  separator - the separator string | 分隔符字符串
  
  Returns:
  
  a list of split parts, never null | 分割后的部分列表，不会返回 null
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- splitToMap
  public static Map<String,String> splitToMap(String str, String entrySep, String kvSep)
  
  Split a string into a key-value map using entry and key-value separators. 使用条目分隔符和键值分隔符将字符串分割为键值映射。
  Examples | 示例:
  
  splitToMap("a=1invalid input: '&b'=2", "invalid input: '&'", "=") = {a=1, b=2} splitToMap(null, "invalid input: '&'", "=") = {}
  
  Parameters:
  
  str - the string to split, may be null | 要分割的字符串，可为 null
  
  entrySep - the separator between entries | 条目之间的分隔符
  
  kvSep - the separator between key and value | 键值之间的分隔符
  
  Returns:
  
  a map of key-value pairs, never null | 键值对映射，不会返回 null
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- join
  public static String join(String separator, Object... elements)
  
  Join elements with a separator. 使用分隔符合并元素。
  Examples | 示例:
  
  join(", ", "a", "b", "c") = "a, b, c" join(", ", "a", null, "c") = "a, null, c"
  
  Parameters:
  
  separator - the separator string | 分隔符字符串
  
  elements - the elements to join | 要合并的元素
  
  Returns:
  
  the joined string | 合并后的字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- joinSkipNulls
  public static String joinSkipNulls(String separator, Object... elements)
  
  Join elements with a separator, skipping null elements. 使用分隔符合并元素，跳过 null 元素。
  Examples | 示例:
  
  joinSkipNulls(", ", "a", null, "c") = "a, c"
  
  Parameters:
  
  separator - the separator string | 分隔符字符串
  
  elements - the elements to join | 要合并的元素
  
  Returns:
  
  the joined string without null elements | 跳过null后合并的字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- joinSkipBlanks
  public static String joinSkipBlanks(String separator, CharSequence... elements)
  
  Join elements with a separator, skipping blank elements. 使用分隔符合并元素，跳过空白元素。
  Examples | 示例:
  
  joinSkipBlanks(", ", "a", "", " ", "c") = "a, c"
  
  Parameters:
  
  separator - the separator string | 分隔符字符串
  
  elements - the elements to join | 要合并的元素
  
  Returns:
  
  the joined string without blank elements | 跳过空白后合并的字符串
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- abbreviate
  public static String abbreviate(String str, int maxWidth)
  
  Abbreviate a string using ellipsis ("...") if it exceeds the maximum width. 当字符串超过最大宽度时使用省略号("...")进行简写。
  Examples | 示例:
  
  abbreviate("Hello World", 8) = "Hello..." abbreviate("Hi", 8) = "Hi" abbreviate(null, 8) = null
  
  Parameters:
  
  str - the string to abbreviate, may be null | 要简写的字符串，可为 null
  
  maxWidth - the maximum width; must be >= 4 | 最大宽度；必须 >= 4
  
  Returns:
  
  the abbreviated string | 简写后的字符串
  
  Throws:
  
  IllegalArgumentException - if maxWidth is less than 4 | 如果maxWidth小于4
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3
- abbreviate
  public static String abbreviate(String str, int offset, int maxWidth)
  
  Abbreviate a string using ellipsis ("...") starting from an offset. 从指定偏移位置开始使用省略号("...")简写字符串。
  If the offset is greater than 0 and the string needs abbreviation, the result may start with "..." to indicate truncation from the left.
  
  如果偏移量大于0且字符串需要简写，结果可能以"..."开头表示左侧被截断。
  
  Examples | 示例:
  
  abbreviate("Hello World Test", 0, 11) = "Hello Wo..." abbreviate("Hello World Test", 6, 11) = "...orld ..." abbreviate(null, 0, 8) = null
  
  Parameters:
  
  str - the string to abbreviate, may be null | 要简写的字符串，可为 null
  
  offset - the left edge of the source string; if positive and truncation is needed, prepends "..." | 源字符串的左边缘偏移
  
  maxWidth - the maximum width; must be >= 4 | 最大宽度；必须 >= 4
  
  Returns:
  
  the abbreviated string | 简写后的字符串
  
  Throws:
  
  IllegalArgumentException - if maxWidth is less than 4 | 如果maxWidth小于4
  
  Since:
  
  JDK 25, opencode-base-string V1.0.3

Class OpenString

Method Summary

Methods inherited from class Object

Method Details

padLeft

padRight

center

left

right

mid

truncate

truncate

truncateMiddle

truncateByBytes

capitalize

uncapitalize

swapCase

toTitleCase

reverse

shuffle

shuffle

countMatches

countMatches

charFrequency

wordFrequency

removeWhitespace

normalizeWhitespace

removeInvisibleChars

removeSpecialChars

keepDigits

keepLetters

keepAlphanumeric

keepChinese

isNumeric

isAlpha

isAlphanumeric

isAscii

containsChinese

isAllChinese

isAllLowerCase

isAllUpperCase

isMixedCase

isPalindrome

isPalindromeIgnoreCase

ensurePrefix

ensureSuffix

ensureWrap

removePrefix

removeSuffix

commonPrefix

commonSuffix

findAll

indexOfNth

lastIndexOfNth

substringBefore

substringAfter

substringBeforeLast

substringAfterLast

substringBetween

substringsBetween

wrap

wrap

unwrap

unwrap

chomp

chop

stripAccents

getDigits

rotate

difference

indexOfDifference

abbreviateMiddle

isRepeated

getRepeatedPattern

defaultIfBlank

defaultIfEmpty

firstNonBlank

firstNonEmpty

isBlank

isNotBlank