Apache Commons Lang Part I – String Functions
By admin on Jan 7, 2008 in Java, open source, Programming
Apache Commons Lang provides very generic, very reusable components for everyday use.
String manipulation – StringUtils, StringEscapeUtils, RandomStringUtils, Tokenizer, WordUtils.
StringUtils operations are null safe. As taken from the documentation,
- IsEmpty/IsBlank – checks if a String contains text
- Trim/Strip – removes leading and trailing whitespace
- Equals – compares two strings null-safe
- IndexOf/LastIndexOf/Contains – null-safe index-of checks
- IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut – index-of any of a set of Strings
- ContainsOnly/ContainsNone – does String contains only/none of these characters
- Substring/Left/Right/Mid – null-safe substring extractions
- SubstringBefore/SubstringAfter/SubstringBetween – substring extraction relative to other strings
- Split/Join – splits a String into an array of substrings and vice versa
- Remove/Delete – removes part of a String
- Replace/Overlay – Searches a String and replaces one String with another
- Chomp/Chop – removes the last part of a String
- LeftPad/RightPad/Center/Repeat – pads a String
- UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize – changes the case of a String
- CountMatches – counts the number of occurrences of one String in another
- IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable – checks the characters in a String
- DefaultString – protects against a null input String
- Reverse/ReverseDelimited – reverses a String
- Abbreviate – abbreviates a string using ellipsis
- Difference – compares two Strings and reports on their differences
- LevensteinDistance – the number of changes needed to change one String into another
E.g.
// StringUtils System.out.println(StringUtils.capitalize("abc")) ; System.out.println(StringUtils.uncapitalize("ABC")); System.out.println(StringUtils.abbreviate("Monday", 4)); System.out.println(StringUtils.center("abc", 7, null)); System.out.println(StringUtils.isAlpha("a")); System.out.println(StringUtils.isAlphanumeric("hkHKHik")); System.out.println(StringUtils.isWhitespace(" ")); System.out.println(StringUtils.isAlphaSpace("xxx yy")); System.out.println(StringUtils.isAlphanumericSpace("hkHKHikkhbkuh")); System.out.println(StringUtils.isAsciiPrintable("A")); System.out.println(StringUtils.isNumeric("23")); System.out.println(StringUtils.isNumericSpace("23 ")); System.out.println(StringUtils.isEmpty("")); System.out.println(StringUtils.trimToNull(" \t\r\n\b ")); System.out.println(StringUtils.trimToEmpty(" \t\r\n\b ")); System.out.println(StringUtils.strip(" ")); System.out.println(StringUtils.isBlank(" foo "));
The output
Abc aBC M... abc true true true true true true true true true null false
StringEscapeUtils escapes and unescapes Strings for Java, Java Script, HTML, XML, and SQL.
E.g.
// StringEscapeUtils System.out.println( StringEscapeUtils.escapeJava("He didn't say, \"stop!\"")); System.out.println(StringEscapeUtils.escapeHtml("bread & butter");); System.out.println(StringEscapeUtils.escapeSql("i don't know")););
The output
He didn't say, \"stop!\" bread & ; butter i don''t know
RandomStringUtils defines operations for random Strings.
E.g.
// RandomStringUtils System.out.println(RandomStringUtils.random(20)); System.out.println(RandomStringUtils.randomAscii(20)); System.out.println(RandomStringUtils.randomAlphabetic(20)); System.out.println(RandomStringUtils.randomAlphanumeric(20)); System.out.println(RandomStringUtils.randomNumeric(20));
The output
..... Blxuk4xp%Zw49p$Y)eg9 lTcRpzniwpLhycEWdfSf fls2ojJiz4bFPrFvMKQP 30411987433704211638
WordUtils defines perations on Strings that contain words.
E.g.
// WordUtils String input = "Wrapped after 5 columns."; System.out.println(WordUtils.wrap(input, 5)); System.out.println(WordUtils.capitalize("I Am Here 123")); System.out.println(WordUtils.capitalizeFully("I AM HERE 123")); char[] chars = new char[]{'-', '+', ' ', '@'}; System.out.println(WordUtils.uncapitalize("i-am+HERE 123", chars)); System.out.println(WordUtils.initials("Ben J.Lee")); System.out.println(WordUtils.swapCase("i am HERE 123"));
The output
Wrapped after 5 columns. I Am Here 123 I Am Here 123 i-am+hERE 123 BJ I AM here 123
Next in the series include
- Character handling – CharSetUtils, CharSet, CharRange, CharUtils
- JVM interaction – SystemUtils, CharEncoding
- Serialization – SerializationUtils, SerializationException
- Assorted functions – ObjectUtils, ClassUtils, ArrayUtils, BooleanUtils
- lang.math, lang.time, lang.text
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