StringUtils.replace('abaa', 'A', 'z', 1, false) = 'abaa' StringUtils.replace('abaa', 'a', 'z', 0, false) = 'abaa' StringUtils.replace('abaa', 'a', null, -1, false) = 'abaa' StringUtils.replace('any', *, *, 0, false) = 'any' StringUtils.replace('any', '', *, *, false) = 'any' StringUtils.replace('any', *, null, *, false) = 'any'

StringUtils.replace('any', null, *, *, false) = 'any' StringUtils.replace(null, *, *, *, false) = null Replaces a String with another String inside a larger String,įor the first max values of the search String,Ĭase sensitively/insensitively based on ignoreCase value.Ī null reference passed to this method is a no-op. Parameters: str - the String to get the substring from, may be null start - the position to start from, negative means count back from the end of the String by this many characters end - the position to end at (exclusive), negative means count back from the end of the String by this manyĬharacters Returns: substring from start position to end position, StringUtils.substring('abc', -4, 2) = 'ab' StringUtils.substring('abc', 0, 2) = 'ab' If start is not strictly to the left of end, '' Specify offsets relative to the end of the String. Negative start and end positions can be used to Zero-based - i.e., to start at the beginning of the string use Position and ends before the end position. The returned substring starts with the character in the start Gets a substring from the specified String avoiding exceptions.Ī negative start position can be used to start/end n This class's source was modified from the Apache commons-lang library: NullPointerException should be considered a bug in That is to say that a null input will return null.Ī side effect of the null handling is that a StringUtils handles null input Strings quietly. trim - the characters whitespace - the characters defined by Character.isWhitespace(char).space - the space character ( ' ', char 32).The StringUtils class defines certain words related to the number of changes needed to change one String into another compares Strings and reports on their differences abbreviates a string using ellipsis or another given String IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable.counts the number of occurrences of one String in another UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize.prepends a prefix to the start of the String if not present appends a suffix to the end of the String if not present Searches a String and replaces one String with another splits a String into an array of substrings and vice versa

substring extraction relative to other strings

SubstringBefore/SubstringAfter/SubstringBetween.

does String contains only/none/any of these characters

IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut.

check if a String ends with a suffix null-safe check if a String starts with a prefix null-safe To check if Java String is blank, we use the isBlank() method.- removes leading and trailing whitespace For example, the following string is blank. } Check if Java String is Whitespace or BlankĪ Java String can also be blank or consist of only whitespace characters.

} Check if the string is not null and not emptyĮither way, it is always better to first check if the String is not null. So to check if the string value is empty, you can either use the isEmpty() method or explicitly check the length of a string. If you look at the implementation of the isEmpty() method in Java, you will see that it simply checks if the length of a string is zero. To check if the Java string is empty, you can use the isEmpty() method. The main difference between an empty string and a null string is that an empty string is a string instance of zero length, whereas a null string has no value at all. ('Variable name is not initialized ') Īn empty string in Java is a string of zero length. Either way, if you need to check if the variable is null you do it with a double equal sign(=). You can also assign a null value to a variable explicitly. If a String variable in Java has not been initialized, its value is null. Check if Java String is Null, Empty or Blank Check If Java String is Null.Check if Java String is Whitespace or Blank.Check if the string is not null and not empty.User Registration, Log in, Log out – Video Tutorials.

Java string null or empty