2.6. Stripping and Trimming a String
Problem
You need to strip or trim a string of extraneous whitespace, control characters, or other specified characters.
Solution
StringUtils.trim()
takes a string and removes every whitespace
and control character from the beginning and the end:
String test1 = " \a\r Testing 1 2 3 "; String test2 = " \r\n "; String trimTest1 = StringUtils.trim( test1 ); String trimTest2 = StringUtils.trimToNull( test2 ); System.out.println( trimTest1 ); System.our.println( trimTest2 );
This code produces the following result. The test1
variable is trimmed of leading and trailing whitespace, and the
test2
variable is trimmed to
null
:
Testing 1 2 3 null
Discussion
A control character
is defined as all characters below 32 on the ASCII
table—everything from 0
(NUL)
to 31
(unit
separator)
.
StringUtils.trim( )
delegates to the
trim( )
function on String
and
gracefully handles null
. When you pass a
null
to StringUtils.trim( )
, it
returns a null
.
Stripping a string
If a string contains leading and trailing characters to be removed,
you can remove them with StringUtils.strip( )
. The
strip( )
method differs from trim( )
in that you can specify a set of characters to strip from
the beginning and end of a string. In this example, dashes and
asterisks are stripped from the start and end of a string:
String original = "-------***---SHAZAM!---***-------"; String stripped = StringUtils.strip( original, "-*" ); System.out.println( "Stripped: " + stripped )
This produces the ...
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