public final class Strings
extends java.lang.Object
Modifier and Type | Field and Description |
---|---|
static java.lang.String |
EMPTY
The empty string.
|
static java.lang.String |
LINE_SEPARATOR
OS-dependent line separator, defaults to
"\n" if the system property ""line.separator" cannot be
read. |
Modifier | Constructor and Description |
---|---|
private |
Strings() |
Modifier and Type | Method and Description |
---|---|
static java.lang.String |
dquote(java.lang.String str)
Returns a double quoted string.
|
static boolean |
isBlank(java.lang.String s)
Checks if a String is blank.
|
static boolean |
isEmpty(java.lang.CharSequence cs)
Checks if a CharSequence is empty ("") or null.
|
static boolean |
isNotBlank(java.lang.String s)
Checks if a String is not blank.
|
static boolean |
isNotEmpty(java.lang.CharSequence cs)
Checks if a CharSequence is not empty ("") and not null.
|
static java.lang.String |
join(java.lang.Iterable<?> iterable,
char separator)
Joins the elements of the provided
Iterable into
a single String containing the provided elements. |
static java.lang.String |
join(java.util.Iterator<?> iterator,
char separator)
Joins the elements of the provided
Iterator into
a single String containing the provided elements. |
static java.lang.String |
left(java.lang.String str,
int len)
Gets the leftmost
len characters of a String. |
static java.lang.String |
quote(java.lang.String str)
Returns a quoted string.
|
static java.lang.String |
toRootUpperCase(java.lang.String str)
Shorthand for
str.toUpperCase(Locale.ROOT); |
static java.lang.String |
trimToNull(java.lang.String str)
Removes control characters (char <= 32) from both ends of this String returning
null if the String is
empty ("") after the trim or if it is null . |
public static final java.lang.String EMPTY
public static final java.lang.String LINE_SEPARATOR
"\n"
if the system property ""line.separator"
cannot be
read.public static java.lang.String dquote(java.lang.String str)
str
- a String"str"
public static boolean isBlank(java.lang.String s)
null
, empty, or when trimmed using
String.trim()
is empty.s
- the String to check, may be null
true
if the String is null
, empty, or trims to empty.public static boolean isEmpty(java.lang.CharSequence cs)
Checks if a CharSequence is empty ("") or null.
Strings.isEmpty(null) = true Strings.isEmpty("") = true Strings.isEmpty(" ") = false Strings.isEmpty("bob") = false Strings.isEmpty(" bob ") = false
NOTE: This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is available in isBlank().
Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isEmpty(CharSequence)
cs
- the CharSequence to check, may be nulltrue
if the CharSequence is empty or nullpublic static boolean isNotBlank(java.lang.String s)
isBlank(String)
.s
- the String to check, may be null
true
if the String is non-null
and has content after being trimmed.public static boolean isNotEmpty(java.lang.CharSequence cs)
Checks if a CharSequence is not empty ("") and not null.
Strings.isNotEmpty(null) = false Strings.isNotEmpty("") = false Strings.isNotEmpty(" ") = true Strings.isNotEmpty("bob") = true Strings.isNotEmpty(" bob ") = true
Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.isNotEmpty(CharSequence)
cs
- the CharSequence to check, may be nulltrue
if the CharSequence is not empty and not nullpublic static java.lang.String join(java.lang.Iterable<?> iterable, char separator)
Joins the elements of the provided Iterable
into
a single String containing the provided elements.
No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.
iterable
- the Iterable
providing the values to join together, may be nullseparator
- the separator character to usenull
if null iterator inputpublic static java.lang.String join(java.util.Iterator<?> iterator, char separator)
Joins the elements of the provided Iterator
into
a single String containing the provided elements.
No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.
iterator
- the Iterator
of values to join together, may be nullseparator
- the separator character to usenull
if null iterator inputpublic static java.lang.String left(java.lang.String str, int len)
Gets the leftmost len
characters of a String.
If len
characters are not available, or the
String is null
, the String will be returned without
an exception. An empty String is returned if len is negative.
StringUtils.left(null, *) = null StringUtils.left(*, -ve) = "" StringUtils.left("", *) = "" StringUtils.left("abc", 0) = "" StringUtils.left("abc", 2) = "ab" StringUtils.left("abc", 4) = "abc"
Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.
str
- the String to get the leftmost characters from, may be nulllen
- the length of the required Stringnull
if null String inputpublic static java.lang.String quote(java.lang.String str)
str
- a String'str'
public static java.lang.String trimToNull(java.lang.String str)
Removes control characters (char <= 32) from both ends of this String returning null
if the String is
empty ("") after the trim or if it is null
.
The String is trimmed using String.trim()
. Trim removes start and end characters <= 32.
Strings.trimToNull(null) = null Strings.trimToNull("") = null Strings.trimToNull(" ") = null Strings.trimToNull("abc") = "abc" Strings.trimToNull(" abc ") = "abc"
Copied from Apache Commons Lang org.apache.commons.lang3.StringUtils.trimToNull(String)
str
- the String to be trimmed, may be nullnull
if only chars <= 32, empty or null String inputpublic static java.lang.String toRootUpperCase(java.lang.String str)
str.toUpperCase(Locale.ROOT);
str
- The string to upper case.String.toLowerCase(Locale)