java.lang.Object java.lang.String
public final class String
The String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class.
Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared. For example:
String str = "abc";
is equivalent to:
char data[] = {'a', 'b', 'c'};
String str = new String(data);
Here are some more examples of how strings can be used:
System.out.println("abc");
String cde = "cde";
System.out.println("abc" + cde);
String c = "abc".substring(2,3);
String d = cde.substring(1, 2);
The class String includes methods for examining individual characters of the sequence, for comparing strings, for searching strings, for extracting substrings, and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping is based on the Unicode Standard version specified by the Character class.
The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings. String concatenation is implemented through the StringBuilder(or StringBuffer) class and its append method. String conversions are implemented through the method toString, defined by Object and inherited by all classes in Java. For additional information on string concatenation and conversion, see Gosling, Joy, and Steele, The Java Language Specification.
Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.
A String represents a string in the UTF-16 format in which supplementary characters are represented by surrogate pairs (see the section Unicode Character Representations in the Character class for more information). Index values refer to char code units, so a supplementary character uses two positions in a String.
The String class provides methods for dealing with Unicode code points (i.e., characters), in addition to those for dealing with Unicode code units (i.e., char values).
Object.toString(), StringBuffer, StringBuilder, Charset, Serialized Form
String()
String object so that it represents an empty character sequence. String(byte[] bytes)
String(byte[] ascii, int hibyte)
String constructors that take a charset name or that use the platform's default charset. String(byte[] bytes, int offset, int length)
String(byte[] ascii, int hibyte, int offset, int count)
String constructors that take a charset name or that use the platform's default charset. String(byte[] bytes, int offset, int length, String charsetName)
String(byte[] bytes, String charsetName)
String(char[] value)
String so that it represents the sequence of characters currently contained in the character array argument. String(char[] value, int offset, int count)
String that contains characters from a subarray of the character array argument. String(int[] codePoints, int offset, int count)
String that contains characters from a subarray of the Unicode code point array argument. String(String original)
String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. String(StringBuffer buffer)
String(StringBuilder builder)
char charAt(int index)
char value at the specified index. int codePointAt(int index)
int codePointBefore(int index)
int codePointCount(int beginIndex, int endIndex)
String. int compareTo(String anotherString)
int compareToIgnoreCase(String str)
String concat(String str)
boolean contains(CharSequence s)
boolean contentEquals(CharSequence cs)
boolean contentEquals(StringBuffer sb)
static String copyValueOf(char[] data)
static String copyValueOf(char[] data, int offset, int count)
boolean endsWith(String suffix)
boolean equals(Object anObject)
boolean equalsIgnoreCase(String anotherString)
String to another String, ignoring case considerations. static String format(Locale l, String format, Object... args)
static String format(String format, Object... args)
byte[] getBytes()
void getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin)
getBytes() method, which uses the platform's default charset. byte[] getBytes(String charsetName)
void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
int hashCode()
int indexOf(int ch)
int indexOf(int ch, int fromIndex)
int indexOf(String str)
int indexOf(String str, int fromIndex)
String intern()
int lastIndexOf(int ch)
int lastIndexOf(int ch, int fromIndex)
int lastIndexOf(String str)
int lastIndexOf(String str, int fromIndex)
int length()
boolean matches(String regex)
int offsetByCodePoints(int index, int codePointOffset)
String that is offset from the given index by codePointOffset code points. boolean regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len)
boolean regionMatches(int toffset, String other, int ooffset, int len)
String replace(char oldChar, char newChar)
oldChar in this string with newChar. String replace(CharSequence target, CharSequence replacement)
String replaceAll(String regex, String replacement)
String replaceFirst(String regex, String replacement)
String[] split(String regex)
String[] split(String regex, int limit)
boolean startsWith(String prefix)
boolean startsWith(String prefix, int toffset)
CharSequence subSequence(int beginIndex, int endIndex)
String substring(int beginIndex)
String substring(int beginIndex, int endIndex)
char[] toCharArray()
String toLowerCase()
String to lower case using the rules of the default locale. String toLowerCase(Locale locale)
String to lower case using the rules of the given Locale. String toString()
String toUpperCase()
String to upper case using the rules of the default locale. String toUpperCase(Locale locale)
String to upper case using the rules of the given Locale. String trim()
static String valueOf(boolean b)
boolean argument. static String valueOf(char c)
char argument. static String valueOf(char[] data)
char array argument. static String valueOf(char[] data, int offset, int count)
char array argument. static String valueOf(double d)
double argument. static String valueOf(float f)
float argument. static String valueOf(int i)
int argument. static String valueOf(long l)
long argument. static String valueOf(Object obj)
Object argument. CASE_INSENSITIVE_ORDER
public static final Comparator<String> CASE_INSENSITIVE_ORDER
String objects as by compareToIgnoreCase. This comparator is serializable.
Note that this Comparator does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides Collators to allow locale-sensitive ordering.
Collator.compare(String, String)
public String()
String object so that it represents an empty character sequence. Note that use of this constructor is unnecessary since Strings are immutable.
public String(String original)
String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of original is needed, use of this constructor is unnecessary since Strings are immutable.
original - a String.
public String(char[] value)
String so that it represents the sequence of characters currently contained in the character array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.
value - the initial value of the string.
public String(char[] value,
int offset,
int count)
String that contains characters from a subarray of the character array argument. The offset argument is the index of the first character of the subarray and the count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.
value - array that is the source of characters.
offset - the initial offset.
count - the length.
IndexOutOfBoundsException - if the offset and count arguments index characters outside the bounds of the value array.
public String(int[] codePoints,
int offset,
int count)
String that contains characters from a subarray of the Unicode code point array argument. The offset argument is the index of the first code point of the subarray and the count argument specifies the length of the subarray. The contents of the subarray are converted to chars; subsequent modification of the int array does not affect the newly created string.
codePoints - array that is the source of Unicode code points.
offset - the initial offset.
count - the length.
IllegalArgumentException - if any invalid Unicode code point is found in codePoints
IndexOutOfBoundsException - if the offset and count arguments index characters outside the bounds of the codePoints array.
@Deprecated
public String(byte[] ascii,
int hibyte,
int offset,
int count)
String constructors that take a charset name or that use the platform's default charset.
String constructed from a subarray of an array of 8-bit integer values.
The offset argument is the index of the first byte of the subarray, and the count argument specifies the length of the subarray.
Each byte in the subarray is converted to a char as specified in the method above.
ascii - the bytes to be converted to characters.
hibyte - the top 8 bits of each 16-bit Unicode character.
offset - the initial offset.
count - the length.
IndexOutOfBoundsException - if the offset or count argument is invalid.
String(byte[], int), String(byte[], int, int, java.lang.String), String(byte[], int, int), String(byte[], java.lang.String), String(byte[])
@Deprecated
public String(byte[] ascii,
int hibyte)
String constructors that take a charset name or that use the platform's default charset.
String containing characters constructed from an array of 8-bit integer values. Each character cin the resulting string is constructed from the corresponding component b in the byte array such that:
c == (char)(((hibyte & 0xff) << 8)
| (b & 0xff))
ascii - the bytes to be converted to characters.
hibyte - the top 8 bits of each 16-bit Unicode character.
String(byte[], int, int, java.lang.String), String(byte[], int, int), String(byte[], java.lang.String), String(byte[])
public String(byte[] bytes,
int offset,
int length,
String charsetName)
throws UnsupportedEncodingException
The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.
bytes - the bytes to be decoded into characters
offset - the index of the first byte to decode
length - the number of bytes to decode
charsetName - the name of a supported UnsupportedEncodingException - if the named charset is not supported
IndexOutOfBoundsException - if the offset and length arguments index characters outside the bounds of the bytes array
public String(byte[] bytes,
String charsetName)
throws UnsupportedEncodingException
The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.
bytes - the bytes to be decoded into characters
charsetName - the name of a supported UnsupportedEncodingException - If the named charset is not supported
public String(byte[] bytes,
int offset,
int length)
The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.
bytes - the bytes to be decoded into characters
offset - the index of the first byte to decode
length - the number of bytes to decode
IndexOutOfBoundsException - if the offset and the length arguments index characters outside the bounds of the bytes array
public String(byte[] bytes)
The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The CharsetDecoder class should be used when more control over the decoding process is required.
bytes - the bytes to be decoded into characters
public String(StringBuffer buffer)
buffer - a StringBuffer.
public String(StringBuilder builder)
This constructor is provided to ease migration to StringBuilder. Obtaining a string from a string builder via the toString method is likely to run faster and is generally preferred.
builder - a StringBuilder
public int length()
length in interface CharSequence
public char charAt(int index)
char value at the specified index. An index ranges from 0 to length() - 1. The first char value of the sequence is at index 0, the next at index 1, and so on, as for array indexing.
If the char value specified by the index is a surrogate, the surrogate value is returned.
charAt in interface CharSequence
index - the index of the char value.
char value at the specified index of this string. The first char value is at index 0.
IndexOutOfBoundsException - if the index argument is negative or not less than the length of this string.
public int codePointAt(int index)
char values (Unicode code units) and ranges from 0 to length() - 1.
If the char value specified at the given index is in the high-surrogate range, the following index is less than the length of this String, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.
index - the index to the char values
index
IndexOutOfBoundsException - if the index argument is negative or not less than the length of this string.
public int codePointBefore(int index)
char values (Unicode code units) and ranges from 1 to length.
If the char value at (index - 1) is in the low-surrogate range, (index - 2) is not negative, and the char value at (index - 2) is in the high-surrogate range, then the supplementary code point value of the surrogate pair is returned. If the char value at index - 1 is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned.
index - the index following the code point that should be returned
IndexOutOfBoundsException - if the index argument is less than 1 or greater than the length of this string.
public int codePointCount(int beginIndex,
int endIndex)
String. The text range begins at the specified beginIndex and extends to the char at index endIndex - 1. Thus the length (in chars) of the text range is endIndex-beginIndex. Unpaired surrogates within the text range count as one code point each.
beginIndex - the index to the first char of the text range.
endIndex - the index after the last char of the text range.
IndexOutOfBoundsException - if the beginIndex is negative, or endIndex is larger than the length of this String, or beginIndex is larger than endIndex.
public int offsetByCodePoints(int index,
int codePointOffset)
String that is offset from the given index by codePointOffset code points. Unpaired surrogates within the text range given by index and codePointOffset count as one code point each.
index - the index to be offset
codePointOffset - the offset in code points
String
IndexOutOfBoundsException - if index is negative or larger then the length of this String, or if codePointOffset is positive and the substring starting with index has fewer than codePointOffset code points, or if codePointOffset is negative and the substring before index has fewer than the absolute value of codePointOffset code points.
public void getChars(int srcBegin,
int srcEnd,
char[] dst,
int dstBegin)
The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1 (thus the total number of characters to be copied is srcEnd-srcBegin). The characters are copied into the subarray of dst starting at index dstBegin and ending at index:
dstbegin + (srcEnd-srcBegin) - 1
srcBegin - index of the first character in the string to copy.
srcEnd - index after the last character in the string to copy.
dst - the destination array.
dstBegin - the start offset in the destination array.
IndexOutOfBoundsException - If any of the following is true:
srcBegin is negative.srcBegin is greater than srcEndsrcEnd is greater than the length of this stringdstBegin is negativedstBegin+(srcEnd-srcBegin) is larger than dst.length@Deprecated
public void getBytes(int srcBegin,
int srcEnd,
byte[] dst,
int dstBegin)
getBytes() method, which uses the platform's default charset.
The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1. The total number of characters to be copied is srcEnd-srcBegin. The characters, converted to bytes, are copied into the subarray of dst starting at index dstBegin and ending at index:
dstbegin + (srcEnd-srcBegin) - 1
srcBegin - index of the first character in the string to copy.
srcEnd - index after the last character in the string to copy.
dst - the destination array.
dstBegin - the start offset in the destination array.
IndexOutOfBoundsException - if any of the following is true:
srcBegin is negativesrcBegin is greater than srcEndsrcEnd is greater than the length of this StringdstBegin is negativedstBegin+(srcEnd-srcBegin) is larger than dst.lengthpublic byte[] getBytes(String charsetName)
throws UnsupportedEncodingException
The behavior of this method when this string cannot be encoded in the given charset is unspecified. The CharsetEncoder class should be used when more control over the encoding process is required.
charsetName - the name of a supported UnsupportedEncodingException - If the named charset is not supported
public byte[] getBytes()
The behavior of this method when this string cannot be encoded in the default charset is unspecified. The CharsetEncoder class should be used when more control over the encoding process is required.
public boolean equals(Object anObject)
true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.
equals in class Object
anObject - the object to compare this String against.
true if the String are equal; false otherwise.
compareTo(java.lang.String), equalsIgnoreCase(java.lang.String)
public boolean contentEquals(StringBuffer sb)
sb - the StringBuffer to compare to.
NullPointerException - if sb is null
public boolean contentEquals(CharSequence cs)
cs - the sequence to compare to.
NullPointerException - if cs is null
public boolean equalsIgnoreCase(String anotherString)
String to another String, ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length, and corresponding characters in the two strings are equal ignoring case.
Two characters c1 and c2 are considered the same, ignoring case if at least one of the following is true:
== operator).Character.toUpperCase(char) to each character produces the same result.Character.toLowerCase(char) to each character produces the same result.anotherString - the String to compare this String against.
true if the argument is not null and the Strings are equal, ignoring case; false otherwise.
equals(Object), Character.toLowerCase(char), Character.toUpperCase(char)
public int compareTo(String anotherString)
String object is compared lexicographically to the character sequence represented by the argument string. The result is a negative integer if this String object lexicographically precedes the argument string. The result is a positive integer if this String object lexicographically follows the argument string. The result is zero if the strings are equal; compareTo returns 0 exactly when the equals(Object) method would return true.
This is the definition of lexicographic ordering. If two strings are different, then either they have different characters at some index that is a valid index for both strings, or their lengths are different, or both. If they have different characters at one or more index positions, let k be the smallest such index; then the string whose character at position k has the smaller value, as determined by using the < operator, lexicographically precedes the other string. In this case, compareTo returns the difference of the two character values at position k in the two string -- that is, the value:
If there is no index position at which they differ, then the shorter string lexicographically precedes the longer string. In this case,this.charAt(k)-anotherString.charAt(k)
compareTo returns the difference of the lengths of the strings -- that is, the value:
this.length()-anotherString.length()
compareTo in interface Comparable<String>
anotherString - the String to be compared.
0 if the argument string is equal to this string; a value less than 0 if this string is lexicographically less than the string argument; and a value greater than 0 if this string is lexicographically greater than the string argument.
public int compareToIgnoreCase(String str)
compareTo with normalized versions of the strings where case differences have been eliminated by calling Character.toLowerCase(Character.toUpperCase(character)) on each character.
Note that this method does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides collators to allow locale-sensitive ordering.
str - the String to be compared.
Collator.compare(String, String)
public boolean regionMatches(int toffset,
String other,
int ooffset,
int len)
A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent identical character sequences. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is false if and only if at least one of the following is true:
toffset - the starting offset of the subregion in this string.
other - the string argument.
ooffset - the starting offset of the subregion in the string argument.
len - the number of characters to compare.
true if the specified subregion of this string exactly matches the specified subregion of the string argument; false otherwise.
public boolean regionMatches(boolean ignoreCase,
int toffset,
String other,
int ooffset,
int len)
A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent character sequences that are the same, ignoring case if and only if ignoreCase is true. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is false if and only if at least one of the following is true:
this.charAt(toffset+k) != other.charAt(ooffset+k)
Character.toLowerCase(this.charAt(toffset+k)) !=
Character.toLowerCase(other.charAt(ooffset+k))
and:
Character.toUpperCase(this.charAt(toffset+k)) !=
Character.toUpperCase(other.charAt(ooffset+k))
ignoreCase - if true, ignore case when comparing characters.
toffset - the starting offset of the subregion in this string.
other - the string argument.
ooffset - the starting offset of the subregion in the string argument.
len - the number of characters to compare.
true if the specified subregion of this string matches the specified subregion of the string argument; false otherwise. Whether the matching is exact or case insensitive depends on the ignoreCase argument.
public boolean startsWith(String prefix,
int toffset)
prefix - the prefix.
toffset - where to begin looking in the string.
true if the character sequence represented by the argument is a prefix of the substring of this object starting at index toffset; false otherwise. The result is false if toffset is negative or greater than the length of this String object; otherwise the result is the same as the result of the expression
this.substring(toffset).startsWith(prefix)
public boolean startsWith(String prefix)
prefix - the prefix.
true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise. Note also that true will be returned if the argument is an empty string or is equal to this String object as determined by the equals(Object) method.
public boolean endsWith(String suffix)
suffix - the suffix.
true if the character sequence represented by the argument is a suffix of the character sequence represented by this object; false otherwise. Note that the result will be true if the argument is the empty string or is equal to this String object as determined by the equals(Object) method.
public int hashCode()
String object is computed as
usings[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
int arithmetic, where s[i] is the ith character of the string, n is the length of the string, and ^ indicates exponentiation. (The hash value of the empty string is zero.)
hashCode in class Object
Object.equals(java.lang.Object), Hashtable
public int indexOf(int ch)
ch occurs in the character sequence represented by this String object, then the index (in Unicode code units) of the first such occurrence is returned. For values of ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:
is true. For other values ofthis.charAt(k) == ch
ch, it is the smallest value k such that:
is true. In either case, if no such character occurs in this string, thenthis.codePointAt(k) == ch
-1 is returned.
ch - a character (Unicode code point).
-1 if the character does not occur.
public int indexOf(int ch,
int fromIndex)
If a character with value ch occurs in the character sequence represented by this String object at an index no smaller than fromIndex, then the index of the first such occurrence is returned. For values of ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:
is true. For other values of(this.charAt(k) == ch) && (k >= fromIndex)
ch, it is the smallest value k such that:
is true. In either case, if no such character occurs in this string at or after position(this.codePointAt(k) == ch) && (k >= fromIndex)
fromIndex, then -1 is returned.
There is no restriction on the value of fromIndex. If it is negative, it has the same effect as if it were zero: this entire string may be searched. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1 is returned.
All indices are specified in char values (Unicode code units).
ch - a character (Unicode code point).
fromIndex - the index to start the search from.
fromIndex, or -1 if the character does not occur.
public int lastIndexOf(int ch)
ch in the range from 0 to 0xFFFF (inclusive), the index (in Unicode code units) returned is the largest value k such that:
is true. For other values ofthis.charAt(k) == ch
ch, it is the largest value k such that:
is true. In either case, if no such character occurs in this string, thenthis.codePointAt(k) == ch
-1 is returned. The String is searched backwards starting at the last character.
ch - a character (Unicode code point).
-1 if the character does not occur.
public int lastIndexOf(int ch,
int fromIndex)
ch in the range from 0 to 0xFFFF (inclusive), the index returned is the largest value k such that:
is true. For other values of(this.charAt(k) == ch) && (k <= fromIndex)
ch, it is the largest value k such that:
is true. In either case, if no such character occurs in this string at or before position(this.codePointAt(k) == ch) && (k <= fromIndex)
fromIndex, then -1 is returned.
All indices are specified in char values (Unicode code units).
ch - a character (Unicode code point).
fromIndex - the index to start the search from. There is no restriction on the value of fromIndex. If it is greater than or equal to the length of this string, it has the same effect as if it were equal to one less than the length of this string: this entire string may be searched. If it is negative, it has the same effect as if it were -1: -1 is returned.
fromIndex, or -1 if the character does not occur before that point.
public int indexOf(String str)
isthis.startsWith(str, k)
true.
str - any string.
-1 is returned.
public int indexOf(String str,
int fromIndex)
If no such value of k exists, then -1 is returned.k >= Math.min(fromIndex, str.length()) && this.startsWith(str, k)
str - the substring for which to search.
fromIndex - the index from which to start the search.
public int lastIndexOf(String str)
this.length(). The returned index is the largest value k such that
is true.this.startsWith(str, k)
str - the substring to search for.
-1 is returned.
public int lastIndexOf(String str,
int fromIndex)
If no such value of k exists, then -1 is returned.k <= Math.min(fromIndex, str.length()) && this.startsWith(str, k)
str - the substring to search for.
fromIndex - the index to start the search from.
public String substring(int beginIndex)
Examples:
"unhappy".substring(2) returns "happy" "Harbison".substring(3) returns "bison" "emptiness".substring(9) returns "" (an empty string)
beginIndex - the beginning index, inclusive.
IndexOutOfBoundsException - if beginIndex is negative or larger than the length of this String object.
public String substring(int beginIndex,
int endIndex)
beginIndex and extends to the character at index endIndex - 1. Thus the length of the substring is endIndex-beginIndex.
Examples:
"hamburger".substring(4, 8) returns "urge" "smiles".substring(1, 5) returns "mile"
beginIndex - the beginning index, inclusive.
endIndex - the ending index, exclusive.
IndexOutOfBoundsException - if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex.
public CharSequence subSequence(int beginIndex,
int endIndex)
An invocation of this method of the form
behaves in exactly the same way as the invocationstr.subSequence(begin, end)
This method is defined so that the String class can implement thestr.substring(begin, end)
CharSequence interface.
subSequence in interface CharSequence
beginIndex - the begin index, inclusive.
endIndex - the end index, exclusive.
IndexOutOfBoundsException - if beginIndex or endIndex are negative, if endIndex is greater than length(), or if beginIndex is greater than startIndex
public String concat(String str)
If the length of the argument string is 0, then this String object is returned. Otherwise, a new String object is created, representing a character sequence that is the concatenation of the character sequence represented by this String object and the character sequence represented by the argument string.
Examples:
"cares".concat("s") returns "caress"
"to".concat("get").concat("her") returns "together"
str - the String that is concatenated to the end of this String.
public String replace(char oldChar,
char newChar)
oldChar in this string with newChar.
If the character oldChar does not occur in the character sequence represented by this String object, then a reference to this String object is returned. Otherwise, a new String object is created that represents a character sequence identical to the character sequence represented by this String object, except that every occurrence of oldChar is replaced by an occurrence of newChar.
Examples:
"mesquite in your cellar".replace('e', 'o')
returns "mosquito in your collar"
"the war of baronets".replace('r', 'y')
returns "the way of bayonets"
"sparring with a purple porpoise".replace('p', 't')
returns "starring with a turtle tortoise"
"JonL".replace('q', 'x') returns "JonL" (no change)
oldChar - the old character.
newChar - the new character.
oldChar with newChar.
public boolean matches(String regex)
An invocation of this method of the form str.matches(regex) yields exactly the same result as the expression
Pattern.matches(regex, str)
regex - the regular expression to which this string is to be matched
PatternSyntaxException - if the regular expression's syntax is invalid
Pattern
public boolean contains(CharSequence s)
s - the sequence to search for
s, false otherwise
NullPointerException - if s is null
public String replaceFirst(String regex,
String replacement)
An invocation of this method of the form str.replaceFirst(regex, repl) yields exactly the same result as the expression
Pattern.compile(regex).matcher(str).replaceFirst(repl)
regex - the regular expression to which this string is to be matched
PatternSyntaxException - if the regular expression's syntax is invalid
Pattern
public String replaceAll(String regex,
String replacement)
An invocation of this method of the form str.replaceAll(regex, repl) yields exactly the same result as the expression
Pattern.compile(regex).matcher(str).replaceAll(repl)
regex - the regular expression to which this string is to be matched
PatternSyntaxException - if the regular expression's syntax is invalid
Pattern
public String replace(CharSequence target,
CharSequence replacement)
target - The sequence of char values to be replaced
replacement - The replacement sequence of char values
NullPointerException - if target or replacement is null.
public String[] split(String regex,
int limit)
The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.
The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.
The string "boo:and:foo", for example, yields the following results with these parameters:
Regex Limit Result : 2 { "boo", "and:foo" } : 5 { "boo", "and", "foo" } : -2 { "boo", "and", "foo" } o 5 { "b", "", ":and:f", "", "" } o -2 { "b", "", ":and:f", "", "" } o 0 { "b", "", ":and:f" }
An invocation of this method of the form str.split(regex, n) yields the same result as the expression
Pattern.compile(regex).split(str, n)
regex - the delimiting regular expression
limit - the result threshold, as described above
PatternSyntaxException - if the regular expression's syntax is invalid
Pattern
public String[] split(String regex)
This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.
The string "boo:and:foo", for example, yields the following results with these expressions:
Regex Result : { "boo", "and", "foo" } o { "b", "", ":and:f" }
regex - the delimiting regular expression
PatternSyntaxException - if the regular expression's syntax is invalid
Pattern
public String toLowerCase(Locale locale)
String to lower case using the rules of the given Locale. Case mapping is based on the Unicode Standard version specified by the Character class. Since case mappings are not always 1:1 char mappings, the resulting String may be a different length than the original String.
Examples of lowercase mappings are in the following table:
locale - use the case transformation rules for this locale
String, converted to lowercase.
toLowerCase(), toUpperCase(), toUpperCase(Locale)
public String toLowerCase()
String to lower case using the rules of the default locale. This is equivalent to calling toLowerCase(Locale.getDefault()).
String, converted to lowercase.
toLowerCase(Locale)
public String toUpperCase(Locale locale)
String to upper case using the rules of the given Locale. Case mapping is based on the Unicode Standard version specified by the Character class. Since case mappings are not always 1:1 char mappings, the resulting String may be a different length than the original String.
Examples of locale-sensitive and 1:M case mappings are in the following table.
Language Code of Locale Lower Case Upper Case Description tr (Turkish) \u0069 \u0130 small letter i -> capital letter I with dot above tr (Turkish) \u0131 \u0049 small letter dotless i -> capital letter I (all) \u00df \u0053 \u0053 small letter sharp s -> two letters: SS (all) Fahrvergnügen FAHRVERGNÜGENlocale - use the case transformation rules for this locale
String, converted to uppercase.
toUpperCase(), toLowerCase(), toLowerCase(Locale)
public String toUpperCase()
String to upper case using the rules of the default locale. This method is equivalent to toUpperCase(Locale.getDefault()).
String, converted to uppercase.
toUpperCase(Locale)
public String trim()
If this String object represents an empty character sequence, or the first and last characters of character sequence represented by this String object both have codes greater than '\u0020' (the space character), then a reference to this String object is returned.
Otherwise, if there is no character with a code greater than '\u0020' in the string, then a new String object representing an empty string is created and returned.
Otherwise, let k be the index of the first character in the string whose code is greater than '\u0020', and let m be the index of the last character in the string whose code is greater than '\u0020'. A new String object is created, representing the substring of this string that begins with the character at index k and ends with the character at index m-that is, the result of this.substring(k, m+1).
This method may be used to trim whitespace (as defined above) from the beginning and end of a string.
public String toString()
toString in interface CharSequence
toString in class Object
public char[] toCharArray()
public static String format(String format,
Object... args)
The locale always used is the one returned by Locale.getDefault().
format - A format string
args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
NullPointerException - If the format is null
Formatter
public static String format(Locale l,
String format,
Object... args)
l - The locale to apply during formatting. If l is null then no localization is applied.
format - A format string
args - Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
IllegalFormatException - If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification
NullPointerException - If the format is null
Formatter
public static String valueOf(Object obj)
Object argument.
obj - an Object.
null, then a string equal to "null"; otherwise, the value of obj.toString() is returned.
Object.toString()
public static String valueOf(char[] data)
char array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.
data - a char array.
public static String valueOf(char[] data,
int offset,
int count)
char array argument.
The offset argument is the index of the first character of the subarray. The count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.
data - the character array.
offset - the initial offset into the value of the String.
count - the length of the value of the String.
IndexOutOfBoundsException - if offset is negative, or count is negative, or offset+count is larger than data.length.
public static String copyValueOf(char[] data,
int offset,
int count)
data - the character array.
offset - initial offset of the subarray.
count - length of the subarray.
String that contains the characters of the specified subarray of the character array.
public static String copyValueOf(char[] data)
data - the character array.
String that contains the characters of the character array.
public static String valueOf(boolean b)
boolean argument.
b - a boolean.
true, a string equal to "true" is returned; otherwise, a string equal to "false" is returned.
public static String valueOf(char c)
char argument.
c - a char.
1 containing as its single character the argument c.
public static String valueOf(int i)
int argument.
The representation is exactly the one returned by the Integer.toString method of one argument.
i - an int.
int argument.
Integer.toString(int, int)
public static String valueOf(long l)
long argument.
The representation is exactly the one returned by the Long.toString method of one argument.
l - a long.
long argument.
Long.toString(long)
public static String valueOf(float f)
float argument.
The representation is exactly the one returned by the Float.toString method of one argument.
f - a float.
float argument.
Float.toString(float)
public static String valueOf(double d)
double argument.
The representation is exactly the one returned by the Double.toString method of one argument.
d - a double.
double argument.
Double.toString(double)
public String intern()
A pool of strings, initially empty, is maintained privately by the class String.
When the intern method is invoked, if the pool already contains a string equal to this String object as determined by the equals(Object) method, then the string from the pool is returned. Otherwise, this String object is added to the pool and a reference to this String object is returned.
It follows that for any two strings s and t, s.intern() == t.intern() is true if and only if s.equals(t) is true.
All literal strings and string-valued constant expressions are interned. String literals are defined in §3.10.5 of the Java Language Specification
Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
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