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Préférences
Moteurs de recherche
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JavaTM 2 Platform Std. Ed. v1.4.2
java.text
|
Symbol | Location | Localized? | Meaning |
---|---|---|---|
0
| Number | Yes | Digit |
#
| Number | Yes | Digit, zero shows as absent |
.
| Number | Yes | Decimal separator or monetary decimal separator |
-
| Number | Yes | Minus sign |
,
| Number | Yes | Grouping separator |
E
| Number | Yes | Separates mantissa and exponent in scientific notation. Need not be quoted in prefix or suffix. |
;
| Subpattern boundary | Yes | Separates positive and negative subpatterns |
%
| Prefix or suffix | Yes | Multiply by 100 and show as percentage |
\u2030
| Prefix or suffix | Yes | Multiply by 1000 and show as per mille |
¤ (\u00A4 )
| Prefix or suffix | No | Currency sign, replaced by currency symbol. If doubled, replaced by international currency symbol. If present in a pattern, the monetary decimal separator is used instead of the decimal separator. |
'
| Prefix or suffix | No | Used to quote special characters in a prefix or suffix,
for example, "'#'#" formats 123 to
"#123" . To create a single quote
itself, use two in a row: "# o''clock" .
|
Numbers in scientific notation are expressed as the product of a mantissa
and a power of ten, for example, 1234 can be expressed as 1.234 x 10^3. The
mantissa is often in the range 1.0 <= x < 10.0, but it need not be.
DecimalFormat
can be instructed to format and parse scientific
notation only via a pattern; there is currently no factory method
that creates a scientific notation format. In a pattern, the exponent
character immediately followed by one or more digit characters indicates
scientific notation. Example: "0.###E0"
formats the number
1234 as "1.234E3"
.
"0.###E0 m/s"
.
"##0.#####E0"
. Using this pattern, the number 12345
formats to "12.345E3"
, and 123456 formats to
"123.456E3"
.
"00.###E0"
yields
"12.3E-4"
.
"##0.##E0"
is "12.3E3"
. To show all digits, set
the significant digits count to zero. The number of significant digits
does not affect parsing.
DecimalFormat
uses half-even rounding (see
ROUND_HALF_EVEN
) for
formatting.
DecimalFormat
uses the ten consecutive
characters starting with the localized zero digit defined in the
DecimalFormatSymbols
object as digits. For parsing, these
digits as well as all Unicode decimal digits, as defined by
Character.digit
, are recognized.
NaN
is formatted as a single character, typically
\uFFFD
. This character is determined by the
DecimalFormatSymbols
object. This is the only value for which
the prefixes and suffixes are not used.
Infinity is formatted as a single character, typically
\u221E
, with the positive or negative prefixes and suffixes
applied. The infinity character is determined by the
DecimalFormatSymbols
object.
Negative zero ("-0"
) parses to Double(-0.0)
,
unless isParseIntegerOnly()
is true, in which case it parses to
Long(0)
.
Decimal formats are generally not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.
// Print out a number using the localized number, integer, currency, // and percent format for each locale Locale[] locales = NumberFormat.getAvailableLocales(); double myNumber = -1234.56; NumberFormat form; for (int j=0; j<4; ++j) { System.out.println("FORMAT"); for (int i = 0; i < locales.length; ++i) { if (locales[i].getCountry().length() == 0) { continue; // Skip language-only locales } System.out.print(locales[i].getDisplayName()); switch (j) { case 0: form = NumberFormat.getInstance(locales[i]); break; case 1: form = NumberFormat.getIntegerInstance(locales[i]); break; case 2: form = NumberFormat.getCurrencyInstance(locales[i]); break; default: form = NumberFormat.getPercentInstance(locales[i]); break; } if (form instanceof DecimalFormat) { System.out.print(": " + ((DecimalFormat) form).toPattern()); } System.out.print(" -> " + form.format(myNumber)); try { System.out.println(" -> " + form.parse(form.format(myNumber))); } catch (ParseException e) {} } }
Nested Class Summary |
Nested classes inherited from class java.text.NumberFormat |
NumberFormat.Field |
Field Summary |
Fields inherited from class java.text.NumberFormat |
FRACTION_FIELD, INTEGER_FIELD |
Constructor Summary | |
DecimalFormat()
Creates a DecimalFormat using the default pattern and symbols for the default locale. |
|
DecimalFormat(String pattern)
Creates a DecimalFormat using the given pattern and the symbols for the default locale. |
|
DecimalFormat(String pattern,
DecimalFormatSymbols symbols)
Creates a DecimalFormat using the given pattern and symbols. |
Method Summary | |
void |
applyLocalizedPattern(String pattern)
Apply the given pattern to this Format object. |
void |
applyPattern(String pattern)
Apply the given pattern to this Format object. |
Object |
clone()
Standard override; no change in semantics. |
boolean |
equals(Object obj)
Overrides equals |
StringBuffer |
format(double number,
StringBuffer result,
FieldPosition fieldPosition)
Formats a double to produce a string. |
StringBuffer |
format(long number,
StringBuffer result,
FieldPosition fieldPosition)
Format a long to produce a string. |
AttributedCharacterIterator |
formatToCharacterIterator(Object obj)
Formats an Object producing an AttributedCharacterIterator . |
Currency |
getCurrency()
Gets the currency used by this decimal format when formatting currency values. |
DecimalFormatSymbols |
getDecimalFormatSymbols()
Returns the decimal format symbols, which is generally not changed by the programmer or user. |
int |
getGroupingSize()
Return the grouping size. |
int |
getMultiplier()
Get the multiplier for use in percent, permill, etc. |
String |
getNegativePrefix()
Get the negative prefix. |
String |
getNegativeSuffix()
Get the negative suffix. |
String |
getPositivePrefix()
Get the positive prefix. |
String |
getPositiveSuffix()
Get the positive suffix. |
int |
hashCode()
Overrides hashCode |
boolean |
isDecimalSeparatorAlwaysShown()
Allows you to get the behavior of the decimal separator with integers. |
Number |
parse(String text,
ParsePosition pos)
Parses text from a string to produce a Number . |
void |
setCurrency(Currency currency)
Sets the currency used by this number format when formatting currency values. |
void |
setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
Sets the decimal format symbols, which is generally not changed by the programmer or user. |
void |
setDecimalSeparatorAlwaysShown(boolean newValue)
Allows you to set the behavior of the decimal separator with integers. |
void |
setGroupingSize(int newValue)
Set the grouping size. |
void |
setMaximumFractionDigits(int newValue)
Sets the maximum number of digits allowed in the fraction portion of a number. |
void |
setMaximumIntegerDigits(int newValue)
Sets the maximum number of digits allowed in the integer portion of a number. |
void |
setMinimumFractionDigits(int newValue)
Sets the minimum number of digits allowed in the fraction portion of a number. |
void |
setMinimumIntegerDigits(int newValue)
Sets the minimum number of digits allowed in the integer portion of a number. |
void |
setMultiplier(int newValue)
Set the multiplier for use in percent, permill, etc. |
void |
setNegativePrefix(String newValue)
Set the negative prefix. |
void |
setNegativeSuffix(String newValue)
Set the positive suffix. |
void |
setPositivePrefix(String newValue)
Set the positive prefix. |
void |
setPositiveSuffix(String newValue)
Set the positive suffix. |
String |
toLocalizedPattern()
Synthesizes a localized pattern string that represents the current state of this Format object. |
String |
toPattern()
Synthesizes a pattern string that represents the current state of this Format object. |
Methods inherited from class java.text.Format |
format, parseObject |
Methods inherited from class java.lang.Object |
finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public DecimalFormat()
To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getNumberInstance. These factories will return the most appropriate sub-class of NumberFormat for a given locale.
NumberFormat.getInstance()
,
NumberFormat.getNumberInstance()
,
NumberFormat.getCurrencyInstance()
,
NumberFormat.getPercentInstance()
public DecimalFormat(String pattern)
To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getNumberInstance. These factories will return the most appropriate sub-class of NumberFormat for a given locale.
pattern
- A non-localized pattern string.
NullPointerException
- if pattern
is null
IllegalArgumentException
- if the given pattern is invalid.NumberFormat.getInstance()
,
NumberFormat.getNumberInstance()
,
NumberFormat.getCurrencyInstance()
,
NumberFormat.getPercentInstance()
public DecimalFormat(String pattern, DecimalFormatSymbols symbols)
To obtain standard formats for a given locale, use the factory methods on NumberFormat such as getInstance or getCurrencyInstance. If you need only minor adjustments to a standard format, you can modify the format returned by a NumberFormat factory method.
pattern
- a non-localized pattern stringsymbols
- the set of symbols to be used
NullPointerException
- if any of the given arguments is null
IllegalArgumentException
- if the given pattern is invalidNumberFormat.getInstance()
,
NumberFormat.getNumberInstance()
,
NumberFormat.getCurrencyInstance()
,
NumberFormat.getPercentInstance()
,
DecimalFormatSymbols
Method Detail |
public StringBuffer format(double number, StringBuffer result, FieldPosition fieldPosition)
format
in class NumberFormat
number
- The double to formatresult
- where the text is to be appendedfieldPosition
- On input: an alignment field, if desired.
On output: the offsets of the alignment field.
FieldPosition
public StringBuffer format(long number, StringBuffer result, FieldPosition fieldPosition)
format
in class NumberFormat
number
- The long to formatresult
- where the text is to be appendedfieldPosition
- On input: an alignment field, if desired.
On output: the offsets of the alignment field.
FieldPosition
public AttributedCharacterIterator formatToCharacterIterator(Object obj)
AttributedCharacterIterator
.
You can use the returned AttributedCharacterIterator
to build the resulting String, as well as to determine information
about the resulting String.
Each attribute key of the AttributedCharacterIterator will be of type
NumberFormat.Field
, with the attribute value being the
same as the attribute key.
formatToCharacterIterator
in class Format
obj
- The object to format
NullPointerException
- if obj is null.
IllegalArgumentException
- when the Format cannot format the
given object.public Number parse(String text, ParsePosition pos)
Number
.
The method attempts to parse text starting at the index given by
pos
.
If parsing succeeds, then the index of pos
is updated
to the index after the last character used (parsing does not necessarily
use all characters up to the end of the string), and the parsed
number is returned. The updated pos
can be used to
indicate the starting point for the next call to this method.
If an error occurs, then the index of pos
is not
changed, the error index of pos
is set to the index of
the character where the error occurred, and null is returned.
The most economical subclass that can represent the number given by the
string is chosen. Most integer values are returned as Long
objects, no matter how they are written: "17"
and
"17.000"
both parse to Long(17)
. Values that
cannot fit into a Long
are returned as
Double
s. This includes values with a fractional part,
infinite values, NaN
, and the value -0.0.
DecimalFormat
does not decide whether to return
a Double
or a Long
based on the presence of a
decimal separator in the source string. Doing so would prevent integers
that overflow the mantissa of a double, such as
"10,000,000,000,000,000.00"
, from being parsed accurately.
Currently, the only classes that parse
returns are
Long
and Double
, but callers should not rely
on this. Callers may use the Number
methods
doubleValue
, longValue
, etc., to obtain the
type they want.
DecimalFormat
parses all Unicode characters that represent
decimal digits, as defined by Character.digit()
. In
addition, DecimalFormat
also recognizes as digits the ten
consecutive characters starting with the localized zero digit defined in
the DecimalFormatSymbols
object.
parse
in class NumberFormat
text
- the string to be parsedpos
- A ParsePosition
object with index and error
index information as described above.
null
if the parse fails
NullPointerException
- if text
or
pos
is null.NumberFormat.isParseIntegerOnly()
,
Format.parseObject(java.lang.String, java.text.ParsePosition)
public DecimalFormatSymbols getDecimalFormatSymbols()
DecimalFormatSymbols
public void setDecimalFormatSymbols(DecimalFormatSymbols newSymbols)
newSymbols
- desired DecimalFormatSymbolsDecimalFormatSymbols
public String getPositivePrefix()
Examples: +123, $123, sFr123
public void setPositivePrefix(String newValue)
Examples: +123, $123, sFr123
public String getNegativePrefix()
Examples: -123, ($123) (with negative suffix), sFr-123
public void setNegativePrefix(String newValue)
Examples: -123, ($123) (with negative suffix), sFr-123
public String getPositiveSuffix()
Example: 123%
public void setPositiveSuffix(String newValue)
Example: 123%
public String getNegativeSuffix()
Examples: -123%, ($123) (with positive suffixes)
public void setNegativeSuffix(String newValue)
Examples: 123%
public int getMultiplier()
Examples: with 100, 1.23 -> "123", and "123" -> 1.23
public void setMultiplier(int newValue)
Examples: with 100, 1.23 -> "123", and "123" -> 1.23
public int getGroupingSize()
public void setGroupingSize(int newValue)
public boolean isDecimalSeparatorAlwaysShown()
Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
public void setDecimalSeparatorAlwaysShown(boolean newValue)
Example: Decimal ON: 12345 -> 12345.; OFF: 12345 -> 12345
public Object clone()
clone
in class NumberFormat
public boolean equals(Object obj)
equals
in class NumberFormat
public int hashCode()
hashCode
in class NumberFormat
public String toPattern()
applyPattern(java.lang.String)
public String toLocalizedPattern()
applyPattern(java.lang.String)
public void applyPattern(String pattern)
There is no limit to integer digits are set by this routine, since that is the typical end-user desire; use setMaximumInteger if you want to set a real value. For negative numbers, use a second pattern, separated by a semicolon
Example "#,#00.0#"
-> 1,234.56
This means a minimum of 2 integer digits, 1 fraction digit, and a maximum of 2 fraction digits.
Example: "#,#00.0#;(#,#00.0#)"
for negatives in
parentheses.
In negative patterns, the minimum and maximum counts are ignored; these are presumed to be set in the positive pattern.
NullPointerException
- if pattern
is null
IllegalArgumentException
- if the given pattern is invalid.public void applyLocalizedPattern(String pattern)
There is no limit to integer digits are set by this routine, since that is the typical end-user desire; use setMaximumInteger if you want to set a real value. For negative numbers, use a second pattern, separated by a semicolon
Example "#,#00.0#"
-> 1,234.56
This means a minimum of 2 integer digits, 1 fraction digit, and a maximum of 2 fraction digits.
Example: "#,#00.0#;(#,#00.0#)"
for negatives in
parentheses.
In negative patterns, the minimum and maximum counts are ignored; these are presumed to be set in the positive pattern.
NullPointerException
- if pattern
is null
IllegalArgumentException
- if the given pattern is invalid.public void setMaximumIntegerDigits(int newValue)
setMaximumIntegerDigits
in class NumberFormat
newValue
- the maximum number of integer digits to be shown; if
less than zero, then zero is used. The concrete subclass may enforce an
upper limit to this value appropriate to the numeric type being formatted.NumberFormat.setMaximumIntegerDigits(int)
public void setMinimumIntegerDigits(int newValue)
setMinimumIntegerDigits
in class NumberFormat
newValue
- the minimum number of integer digits to be shown; if
less than zero, then zero is used. The concrete subclass may enforce an
upper limit to this value appropriate to the numeric type being formatted.NumberFormat.setMinimumIntegerDigits(int)
public void setMaximumFractionDigits(int newValue)
setMaximumFractionDigits
in class NumberFormat
newValue
- the maximum number of fraction digits to be shown; if
less than zero, then zero is used. The concrete subclass may enforce an
upper limit to this value appropriate to the numeric type being formatted.NumberFormat.setMaximumFractionDigits(int)
public void setMinimumFractionDigits(int newValue)
setMinimumFractionDigits
in class NumberFormat
newValue
- the minimum number of fraction digits to be shown; if
less than zero, then zero is used. The concrete subclass may enforce an
upper limit to this value appropriate to the numeric type being formatted.NumberFormat.setMinimumFractionDigits(int)
public Currency getCurrency()
DecimalFormatSymbols.getCurrency
on this number format's symbols.
getCurrency
in class NumberFormat
null
public void setCurrency(Currency currency)
DecimalFormatSymbols.setCurrency
on this number format's symbols.
setCurrency
in class NumberFormat
currency
- the new currency to be used by this decimal format
NullPointerException
- if currency
is null