public abstract class NumberFormat extends Format
NumberFormat is the abstract base class for all number
 formats. This class provides the interface for formatting and parsing
 numbers. NumberFormat also provides methods for determining
 which locales have number formats, and what their names are.
 
 NumberFormat helps you to format and parse numbers for any locale.
 Your code can be completely independent of the locale conventions for
 decimal points, thousands-separators, or even the particular decimal
 digits used, or whether the number format is even decimal.
 
To format a number for the current Locale, use one of the factory class methods:
If you are formatting multiple numbers, it is more efficient to get the format and use it multiple times so that the system doesn't have to fetch the information about the local language and country conventions multiple times.myString = NumberFormat.getInstance().format(myNumber);
To format a number for a different Locale, specify it in the call toNumberFormat nf = NumberFormat.getInstance(); for (int i = 0; i < myNumber.length; ++i) { output.println(nf.format(myNumber[i]) + "; "); }
getInstance.
 You can also use aNumberFormat nf = NumberFormat.getInstance(Locale.FRENCH);
NumberFormat to parse numbers:
 UsemyNumber = nf.parse(myString);
getInstance or getNumberInstance to get the
 normal number format. Use getIntegerInstance to get an
 integer number format. Use getCurrencyInstance to get the
 currency number format. And use getPercentInstance to get a
 format for displaying percentages. With this format, a fraction like
 0.53 is displayed as 53%.
 
 You can also control the display of numbers with such methods as
 setMinimumFractionDigits.
 If you want even more control over the format or parsing,
 or want to give your users more control,
 you can try casting the NumberFormat you get from the factory methods
 to a DecimalFormat. This will work for the vast majority
 of locales; just remember to put it in a try block in case you
 encounter an unusual one.
 
NumberFormat and DecimalFormat are designed such that some controls work for formatting and others work for parsing. The following is the detailed description for each these control methods,
setParseIntegerOnly : only affects parsing, e.g. if true, "3456.78" → 3456 (and leaves the parse position just after index 6) if false, "3456.78" → 3456.78 (and leaves the parse position just after index 8) This is independent of formatting. If you want to not show a decimal point where there might be no digits after the decimal point, use setDecimalSeparatorAlwaysShown.
setDecimalSeparatorAlwaysShown : only affects formatting, and only where there might be no digits after the decimal point, such as with a pattern like "#,##0.##", e.g., if true, 3456.00 → "3,456." if false, 3456.00 → "3456" This is independent of parsing. If you want parsing to stop at the decimal point, use setParseIntegerOnly.
 You can also use forms of the parse and format
 methods with ParsePosition and FieldPosition to
 allow you to:
 
FieldPosition in your format call, with
      field = INTEGER_FIELD. On output,
      getEndIndex will be set to the offset between the
      last character of the integer and the decimal. Add
      (desiredSpaceCount - getEndIndex) spaces at the front of the string.
 getEndIndex.
      Then move the pen by
      (desiredPixelWidth - widthToAlignmentPoint) before drawing the text.
      It also works where there is no decimal, but possibly additional
      characters at the end, e.g., with parentheses in negative
      numbers: "(12)" for -12.
 Number 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.
DecimalFormat, 
ChoiceFormat, 
Serialized Form| Modifier and Type | Class and Description | 
|---|---|
| static class  | NumberFormat.FieldDefines constants that are used as attribute keys in the
  AttributedCharacterIteratorreturned
 fromNumberFormat.formatToCharacterIteratorand as
 field identifiers inFieldPosition. | 
| Modifier and Type | Field and Description | 
|---|---|
| static int | FRACTION_FIELDField constant used to construct a FieldPosition object. | 
| static int | INTEGER_FIELDField constant used to construct a FieldPosition object. | 
| Modifier | Constructor and Description | 
|---|---|
| protected  | NumberFormat()Sole constructor. | 
| Modifier and Type | Method and Description | 
|---|---|
| Object | clone()Overrides Cloneable. | 
| boolean | equals(Object obj)Overrides equals. | 
| String | format(double number)Specialization of format. | 
| abstract StringBuffer | format(double number,
      StringBuffer toAppendTo,
      FieldPosition pos)Specialization of format. | 
| String | format(long number)Specialization of format. | 
| abstract StringBuffer | format(long number,
      StringBuffer toAppendTo,
      FieldPosition pos)Specialization of format. | 
| StringBuffer | format(Object number,
      StringBuffer toAppendTo,
      FieldPosition pos)Formats a number and appends the resulting text to the given string
 buffer. | 
| static Locale[] | getAvailableLocales()Returns an array of all locales for which the
  get*Instancemethods of this class can return
 localized instances. | 
| Currency | getCurrency()Gets the currency used by this number format when formatting
 currency values. | 
| static NumberFormat | getCurrencyInstance()Returns a currency format for the current default
  FORMATlocale. | 
| static NumberFormat | getCurrencyInstance(Locale inLocale)Returns a currency format for the specified locale. | 
| static NumberFormat | getInstance()Returns a general-purpose number format for the current default
  FORMATlocale. | 
| static NumberFormat | getInstance(Locale inLocale)Returns a general-purpose number format for the specified locale. | 
| static NumberFormat | getIntegerInstance()Returns an integer number format for the current default
  FORMATlocale. | 
| static NumberFormat | getIntegerInstance(Locale inLocale)Returns an integer number format for the specified locale. | 
| int | getMaximumFractionDigits()Returns the maximum number of digits allowed in the fraction portion of a
 number. | 
| int | getMaximumIntegerDigits()Returns the maximum number of digits allowed in the integer portion of a
 number. | 
| int | getMinimumFractionDigits()Returns the minimum number of digits allowed in the fraction portion of a
 number. | 
| int | getMinimumIntegerDigits()Returns the minimum number of digits allowed in the integer portion of a
 number. | 
| static NumberFormat | getNumberInstance()Returns a general-purpose number format for the current default
  FORMATlocale. | 
| static NumberFormat | getNumberInstance(Locale inLocale)Returns a general-purpose number format for the specified locale. | 
| static NumberFormat | getPercentInstance()Returns a percentage format for the current default
  FORMATlocale. | 
| static NumberFormat | getPercentInstance(Locale inLocale)Returns a percentage format for the specified locale. | 
| RoundingMode | getRoundingMode()Gets the  RoundingModeused in this NumberFormat. | 
| int | hashCode()Overrides hashCode. | 
| boolean | isGroupingUsed()Returns true if grouping is used in this format. | 
| boolean | isParseIntegerOnly()Returns true if this format will parse numbers as integers only. | 
| Number | parse(String source)Parses text from the beginning of the given string to produce a number. | 
| abstract Number | parse(String source,
     ParsePosition parsePosition)Returns a Long if possible (e.g., within the range [Long.MIN_VALUE,
 Long.MAX_VALUE] and with no decimals), otherwise a Double. | 
| Object | parseObject(String source,
           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 | setGroupingUsed(boolean newValue)Set whether or not grouping will be used in this format. | 
| 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 | setParseIntegerOnly(boolean value)Sets whether or not numbers should be parsed as integers only. | 
| void | setRoundingMode(RoundingMode roundingMode)Sets the  RoundingModeused in this NumberFormat. | 
format, formatToCharacterIterator, parseObjectpublic static final int INTEGER_FIELD
FieldPosition, 
Constant Field Valuespublic static final int FRACTION_FIELD
FieldPosition, 
Constant Field Valuesprotected NumberFormat()
public StringBuffer format(Object number, StringBuffer toAppendTo, FieldPosition pos)
Number.
 
 This implementation extracts the number's value using
 Number.longValue() for all integral type values that
 can be converted to long without loss of information,
 including BigInteger values with a
 bit length of less than 64,
 and Number.doubleValue() for all other types. It
 then calls
 format(long,java.lang.StringBuffer,java.text.FieldPosition)
 or format(double,java.lang.StringBuffer,java.text.FieldPosition).
 This may result in loss of magnitude information and precision for
 BigInteger and BigDecimal values.
format in class Formatnumber - the number to formattoAppendTo - the StringBuffer to which the formatted
                   text is to be appendedpos - On input: an alignment field, if desired.
                   On output: the offsets of the alignment field.toAppendToIllegalArgumentException - if number is
                   null or not an instance of Number.NullPointerException - if toAppendTo or
                   pos is nullArithmeticException - if rounding is needed with rounding
                   mode being set to RoundingMode.UNNECESSARYFieldPositionpublic final Object parseObject(String source, 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.
 
 See the parse(String, ParsePosition) method for more information
 on number parsing.
parseObject in class Formatsource - A String, part of which should be parsed.pos - A ParsePosition object with index and error
            index information as described above.Number parsed from the string. In case of
         error, returns null.NullPointerException - if pos is null.public final String format(double number)
number - the double number to formatArithmeticException - if rounding is needed with rounding
                   mode being set to RoundingMode.UNNECESSARYFormat.format(java.lang.Object)public final String format(long number)
number - the long number to formatArithmeticException - if rounding is needed with rounding
                   mode being set to RoundingMode.UNNECESSARYFormat.format(java.lang.Object)public abstract StringBuffer format(double number, StringBuffer toAppendTo, FieldPosition pos)
number - the double number to formattoAppendTo - the StringBuffer to which the formatted text is to be
                   appendedpos - the field positionArithmeticException - if rounding is needed with rounding
                   mode being set to RoundingMode.UNNECESSARYFormat.format(java.lang.Object)public abstract StringBuffer format(long number, StringBuffer toAppendTo, FieldPosition pos)
number - the long number to formattoAppendTo - the StringBuffer to which the formatted text is to be
                   appendedpos - the field positionArithmeticException - if rounding is needed with rounding
                   mode being set to RoundingMode.UNNECESSARYFormat.format(java.lang.Object)public abstract Number parse(String source, ParsePosition parsePosition)
source - the String to parseparsePosition - the parse positionisParseIntegerOnly(), 
Format.parseObject(java.lang.String, java.text.ParsePosition)public Number parse(String source) throws ParseException
 See the parse(String, ParsePosition) method for more information
 on number parsing.
source - A String whose beginning should be parsed.Number parsed from the string.ParseException - if the beginning of the specified string
            cannot be parsed.public boolean isParseIntegerOnly()
true if numbers should be parsed as integers only;
         false otherwisepublic void setParseIntegerOnly(boolean value)
value - true if numbers should be parsed as integers only;
              false otherwiseisParseIntegerOnly()public static final NumberFormat getInstance()
FORMAT locale.
 This is the same as calling
 getNumberInstance().NumberFormat instance for general-purpose number
 formattingpublic static NumberFormat getInstance(Locale inLocale)
getNumberInstance(inLocale).inLocale - the desired localeNumberFormat instance for general-purpose number
 formattingpublic static final NumberFormat getNumberInstance()
FORMAT locale.
 This is equivalent to calling
 getNumberInstance(Locale.getDefault(Locale.Category.FORMAT)).
NumberFormat instance for general-purpose number
 formattingLocale.getDefault(java.util.Locale.Category), 
Locale.Category.FORMATpublic static NumberFormat getNumberInstance(Locale inLocale)
inLocale - the desired localeNumberFormat instance for general-purpose number
 formattingpublic static final NumberFormat getIntegerInstance()
FORMAT locale. The
 returned number format is configured to round floating point numbers
 to the nearest integer using half-even rounding (see RoundingMode.HALF_EVEN) for formatting,
 and to parse only the integer part of an input string (see isParseIntegerOnly).
 This is equivalent to calling
 getIntegerInstance(Locale.getDefault(Locale.Category.FORMAT)).
getRoundingMode(), 
Locale.getDefault(java.util.Locale.Category), 
Locale.Category.FORMATpublic static NumberFormat getIntegerInstance(Locale inLocale)
RoundingMode.HALF_EVEN) for formatting,
 and to parse only the integer part of an input string (see isParseIntegerOnly).inLocale - the desired localegetRoundingMode()public static final NumberFormat getCurrencyInstance()
FORMAT locale.
 This is equivalent to calling
 getCurrencyInstance(Locale.getDefault(Locale.Category.FORMAT)).
NumberFormat instance for currency formattingLocale.getDefault(java.util.Locale.Category), 
Locale.Category.FORMATpublic static NumberFormat getCurrencyInstance(Locale inLocale)
inLocale - the desired localeNumberFormat instance for currency formattingpublic static final NumberFormat getPercentInstance()
FORMAT locale.
 This is equivalent to calling
 getPercentInstance(Locale.getDefault(Locale.Category.FORMAT)).
NumberFormat instance for percentage formattingLocale.getDefault(java.util.Locale.Category), 
Locale.Category.FORMATpublic static NumberFormat getPercentInstance(Locale inLocale)
inLocale - the desired localeNumberFormat instance for percentage formattingpublic static Locale[] getAvailableLocales()
get*Instance methods of this class can return
 localized instances.
 The returned array represents the union of locales supported by the Java
 runtime and by installed
 NumberFormatProvider implementations.
 It must contain at least a Locale instance equal to
 Locale.US.NumberFormat instances are available.public int hashCode()
hashCode in class ObjectObject.equals(java.lang.Object), 
System.identityHashCode(java.lang.Object)public boolean equals(Object obj)
equals in class Objectobj - the reference object with which to compare.true if this object is the same as the obj
          argument; false otherwise.Object.hashCode(), 
HashMappublic Object clone()
public boolean isGroupingUsed()
true if grouping is used;
         false otherwisesetGroupingUsed(boolean)public void setGroupingUsed(boolean newValue)
newValue - true if grouping is used;
                 false otherwiseisGroupingUsed()public int getMaximumIntegerDigits()
setMaximumIntegerDigits(int)public void setMaximumIntegerDigits(int newValue)
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.getMaximumIntegerDigits()public int getMinimumIntegerDigits()
setMinimumIntegerDigits(int)public void setMinimumIntegerDigits(int newValue)
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.getMinimumIntegerDigits()public int getMaximumFractionDigits()
setMaximumFractionDigits(int)public void setMaximumFractionDigits(int newValue)
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.getMaximumFractionDigits()public int getMinimumFractionDigits()
setMinimumFractionDigits(int)public void setMinimumFractionDigits(int newValue)
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.getMinimumFractionDigits()public Currency getCurrency()
setCurrency.
 
 The default implementation throws
 UnsupportedOperationException.
nullUnsupportedOperationException - if the number format class
 doesn't implement currency formattingpublic void setCurrency(Currency currency)
 The default implementation throws
 UnsupportedOperationException.
currency - the new currency to be used by this number formatUnsupportedOperationException - if the number format class
 doesn't implement currency formattingNullPointerException - if currency is nullpublic RoundingMode getRoundingMode()
RoundingMode used in this NumberFormat.
 The default implementation of this method in NumberFormat
 always throws UnsupportedOperationException.
 Subclasses which handle different rounding modes should override
 this method.RoundingMode used for this NumberFormat.UnsupportedOperationException - The default implementation
     always throws this exceptionsetRoundingMode(RoundingMode)public void setRoundingMode(RoundingMode roundingMode)
RoundingMode used in this NumberFormat.
 The default implementation of this method in NumberFormat always
 throws UnsupportedOperationException.
 Subclasses which handle different rounding modes should override
 this method.roundingMode - The RoundingMode to be usedUnsupportedOperationException - The default implementation
     always throws this exceptionNullPointerException - if roundingMode is nullgetRoundingMode() Submit a bug or feature 
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