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java.lang.Object
|
+----java.text.Format
|
+----java.text.NumberFormat
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:
myString = NumberFormat.getInstance().format(myNumber);
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.
NumberFormat nf = NumberFormat.getInstance();
for (int i = 0; i < a.length; ++i) {
output.println(nf.format(myNumber[i]) + "; ");
}
To format a number for a different Locale, specify it in the
call to getInstance.
NumberFormat nf = NumberFormat.getInstance(Locale.FRENCH);
You can also use a NumberFormat to parse numbers:
myNumber = nf.parse(myString);
Use getInstance or getNumberInstance to get the
normal 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 DecimalNumberFormat. 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.
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.
FRACTION_FIELD
INTEGER_FIELD
NumberFormat()
clone()
equals(Object)
format(double)
format(double, StringBuffer, FieldPosition)
format(long)
format(long, StringBuffer, FieldPosition)
format(Object, StringBuffer, FieldPosition)
getAvailableLocales()
getCurrencyInstance()
getCurrencyInstance(Locale)
getInstance()
getInstance(Locale)
getMaximumFractionDigits()
getMaximumIntegerDigits()
getMinimumFractionDigits()
getMinimumIntegerDigits()
getNumberInstance()
getNumberInstance(Locale)
getPercentInstance()
getPercentInstance(Locale)
hashCode()
isGroupingUsed()
isParseIntegerOnly()
parse(String)
parse(String, ParsePosition)
parseObject(String, ParsePosition)
setGroupingUsed(boolean)
setMaximumFractionDigits(int)
setMaximumIntegerDigits(int)
setMinimumFractionDigits(int)
setMinimumIntegerDigits(int)
setParseIntegerOnly(boolean)
INTEGER_FIELD
public static final int INTEGER_FIELD
FRACTION_FIELD
public static final int FRACTION_FIELD
NumberFormat
public NumberFormat()
format
public final StringBuffer format(Object number,
StringBuffer toAppendTo,
FieldPosition pos)
parseObject
public final Object parseObject(String source,
ParsePosition parsePosition)
format
public final String format(double number)
format
public final String format(long number)
format
public abstract StringBuffer format(double number,
StringBuffer toAppendTo,
FieldPosition pos)
format
public abstract StringBuffer format(long number,
StringBuffer toAppendTo,
FieldPosition pos)
parse
public abstract Number parse(String text,
ParsePosition parsePosition)
parse
public Number parse(String text) throws ParseException
isParseIntegerOnly
public boolean isParseIntegerOnly()
setParseIntegerOnly
public void setParseIntegerOnly(boolean value)
getInstance
public static final NumberFormat getInstance()
getInstance
public static NumberFormat getInstance(Locale inLocale)
getNumberInstance
public static final NumberFormat getNumberInstance()
getNumberInstance
public static NumberFormat getNumberInstance(Locale inLocale)
getCurrencyInstance
public static final NumberFormat getCurrencyInstance()
getCurrencyInstance
public static NumberFormat getCurrencyInstance(Locale inLocale)
getPercentInstance
public static final NumberFormat getPercentInstance()
getPercentInstance
public static NumberFormat getPercentInstance(Locale inLocale)
getAvailableLocales
public static Locale[] getAvailableLocales()
hashCode
public int hashCode()
equals
public boolean equals(Object obj)
clone
public Object clone()
isGroupingUsed
public boolean isGroupingUsed()
setGroupingUsed
public void setGroupingUsed(boolean newValue)
getMaximumIntegerDigits
public int getMaximumIntegerDigits()
setMaximumIntegerDigits
public void setMaximumIntegerDigits(int newValue)
getMinimumIntegerDigits
public int getMinimumIntegerDigits()
setMinimumIntegerDigits
public void setMinimumIntegerDigits(int newValue)
getMaximumFractionDigits
public int getMaximumFractionDigits()
setMaximumFractionDigits
public void setMaximumFractionDigits(int newValue)
getMinimumFractionDigits
public int getMinimumFractionDigits()
setMinimumFractionDigits
public void setMinimumFractionDigits(int newValue)
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