Java : NumberFormat 示例

Java 中的 NumberFormat (Java SE 24 & JDK 24) 及其示例。
您将找到大多数 NumberFormat 方法的代码示例。

注解 :

本文可能使用了翻译软件以方便阅读。另请查看英文原文。

简介

NumberFormat 是所有数字格式的抽象基类。该类提供了以本地化方式格式化和解析数字的接口。 (机器翻译)

Class diagram

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.format(1234000)); // 1,234,000
System.out.println(format.format(-56789)); // -56,789
System.out.println(format.format(0.123456)); // 0.123

final var number = 1234;

final var format1 = NumberFormat.getCurrencyInstance(Locale.US);
System.out.println(format1.format(number)); // $1,234.00

final var format2 = NumberFormat.getCurrencyInstance(Locale.JAPAN);
System.out.println(format2.format(number)); // ￥1,234

final var number = 10000000;

final var format1 = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.LONG);
System.out.println(format1.format(number)); // 10 million

final var format2 = NumberFormat.getCompactNumberInstance(Locale.JAPAN, NumberFormat.Style.SHORT);
System.out.println(format2.format(number)); // 1000万

Fields

static final int FRACTION_FIELD

用于构造 FieldPosition 对象的字段常量。 (机器翻译)

final var number = 123.456;

final var format = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format.format(number)); // 123.456

{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.INTEGER_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 6
    System.out.println(pos.getEndIndex()); // 9
}
{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.FRACTION_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 10
    System.out.println(pos.getEndIndex()); // 13
}

static final int INTEGER_FIELD

用于构造 FieldPosition 对象的字段常量。 (机器翻译)

final var number = 123.456;

final var format = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format.format(number)); // 123.456

{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.INTEGER_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 6
    System.out.println(pos.getEndIndex()); // 9
}
{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.FRACTION_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 10
    System.out.println(pos.getEndIndex()); // 13
}

Constructors

NumberFormat ()

唯一建造者。 (机器翻译)

I think it's rare to create a subclass of NumberFormat. Therefore, the code example is omitted.

Methods

Object clone ()

覆盖 Cloneable。 (机器翻译)

final var number = 1.234;

final var format = NumberFormat.getNumberInstance();
format.setMaximumFractionDigits(2);
System.out.println(format.format(number)); // 1.23

if (format.clone() instanceof NumberFormat cloned) {
    System.out.println(cloned.format(number)); // 1.23
    System.out.println(cloned.equals(format)); // true
}

boolean equals (Object obj)

将指定对象与此 NumberFormat 进行比较以确定其是否相等。 (机器翻译)

final var format1 = NumberFormat.getNumberInstance();
final var format2 = NumberFormat.getCurrencyInstance();

System.out.println(format1.equals(format2)); // false

final var format1 = NumberFormat.getNumberInstance();
final var format2 = NumberFormat.getNumberInstance();

System.out.println(format1.equals(format2)); // true

format1.setMaximumFractionDigits(2);
System.out.println(format1.equals(format2)); // false

final String format (double number)

格式的专业化。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1.234;

final var format = NumberFormat.getNumberInstance();
System.out.println(format.format(number)); // 1.234

format.setMaximumFractionDigits(2);
System.out.println(format.format(number)); // 1.23

format.setMinimumIntegerDigits(3);
System.out.println(format.format(number)); // 001.23

abstract StringBuffer format (double number, StringBuffer toAppendTo, FieldPosition pos)

格式的专业化。 (机器翻译)

final var number = 123.456;

final var format = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format.format(number)); // 123.456

{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.INTEGER_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 6
    System.out.println(pos.getEndIndex()); // 9
}
{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.FRACTION_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 123.456

    System.out.println(pos.getBeginIndex()); // 10
    System.out.println(pos.getEndIndex()); // 13
}

final String format (long number)

格式的专业化。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1234L;

final var format1 = NumberFormat.getCurrencyInstance();
System.out.println(format1.format(number)); // $1,234.00

final var format2 = NumberFormat.getCurrencyInstance(Locale.JAPAN);
System.out.println(format2.format(number)); // ￥1,234

abstract StringBuffer format (long number, StringBuffer toAppendTo, FieldPosition pos)

格式的专业化。 (机器翻译)

final var format = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.SHORT);
format.setMinimumFractionDigits(2);

final var number = 12340L;
System.out.println(format.format(number)); // 12.34K

{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.INTEGER_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 12.34K

    System.out.println(pos.getBeginIndex()); // 6
    System.out.println(pos.getEndIndex()); // 8
}
{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.FRACTION_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 12.34K

    System.out.println(pos.getBeginIndex()); // 9
    System.out.println(pos.getEndIndex()); // 11
}

StringBuffer format (Object number, StringBuffer toAppendTo, FieldPosition pos)

格式化数字并将结果文本附加到给定的字符串缓冲区。 (机器翻译)

final var format = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.SHORT);
format.setMinimumFractionDigits(2);

final var number = new BigInteger("12340000000000");
System.out.println(format.format(number)); // 12.34T

{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.INTEGER_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 12.34T

    System.out.println(pos.getBeginIndex()); // 6
    System.out.println(pos.getEndIndex()); // 8
}
{
    final var sb = new StringBuffer("num = ");
    System.out.println(sb); // num =

    final var pos = new FieldPosition(NumberFormat.FRACTION_FIELD);
    final var ret = format.format(number, sb, pos);
    System.out.println(ret); // num = 12.34T

    System.out.println(pos.getBeginIndex()); // 9
    System.out.println(pos.getEndIndex()); // 11
}

static Locale[] getAvailableLocales ()

返回此类的 get*Instance 方法可以返回本地化实例的所有语言环境的数组。 (机器翻译)

final var locales = NumberFormat.getAvailableLocales();

for (final var locale : locales) {
    System.out.println(locale.toLanguageTag());
}

// Result
// ↓
//und
//sr-ME
//ksh
//fr-SY
//fr-TD
//fr-TG
//ccp
//...

static NumberFormat getCompactNumberInstance ()

返回具有“SHORT”格式样式的默认 FORMAT 语言环境的紧凑数字格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 10000000;

final var format1 = NumberFormat.getCompactNumberInstance();
System.out.println(format1.format(number)); // 10M

final var format2 = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.SHORT);
System.out.println(format2.format(number)); // 10M

final var format3 = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.LONG);
System.out.println(format3.format(number)); // 10 million

final var format4 = NumberFormat.getCompactNumberInstance(Locale.JAPAN, NumberFormat.Style.SHORT);
System.out.println(format4.format(number)); // 1000万

static NumberFormat getCompactNumberInstance (Locale locale, NumberFormat.Style formatStyle)

返回指定语言环境和 formatStyle 的紧凑数字格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 10000000;

final var format1 = NumberFormat.getCompactNumberInstance();
System.out.println(format1.format(number)); // 10M

final var format2 = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.SHORT);
System.out.println(format2.format(number)); // 10M

final var format3 = NumberFormat.getCompactNumberInstance(Locale.US, NumberFormat.Style.LONG);
System.out.println(format3.format(number)); // 10 million

final var format4 = NumberFormat.getCompactNumberInstance(Locale.JAPAN, NumberFormat.Style.SHORT);
System.out.println(format4.format(number)); // 1000万

Currency getCurrency ()

获取格式化货币值时此数字格式所使用的货币。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1234;

final var format1 = NumberFormat.getCurrencyInstance();
System.out.println(format1.format(number)); // $1,234.00
System.out.println(format1.getCurrency()); // USD
System.out.println(format1.getMinimumFractionDigits()); // 2

final var format2 = NumberFormat.getCurrencyInstance(Locale.JAPAN);
System.out.println(format2.format(number)); // ￥1,234
System.out.println(format2.getCurrency()); // JPY
System.out.println(format2.getMinimumFractionDigits()); // 0

static final NumberFormat getCurrencyInstance ()

返回当前默认 FORMAT 语言环境的货币格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1234;

final var format1 = NumberFormat.getCurrencyInstance();
System.out.println(format1.format(number)); // $1,234.00
System.out.println(format1.getCurrency()); // USD
System.out.println(format1.getMinimumFractionDigits()); // 2

final var format2 = NumberFormat.getCurrencyInstance(Locale.JAPAN);
System.out.println(format2.format(number)); // ￥1,234
System.out.println(format2.getCurrency()); // JPY
System.out.println(format2.getMinimumFractionDigits()); // 0

static NumberFormat getCurrencyInstance (Locale inLocale)

返回指定语言环境的货币格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1234;

final var format1 = NumberFormat.getCurrencyInstance();
System.out.println(format1.format(number)); // $1,234.00
System.out.println(format1.getCurrency()); // USD
System.out.println(format1.getMinimumFractionDigits()); // 2

final var format2 = NumberFormat.getCurrencyInstance(Locale.JAPAN);
System.out.println(format2.format(number)); // ￥1,234
System.out.println(format2.getCurrency()); // JPY
System.out.println(format2.getMinimumFractionDigits()); // 0

static final NumberFormat getInstance ()

返回当前默认 FORMAT 语言环境的通用数字格式。 (机器翻译)

This method is equivalent to getNumberInstance().

static NumberFormat getInstance (Locale inLocale)

返回指定语言环境的通用数字格式。 (机器翻译)

This method is equivalent to getNumberInstance(inLocale).

static final NumberFormat getIntegerInstance ()

返回当前默认 FORMAT 语言环境的整数格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getIntegerInstance();
System.out.println(format1.getRoundingMode()); // HALF_EVEN
System.out.println(format1.isParseIntegerOnly()); // true

System.out.println(format1.format(12345678)); // 12,345,678
System.out.println(format1.format(9.9)); // 10

final var format2 = NumberFormat.getIntegerInstance(Locale.GERMANY);
System.out.println(format2.format(12345678)); // 12.345.678
System.out.println(format2.format(9.9)); // 10

static NumberFormat getIntegerInstance (Locale inLocale)

返回指定语言环境的整数格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getIntegerInstance();
System.out.println(format1.getRoundingMode()); // HALF_EVEN
System.out.println(format1.isParseIntegerOnly()); // true

System.out.println(format1.format(12345678)); // 12,345,678
System.out.println(format1.format(9.9)); // 10

final var format2 = NumberFormat.getIntegerInstance(Locale.GERMANY);
System.out.println(format2.format(12345678)); // 12.345.678
System.out.println(format2.format(9.9)); // 10

int getMaximumFractionDigits ()

返回数字小数部分允许的最大位数。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumFractionDigits()); // 0
System.out.println(format.getMaximumFractionDigits()); // 3

System.out.println(format.format(0.01234)); // 0.012
System.out.println(format.format(456.0)); // 456

format.setMinimumFractionDigits(1);
format.setMaximumFractionDigits(4);

System.out.println(format.getMinimumFractionDigits()); // 1
System.out.println(format.getMaximumFractionDigits()); // 4

System.out.println(format.format(0.01234)); // 0.0123
System.out.println(format.format(456.0)); // 456.0

int getMaximumIntegerDigits ()

返回数字的整数部分允许的最大位数。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumIntegerDigits()); // 1
System.out.println(format.getMaximumIntegerDigits()); // 2147483647

System.out.println(format.format(1234567890)); // 1,234,567,890
System.out.println(format.format(1)); // 1

format.setMinimumIntegerDigits(3);
format.setMaximumIntegerDigits(8);

System.out.println(format.getMinimumIntegerDigits()); // 3
System.out.println(format.getMaximumIntegerDigits()); // 8

System.out.println(format.format(1234567890)); // 34,567,890
System.out.println(format.format(1)); // 001

int getMinimumFractionDigits ()

返回数字小数部分允许的最小位数。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumFractionDigits()); // 0
System.out.println(format.getMaximumFractionDigits()); // 3

System.out.println(format.format(0.01234)); // 0.012
System.out.println(format.format(456.0)); // 456

format.setMinimumFractionDigits(1);
format.setMaximumFractionDigits(4);

System.out.println(format.getMinimumFractionDigits()); // 1
System.out.println(format.getMaximumFractionDigits()); // 4

System.out.println(format.format(0.01234)); // 0.0123
System.out.println(format.format(456.0)); // 456.0

int getMinimumIntegerDigits ()

返回数字的整数部分允许的最小位数。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumIntegerDigits()); // 1
System.out.println(format.getMaximumIntegerDigits()); // 2147483647

System.out.println(format.format(1234567890)); // 1,234,567,890
System.out.println(format.format(1)); // 1

format.setMinimumIntegerDigits(3);
format.setMaximumIntegerDigits(8);

System.out.println(format.getMinimumIntegerDigits()); // 3
System.out.println(format.getMaximumIntegerDigits()); // 8

System.out.println(format.format(1234567890)); // 34,567,890
System.out.println(format.format(1)); // 001

static final NumberFormat getNumberInstance ()

返回当前默认 FORMAT 语言环境的通用数字格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getNumberInstance();

System.out.println(format1.format(12345678)); // 12,345,678
System.out.println(format1.format(0.123)); // 0.123

final var format2 = NumberFormat.getNumberInstance(Locale.GERMANY);

System.out.println(format2.format(12345678)); // 12.345.678
System.out.println(format2.format(0.123)); // 0,123

static NumberFormat getNumberInstance (Locale inLocale)

返回指定语言环境的通用数字格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getNumberInstance();

System.out.println(format1.format(12345678)); // 12,345,678
System.out.println(format1.format(0.123)); // 0.123

final var format2 = NumberFormat.getNumberInstance(Locale.GERMANY);

System.out.println(format2.format(12345678)); // 12.345.678
System.out.println(format2.format(0.123)); // 0,123

static final NumberFormat getPercentInstance ()

返回当前默认 FORMAT 语言环境的百分比格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getPercentInstance();
System.out.println(format1.format(0.75)); // 75%

final var format2 = NumberFormat.getPercentInstance(Locale.FRANCE);
System.out.println(format2.format(0.75)); // 75 %

static NumberFormat getPercentInstance (Locale inLocale)

返回指定语言环境的百分比格式。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format1 = NumberFormat.getPercentInstance();
System.out.println(format1.format(0.75)); // 75%

final var format2 = NumberFormat.getPercentInstance(Locale.FRANCE);
System.out.println(format2.format(0.75)); // 75 %

RoundingMode getRoundingMode ()

获取此 NumberFormat 中使用的 RoundingMode。 (机器翻译)

final var format = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format.getMaximumFractionDigits()); // 3
System.out.println(format.getRoundingMode()); // HALF_EVEN

System.out.println(format.format(0.1114)); // 0.111
System.out.println(format.format(0.1115)); // 0.112
System.out.println(format.format(0.1116)); // 0.112

format.setRoundingMode(RoundingMode.UP);
System.out.println(format.getRoundingMode()); // UP

System.out.println(format.format(0.1114)); // 0.112
System.out.println(format.format(0.1115)); // 0.112
System.out.println(format.format(0.1116)); // 0.112

format.setRoundingMode(RoundingMode.DOWN);
System.out.println(format.getRoundingMode()); // DOWN

System.out.println(format.format(0.1114)); // 0.111
System.out.println(format.format(0.1115)); // 0.111
System.out.println(format.format(0.1116)); // 0.111

int hashCode ()

返回此 NumberFormat 的哈希码。 (机器翻译)

final var format1 = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format1.hashCode()); // 423132

final var format2 = NumberFormat.getNumberInstance(Locale.JAPAN);
System.out.println(format2.hashCode()); // 423132

final var format3 = NumberFormat.getCurrencyInstance(Locale.US);
System.out.println(format3.hashCode()); // 423168

boolean isGroupingUsed ()

如果以这种格式使用分组，则返回 true。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isGroupingUsed()); // true

System.out.println(format.format(1234567)); // 1,234,567

format.setGroupingUsed(false);
System.out.println(format.isGroupingUsed()); // false

System.out.println(format.format(1234567)); // 1234567

boolean isParseIntegerOnly ()

如果此格式仅将数字解析为整数，则返回 true。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isParseIntegerOnly()); // false

final var ret1 = format.parse("123");
System.out.println(ret1); // 123

final var ret2 = format.parse("4.567");
System.out.println(ret2); // 4.567

format.setParseIntegerOnly(true);
System.out.println(format.isParseIntegerOnly()); // true

final var ret3 = format.parse("4.567");
System.out.println(ret3); // 4

boolean isStrict ()

如果此格式将严格解析数字，则返回 true；否则返回 false。 (机器翻译)

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isStrict()); // false

final var ret = format.parse("75%");
System.out.println(ret); // 75

format.setStrict(true);
System.out.println(format.isStrict()); // true

try {
    var _ = format.parse("75%");
} catch (ParseException e) {
    System.out.println(e);
}

// Result
// ↓
//java.text.ParseException: Unparseable number: "75%"

Number parse (String source)

从给定字符串的开头解析文本以生成数字。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

final var ret1 = format.parse("123,000");
System.out.println(ret1); // 123000
System.out.println(ret1.getClass().getSimpleName()); // Long

final var ret2 = format.parse("0.123");
System.out.println(ret2); // 0.123
System.out.println(ret2.getClass().getSimpleName()); // Double

final var format = NumberFormat.getPercentInstance();

final var ret = format.parse("75%");
System.out.println(ret); // 0.75
System.out.println(ret.getClass().getSimpleName()); // Double

final var format = NumberFormat.getCompactNumberInstance();

final var ret = format.parse("100K");
System.out.println(ret); // 100000
System.out.println(ret.getClass().getSimpleName()); // Long

abstract Number parse (String source, ParsePosition parsePosition)

从给定字符串的开头解析文本以生成数字。 (机器翻译)

final var format = NumberFormat.getNumberInstance(Locale.US);

final var source = "123 456";
final var pos = new ParsePosition(0);

final var ret1 = format.parse(source, pos);
System.out.println(ret1); // 123
System.out.println(pos.getIndex()); // 3

pos.setIndex(pos.getIndex() + 1);

final var ret2 = format.parse(source, pos);
System.out.println(ret2); // 456
System.out.println(pos.getIndex()); // 7

final var ret3 = format.parse(source, pos);
System.out.println(ret3); // null

final Object parseObject (String source, ParsePosition pos)

解析给定字符串中的文本以生成对象。 (机器翻译)

final var format = NumberFormat.getNumberInstance(Locale.US);

final var source = "123 456";
final var pos = new ParsePosition(0);

final var ret1 = format.parseObject(source, pos);
System.out.println(ret1); // 123
System.out.println(pos.getIndex()); // 3

pos.setIndex(pos.getIndex() + 1);

final var ret2 = format.parseObject(source, pos);
System.out.println(ret2); // 456
System.out.println(pos.getIndex()); // 7

final var ret3 = format.parseObject(source, pos);
System.out.println(ret3); // null

void setCurrency (Currency currency)

设置格式化货币值时此数字格式所使用的货币。 (机器翻译)

Please see also : getCurrency()

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var number = 1234;

final var format = NumberFormat.getCurrencyInstance();
System.out.println(format.format(number)); // $1,234.00
System.out.println(format.getCurrency()); // USD

format.setCurrency(Currency.getInstance(Locale.JAPAN));
format.setMinimumFractionDigits(0);

System.out.println(format.format(number)); // ¥1,234
System.out.println(format.getCurrency()); // JPY

void setGroupingUsed (boolean newValue)

设置此格式是否使用分组。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isGroupingUsed()); // true

System.out.println(format.format(1234567)); // 1,234,567

format.setGroupingUsed(false);
System.out.println(format.isGroupingUsed()); // false

System.out.println(format.format(1234567)); // 1234567

void setMaximumFractionDigits (int newValue)

设置数字小数部分允许的最大位数。maximumFractionDigits 必须≥minimumFractionDigits。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumFractionDigits()); // 0
System.out.println(format.getMaximumFractionDigits()); // 3

System.out.println(format.format(0.01234)); // 0.012
System.out.println(format.format(456.0)); // 456

format.setMinimumFractionDigits(1);
format.setMaximumFractionDigits(4);

System.out.println(format.getMinimumFractionDigits()); // 1
System.out.println(format.getMaximumFractionDigits()); // 4

System.out.println(format.format(0.01234)); // 0.0123
System.out.println(format.format(456.0)); // 456.0

void setMaximumIntegerDigits (int newValue)

设置数字的整数部分允许的最大位数。maximumIntegerDigits 必须≥minimumIntegerDigits。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumIntegerDigits()); // 1
System.out.println(format.getMaximumIntegerDigits()); // 2147483647

System.out.println(format.format(1234567890)); // 1,234,567,890
System.out.println(format.format(1)); // 1

format.setMinimumIntegerDigits(3);
format.setMaximumIntegerDigits(8);

System.out.println(format.getMinimumIntegerDigits()); // 3
System.out.println(format.getMaximumIntegerDigits()); // 8

System.out.println(format.format(1234567890)); // 34,567,890
System.out.println(format.format(1)); // 001

void setMinimumFractionDigits (int newValue)

设置数字小数部分允许的最小位数。minimumFractionDigits 必须 ≤ maximumFractionDigits。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumFractionDigits()); // 0
System.out.println(format.getMaximumFractionDigits()); // 3

System.out.println(format.format(0.01234)); // 0.012
System.out.println(format.format(456.0)); // 456

format.setMinimumFractionDigits(1);
format.setMaximumFractionDigits(4);

System.out.println(format.getMinimumFractionDigits()); // 1
System.out.println(format.getMaximumFractionDigits()); // 4

System.out.println(format.format(0.01234)); // 0.0123
System.out.println(format.format(456.0)); // 456.0

void setMinimumIntegerDigits (int newValue)

设置数字整数部分允许的最小位数。minimumIntegerDigits 必须 ≤ maximumIntegerDigits。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();

System.out.println(format.getMinimumIntegerDigits()); // 1
System.out.println(format.getMaximumIntegerDigits()); // 2147483647

System.out.println(format.format(1234567890)); // 1,234,567,890
System.out.println(format.format(1)); // 1

format.setMinimumIntegerDigits(3);
format.setMaximumIntegerDigits(8);

System.out.println(format.getMinimumIntegerDigits()); // 3
System.out.println(format.getMaximumIntegerDigits()); // 8

System.out.println(format.format(1234567890)); // 34,567,890
System.out.println(format.format(1)); // 001

void setParseIntegerOnly (boolean value)

设置是否仅将数字解析为整数。 (机器翻译)

System.out.println(Locale.getDefault().toLanguageTag()); // en-US

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isParseIntegerOnly()); // false

final var ret1 = format.parse("123");
System.out.println(ret1); // 123

final var ret2 = format.parse("4.567");
System.out.println(ret2); // 4.567

format.setParseIntegerOnly(true);
System.out.println(format.isParseIntegerOnly()); // true

final var ret3 = format.parse("4.567");
System.out.println(ret3); // 4

void setRoundingMode (RoundingMode roundingMode)

设置此 NumberFormat 中使用的 RoundingMode。 (机器翻译)

final var format = NumberFormat.getNumberInstance(Locale.US);
System.out.println(format.getMaximumFractionDigits()); // 3
System.out.println(format.getRoundingMode()); // HALF_EVEN

System.out.println(format.format(0.1114)); // 0.111
System.out.println(format.format(0.1115)); // 0.112
System.out.println(format.format(0.1116)); // 0.112

format.setRoundingMode(RoundingMode.UP);
System.out.println(format.getRoundingMode()); // UP

System.out.println(format.format(0.1114)); // 0.112
System.out.println(format.format(0.1115)); // 0.112
System.out.println(format.format(0.1116)); // 0.112

format.setRoundingMode(RoundingMode.DOWN);
System.out.println(format.getRoundingMode()); // DOWN

System.out.println(format.format(0.1114)); // 0.111
System.out.println(format.format(0.1115)); // 0.111
System.out.println(format.format(0.1116)); // 0.111

void setStrict (boolean strict)

更改解析的宽大处理值。 (机器翻译)

final var format = NumberFormat.getNumberInstance();
System.out.println(format.isStrict()); // false

final var ret = format.parse("75%");
System.out.println(ret); // 75

format.setStrict(true);
System.out.println(format.isStrict()); // true

try {
    var _ = format.parse("75%");
} catch (ParseException e) {
    System.out.println(e);
}

// Result
// ↓
//java.text.ParseException: Unparseable number: "75%"

Methods declared in Format

format, formatToCharacterIterator, parseObject

请参阅下面的链接。

Format 示例

API 示例
- Format
  - NumberFormat

Java : NumberFormat 示例

简介

Fields

static final int FRACTION_FIELD

static final int INTEGER_FIELD

Constructors

NumberFormat ()

Methods

Object clone ()

boolean equals (Object obj)

final String format (double number)

abstract StringBuffer format (double number, StringBuffer toAppendTo, FieldPosition pos)

final String format (long number)

abstract StringBuffer format (long number, StringBuffer toAppendTo, FieldPosition pos)

StringBuffer format (Object number, StringBuffer toAppendTo, FieldPosition pos)

static Locale[] getAvailableLocales ()

static NumberFormat getCompactNumberInstance ()

static NumberFormat getCompactNumberInstance (Locale locale, NumberFormat.Style formatStyle)

Currency getCurrency ()

static final NumberFormat getCurrencyInstance ()

static NumberFormat getCurrencyInstance (Locale inLocale)

static final NumberFormat getInstance ()

static NumberFormat getInstance (Locale inLocale)

static final NumberFormat getIntegerInstance ()

static NumberFormat getIntegerInstance (Locale inLocale)

int getMaximumFractionDigits ()

int getMaximumIntegerDigits ()

int getMinimumFractionDigits ()

int getMinimumIntegerDigits ()

static final NumberFormat getNumberInstance ()

static NumberFormat getNumberInstance (Locale inLocale)

static final NumberFormat getPercentInstance ()

static NumberFormat getPercentInstance (Locale inLocale)

RoundingMode getRoundingMode ()

int hashCode ()

boolean isGroupingUsed ()

boolean isParseIntegerOnly ()

boolean isStrict ()

Number parse (String source)

abstract Number parse (String source, ParsePosition parsePosition)

final Object parseObject (String source, ParsePosition pos)

void setCurrency (Currency currency)

void setGroupingUsed (boolean newValue)

void setMaximumFractionDigits (int newValue)

void setMaximumIntegerDigits (int newValue)

void setMinimumFractionDigits (int newValue)

void setMinimumIntegerDigits (int newValue)

void setParseIntegerOnly (boolean value)

void setRoundingMode (RoundingMode roundingMode)

void setStrict (boolean strict)

Methods declared in Format

format, formatToCharacterIterator, parseObject

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