下面这个可以很好地完成工作:

    public static String removeZero(double number) {
        DecimalFormat format = new DecimalFormat("#.###########");
        return format.format(number);
    }

public static String fmt(double d) {
    String val = Double.toString(d);
    String[] valArray = val.split("\\.");
    long valLong = 0;
    if(valArray.length == 2) {
        valLong = Long.parseLong(valArray[1]);
    }
     if (valLong == 0)
        return String.format("%d", (long) d);
    else
        return String.format("%s", d);
}

我必须使用这个，因为d == (long)d在SonarQube报告中给了我违例。

if (d == Math.floor(d)) {
    return String.format("%.0f", d); //Format is: 0 places after decimal point
} else {
    return Double.toString(d);
}

更多信息:https://docs.oracle.com/javase/tutorial/java/data/numberformat.html

我的观点是:

if(n % 1 == 0) {
    return String.format(Locale.US, "%.0f", n));
} else {
    return String.format(Locale.US, "%.1f", n));
}

简而言之:

如果你想摆脱尾随零和区域问题，那么你应该使用:

double myValue = 0.00000021d;

DecimalFormat df = new DecimalFormat("0", DecimalFormatSymbols.getInstance(Locale.ENGLISH));
df.setMaximumFractionDigits(340); //340 = DecimalFormat.DOUBLE_FRACTION_DIGITS

System.out.println(df.format(myValue)); //output: 0.00000021

解释:

为什么其他答案不适合我:

Double.toString() or System.out.println or FloatingDecimal.toJavaFormatString uses scientific notations if double is less than 10^-3 or greater than or equal to 10^7 double myValue = 0.00000021d; String.format("%s", myvalue); //output: 2.1E-7 by using %f, the default decimal precision is 6, otherwise you can hardcode it, but it results in extra zeros added if you have fewer decimals. Example: double myValue = 0.00000021d; String.format("%.12f", myvalue); // Output: 0.000000210000 by using setMaximumFractionDigits(0); or %.0f you remove any decimal precision, which is fine for integers/longs but not for double double myValue = 0.00000021d; System.out.println(String.format("%.0f", myvalue)); // Output: 0 DecimalFormat df = new DecimalFormat("0"); System.out.println(df.format(myValue)); // Output: 0 by using DecimalFormat, you are local dependent. In the French locale, the decimal separator is a comma, not a point: double myValue = 0.00000021d; DecimalFormat df = new DecimalFormat("0"); df.setMaximumFractionDigits(340); System.out.println(df.format(myvalue)); // Output: 0,00000021 Using the ENGLISH locale makes sure you get a point for decimal separator, wherever your program will run.

为什么使用340然后setMaximumFractionDigits?

两个原因:

setMaximumFractionDigits接受一个整数，但是它的实现有DecimalFormat允许的最大数字。DOUBLE_FRACTION_DIGITS等于340 翻倍。MIN_VALUE = 4.9E-324，因此使用340位数字，您肯定不会四舍五入的双精度和损失精度

我在JSF应用程序中使用它来格式化数字，而不带后面的零。最初的内置格式化程序要求您指定小数位数的最大数量，如果您有太多小数位数，这在这里也很有用。

/**
 * Formats the given Number as with as many fractional digits as precision
 * available.<br>
 * This is a convenient method in case all fractional digits shall be
 * rendered and no custom format / pattern needs to be provided.<br>
 * <br>
 * This serves as a workaround for {@link NumberFormat#getNumberInstance()}
 * which by default only renders up to three fractional digits.
 *
 * @param number
 * @param locale
 * @param groupingUsed <code>true</code> if grouping shall be used
 *
 * @return
 */
public static String formatNumberFraction(final Number number, final Locale locale, final boolean groupingUsed)
{
    if (number == null)
        return null;

    final BigDecimal bDNumber = MathUtils.getBigDecimal(number);

    final NumberFormat numberFormat = NumberFormat.getNumberInstance(locale);
    numberFormat.setMaximumFractionDigits(Math.max(0, bDNumber.scale()));
    numberFormat.setGroupingUsed(groupingUsed);

    // Convert back for locale percent formatter
    return numberFormat.format(bDNumber);
}

/**
 * Formats the given Number as percent with as many fractional digits as
 * precision available.<br>
 * This is a convenient method in case all fractional digits shall be
 * rendered and no custom format / pattern needs to be provided.<br>
 * <br>
 * This serves as a workaround for {@link NumberFormat#getPercentInstance()}
 * which does not renders fractional digits.
 *
 * @param number Number in range of [0-1]
 * @param locale
 *
 * @return
 */
public static String formatPercentFraction(final Number number, final Locale locale)
{
    if (number == null)
        return null;

    final BigDecimal bDNumber = MathUtils.getBigDecimal(number).multiply(new BigDecimal(100));

    final NumberFormat percentScaleFormat = NumberFormat.getPercentInstance(locale);
    percentScaleFormat.setMaximumFractionDigits(Math.max(0, bDNumber.scale() - 2));

    final BigDecimal bDNumberPercent = bDNumber.multiply(new BigDecimal(0.01));

    // Convert back for locale percent formatter
    final String strPercent = percentScaleFormat.format(bDNumberPercent);

    return strPercent;
}