[英]Removing trailing zeros from BigDecimal in Java
I need to remove trailing zeros from BigDecimal
along with RoundingMode.HALF_UP
. 我需要从
BigDecimal
删除尾随零以及RoundingMode.HALF_UP
。 For instance, 例如,
Value Output
15.3456 <=> 15.35
15.999 <=> 16 //No trailing zeros.
15.99 <=> 15.99
15.0051 <=> 15.01
15.0001 <=> 15 //No trailing zeros.
15.000000<=> 15 //No trailing zeros.
15.00 <=> 15 //No trailing zeros.
stripTrailingZeros()
works but it returns scientific notations in situations like, stripTrailingZeros()
有效,但它会在类似的情况下返回科学记号,
new BigDecimal("600.0").setScale(2, RoundingMode.HALF_UP).stripTrailingZeros();
In this case, it returns 6E+2
. 在这种情况下,它返回
6E+2
。 I need this in a custom converter in JSF where it might be ugly for end users. 我需要在JSF中的自定义转换器中使用它,这对最终用户来说可能很难看。 So, what is the proper way of doing this?
那么,这样做的正确方法是什么?
Use toPlainString()
使用
toPlainString()
BigDecimal d = new BigDecimal("600.0").setScale(2, RoundingMode.HALF_UP).stripTrailingZeros();
System.out.println(d.toPlainString()); // Printed 600 for me
I'm not into JSF (yet), but converter might look like this: 我还没有进入JSF,但是转换器可能看起来像这样:
@FacesConverter("bigDecimalPlainDisplay")
public class BigDecimalDisplayConverter implements Converter {
@Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
throw new BigDecimal(value);
}
@Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
BigDecimal bd = (BigDecimal)value;
return bd.setScale(2, RoundingMode.HALF_UP).stripTrailingZeros().toPlainString();
}
}
and then in xhtml: 然后在xhtml中:
<h:inputText id="bigDecimalView" value="#{bigDecimalObject}"
size="20" required="true" label="Value">
<f:converter converterId="bigDecimalPlainDisplay" />
</h:inputText>
Note that stripTrailingZeros()
doesn't do very well either. 请注意,
stripTrailingZeros()
也不是很好。
On this: 在这:
val = new BigDecimal("0.0000").stripTrailingZeros();
System.out.println(val + ": plain=" + val.toPlainString());
val = new BigDecimal("40.0000").stripTrailingZeros();
System.out.println(val + ": plain=" + val.toPlainString());
val = new BigDecimal("40.50000").stripTrailingZeros();
System.out.println(val + ": plain=" + val.toPlainString());
Output (Java 7): 输出(Java 7):
0.0000: plain=0.0000
4E+1: plain=40
40.5: plain=40.5
Output (Java 8): 输出(Java 8):
0: plain=0
4E+1: plain=40
40.5: plain=40.5
The 0.0000
issue in Java 7 is fixed in Java 8 by the following java fix . Java 7中的
0.0000
问题通过以下java修复在Java 8中得到修复 。
You can also accomplish this with String.format()
, like so: 您也可以使用
String.format()
完成此操作,如下所示:
final BigDecimal b = new BigDecimal("600.0").setScale(2, RoundingMode.HALF_UP);
String f = String.format("%.0f", b);
System.out.println(f); //600
If you want to do this at your BigDecimal object and not convert it into a String with a formatter you can do it on Java 8 with 2 steps: 如果要在BigDecimal对象上执行此操作而不将其转换为带有格式化程序的String,则可以在Java 8上执行以下两个步骤:
You can try this snippet to better understand the behaviour 您可以尝试使用此代码段来更好地了解该行为
BigDecimal bigDecimal = BigDecimal.valueOf(Double.parseDouble("50"));
bigDecimal = bigDecimal.setScale(2);
bigDecimal = bigDecimal.stripTrailingZeros();
if (bigDecimal.scale()<0)
bigDecimal= bigDecimal.setScale(0);
System.out.println(bigDecimal);//50
bigDecimal = BigDecimal.valueOf(Double.parseDouble("50.20"));
bigDecimal = bigDecimal.setScale(2);
bigDecimal = bigDecimal.stripTrailingZeros();
if (bigDecimal.scale()<0)
bigDecimal= bigDecimal.setScale(0);
System.out.println(bigDecimal);//50.2
bigDecimal = BigDecimal.valueOf(Double.parseDouble("50"));
bigDecimal = bigDecimal.setScale(2);
bigDecimal = bigDecimal.stripTrailingZeros();
System.out.println(bigDecimal);//5E+1
bigDecimal = BigDecimal.valueOf(Double.parseDouble("50.20"));
bigDecimal = bigDecimal.setScale(2);
bigDecimal = bigDecimal.stripTrailingZeros();
System.out.println(bigDecimal);//50.2
You should make some calculation on the BigDecimal, and then round it half up eg 你应该对BigDecimal进行一些计算,然后将它向上舍入一半
BigDecimal toPay = new BigDecimal(1453.00005);
toPay = toPay.multiply(new BigDecimal(1)).setScale(2, RoundingMode.HALF_UP)
It worked for me. 它对我有用。
You can use DecimalFormat . 您可以使用DecimalFormat 。 For example:
例如:
BigDecimal value = new BigDecimal("15.3456").setScale(2, BigDecimal.ROUND_HALF_UP));
String valueString = new DecimalFormat("#.##").format(value);
System.out.println(valueString); //15.35
Please try yourself. 请试一试。
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