如何在java中从float转换为bigDecimal？
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How to convert from float to bigDecimal in java?
提问by akp
How to convert from float to bigDecimal in java?
如何在java中从float转换为bigDecimal？
回答by dogbane
BigDecimal value = new BigDecimal(Float.toString(123.4f));
From the javadocs, the string constructor is generally the preferred way to convert a floatinto a BigDecimal, as it doesn't suffer from the unpredictability of the BigDecimal(double)constructor.
从javadocs来看，字符串构造函数通常是将 afloat转换为 BigDecimal的首选方法，因为它不受BigDecimal(double)构造函数不可预测性的影响。
Quote from the docs:
来自文档的引用：
Note: For values other float and double NaN and ±Infinity, this constructor is compatible with the values returned by Float.toString(float) and Double.toString(double). This is generally the preferred way to convert a float or double into a BigDecimal, as it doesn't suffer from the unpredictability of the BigDecimal(double) constructor.
注意：对于 float 和 double NaN 和 ±Infinity 以外的值，此构造函数与 Float.toString(float) 和 Double.toString(double) 返回的值兼容。这通常是将 float 或 double 转换为 BigDecimal 的首选方法，因为它不会受到 BigDecimal(double) 构造函数的不可预测性的影响。
回答by Maurice Perry
For a precision of 3 digits after the decimal point:
对于小数点后 3 位精度：
BigDecimal value = new BigDecimal(f,
new MathContext(3, RoundingMode.HALF_EVEN));
回答by Spacemonkey
float f = 45.6f;
BigDecimal bd = BigDecimal.valueOf(f);
Quote from documentations:
引用文档：
Note: This is generally the preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double).
注意：这通常是将双精度（或浮点）转换为 BigDecimal 的首选方法，因为返回的值等于从使用 Double.toString(double) 的结果构造一个 BigDecimal 的结果。
Reference: BigDecimal (Java Platform SE 6)
回答by Johnny Blaze
This is upto my knowledge :
这是据我所知：
public static BigDecimal floatToBigDecimal(Float a){
if(a == null || a.isInfinite() || a.isNaN()){
return BigDecimal.ZERO;
}
try{
return BigDecimal.valueOf(a);
}catch(Exception e){
return BigDecimal.ZERO;
}
}
*Note:This is generally the preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double).
*注意：这通常是将双精度（或浮点数）转换为 BigDecimal 的首选方法，因为返回的值等于从使用 Double.toString(double) 的结果构造一个 BigDecimal 的结果。
public static BigDecimal valueOf(double val)
公共静态 BigDecimal valueOf(double val)
Parameters:
val - double to convert to a BigDecimal.
Returns:
a BigDecimal whose value is equal to or approximately equal to the value of val.
Throws:
NumberFormatException- if val is infinite or NaN.
Since:
1.5
参数：
val - 转换为 BigDecimal 的双精度值。
返回：
一个 BigDecimal，其值等于或近似等于 val 的值。
抛出：
NumberFormatException- 如果 val 是无穷大或 NaN。
自：
1.5
I have checked whether Infinite or Not a Number, so that there is less chances of NumberFormatException
我已经检查了 Infinite 还是 Not a Number，以便减少 NumberFormatException 的机会
