我们分析一下为什么会这样子,首先看一下round方法的API: Returns the result of rounding the argument to an integer. The result is equivalent to(long) Math.floor(d+0.5). Special cases: round(+0.0) = +0.0 round(-0.0) = +0.0 round((anything > Long.MAX_VALUE) = Long.MAX_VALUE round((anyt...
the closest integer to the argument. 即返回一个和参数相近的整型,其结果相当于(long) Math.floor(d+0.5)的值,对于Math.floor(double d)方法,其结果是d向下取整,所以对于round(-1.5)来说,它的返回值是要加上0.5再向下取整,也就是-1.5+0.5=-1.0,1.0向下取整还是1.0,所以返回的是长整型1,但是计算正数的时...
向负无穷方向舍入 ROUND_HALF_DOWN Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. 向(距离)最近的一边舍入,除非两边(的距离)是相等,如果是这样,向下舍入, 例如1.55 保留一位小数结果为1.5 ROUND_HALF_EVEN Rounding mode to round towards...
publicclassDecimalStringToInteger{publicstaticvoidmain(String[]args){// 步骤 1: 将带小数的字符串转换成浮点数StringdecimalString="12.34";// 带小数的字符串doubledecimalNumber=Double.parseDouble(decimalString);// 转换为浮点数// 步骤 2: 对浮点数进行取整操作longroundedNumber=Math.round(decimalNumber);...
roundedAmount = Integer.parseInt(String.valueOf(amount).substring(0,4) + "000"); } return roundedAmount + rounding(amount-roundedAmount); } private int rounding(int amount){ if(amount < 100){ return 100; }else if(amount < 200){ ...
void givenLargeBigDecimalWhenConvertToIntegerWithRoundingUpThenLosePrecision(double given) { BigDecimal decimal = BigDecimal.valueOf(given); int integerValue = decimal.setScale(0, RoundingMode.CEILING).intValue(); double actual = Integer.valueOf(integerValue).doubleValue(); ...
throw new IllegalArgumentException("The scale must be a positive integer or zero"); } BigDecimal b = new BigDecimal(v); return b.setScale(scale, round_mode).toString(); } } BigDecimal舍入模式(Rounding mode)介绍: BigDecimal定义了一下舍入模式,只有在作除法运算或四舍五入时才用到舍入模式,下...
Exception in thread "main" java.lang.ArithmeticException: Rounding necessary 3.5 值转换 public class BigDecimalDemo { public static void main(String[] args) { BigDecimal a = new BigDecimal(Double.toString(2.3)); BigDecimal b = new BigDecimal(10200000); ...
2)String 构造方法是完全可预知的:写入 newBigDecimal(“0.1”) 将创建一个 BigDecimal,它正好等于预期的 0.1。因此,比较而言, 通常建议优先使用String构造方法。 3)当double必须用作BigDecimal的源时,请注意,此构造方法提供了一个准确转换;它不提供与以下操作相同的结果:先使用Double.toString(double)方法,然后使用Bi...
BigDecimal is a good choice when we need to make operations on floating point numbers, avoiding rounding errors. Also, it allows us to use massive numbers that cannot be represented otherwise. BigDecimal provides various methods for conversion from other types, for example, from an Integer. As ...