bigdecimal 小數(shù)位處理

復(fù)制代碼

public class test1_format {

public static void main(String[] args) { BigDecimal decimal = new BigDecimal("1.12345"); System.out.println(decimal); BigDecimal setScale = decimal.setScale(4,BigDecimal.ROUND_HALF_DOWN); System.out.println(setScale);

    
    BigDecimal setScale1 = decimal.setScale(4,BigDecimal.ROUND_HALF_UP);
    System.out.println(setScale1);
}

}

參數(shù)定義

ROUND_CEILING Rounding mode to round towards positive infinity. 向正無窮方向舍入

ROUND_DOWN 
Rounding mode to round towards zero. 
向零方向舍入 

ROUND_FLOOR 
Rounding mode to round towards negative infinity. 
向負(fù)無窮方向舍入 

ROUND_HALF_DOWN 
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. 
向（距離）最近的一邊舍入，除非兩邊（的距離）是相等,如果是這樣，向下舍入, 例如1.55 保留一位小數(shù)結(jié)果為1.5 

ROUND_HALF_EVEN 
Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. 
向（距離）最近的一邊舍入，除非兩邊（的距離）是相等,如果是這樣，如果保留位數(shù)是奇數(shù)，使用ROUND_HALF_UP ，如果是偶數(shù)，使用ROUND_HALF_DOWN 

ROUND_HALF_UP 
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. 
向（距離）最近的一邊舍入，除非兩邊（的距離）是相等,如果是這樣，向上舍入, 1.55保留一位小數(shù)結(jié)果為1.6 

ROUND_UNNECESSARY 
Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary. 
計(jì)算結(jié)果是精確的，不需要舍入模式 

ROUND_UP Rounding mode to round away from zero. 向遠(yuǎn)離0的方向舍入