Bigdecimal类型使用 保留小数位

bigdecimal 保留小数位

实际开发中,会出现数值为空的状况,这时类的getter和setter方法应该判断是否传入为空或者直接在Bigdecimal 类型属性上初始化，如：

 private BigDecimal income = new BigDecimal(0);  //收入
 private BigDecimal cess = new BigDecimal(0);  //税额
 private BigDecimal comm = new BigDecimal(0);  // 总费用 

 BigDecimal类型若是须要运算则要转换类型为double或Double才行,计算完成后再转换回Bigdecimal类型，这时BigDecimal里面的值有多是不少位小数位，若是但愿无论计算结果，当我得到某一对象Bigdecimal类型属性的值时，统一都是2位小数时,要控制该属性的getter或setter方法，如：

控制getter() ,须要配合上面的属性字段的初始化

public BigDecimal getCess() {
  return cess.setScale(2, BigDecimal.ROUND_HALF_UP);
 }

或者控制setter()
 public void setCess(BigDecimal cess) {
    if(null == cess){
      this.cess = cess.setScale(2, BigDecimal.ROUND_HALF_UP);
    }else{
      this.cess = null;
    }
 }

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);
    }
}

 

参数定义

ROUND_CEILING 
Rounding mode to round towards positive infinity. 
向正无穷方向舍入 

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,若是是这样，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 the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. 
向（距离）最近的一边舍入，除非两边（的距离）是相等,若是是这样，若是保留位数是奇数，使用ROUND_HALF_UP ，若是是偶数，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（距离）最近的一边舍入，除非两边（的距离）是相等,若是是这样，向上舍入, 1.55保留一位小数结果为1.6 


ROUND_UNNECESSARY 
Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary. 
计算结果是精确的，不须要舍入模式 


ROUND_UP 
Rounding mode to round away from zero. 
向远离0的方向舍入