BigDecimal 比较大小及保留两位及取非负数

//.abs()  非负数
public static BigDecimal O_PercentageStretch(BigDecimal stretch,BigDecimal stretchcontrol){
        if(stretch != null && stretch.compareTo(new BigDecimal(0)) > 0){
            return stretch.subtract(stretchcontrol).multiply(new BigDecimal(100)).divide(stretchcontrol,2,BigDecimal.ROUND_HALF_UP).abs();
        }
        return new BigDecimal(0);
}

//前提为a、b均不能为null
if(a.compareTo(b) == -1){
    System.out.println("a小于b");
}
if(a.compareTo(b) == 0){
    System.out.println("a等于b");
}
if(a.compareTo(b) == 1){
    System.out.println("a大于b");
}
if(a.compareTo(b) > -1){
    System.out.println("a大于等于b");
}
if(a.compareTo(b) < 1){
    System.out.println("a小于等于b");
}