【Java】BigDecimal 比较自动化页面获取数据的大小

jwensh@2023.12.20

使用背景

对 web3 相关的数据进行计算的时候，需要进行大小加减计算，UI 自动化过程需要将数据转为自然数；页面获取的数据会有千分位 、高精度(18位)

    /*** Compares this {@code BigDecimal} with the specified* {@code BigDecimal}.  Two {@code BigDecimal} objects that are* equal in value but have a different scale (like 2.0 and 2.00)* are considered equal by this method.  This method is provided* in preference to individual methods for each of the six boolean* comparison operators ({@literal <}, ==,* {@literal >}, {@literal >=}, !=, {@literal <=}).  The* suggested idiom for performing these comparisons is:* {@code (x.compareTo(y)} &lt;<i>op</i>&gt; {@code 0)}, where* &lt;<i>op</i>&gt; is one of the six comparison operators.** @param  val {@code BigDecimal} to which this {@code BigDecimal} is*         to be compared.* @return -1, 0, or 1 as this {@code BigDecimal} is numerically*          less than, equal to, or greater than {@code val}.*/public int compareTo(BigDecimal val) {// Quick path for equal scale and non-inflated case.if (scale == val.scale) {long xs = intCompact;long ys = val.intCompact;if (xs != INFLATED && ys != INFLATED)return xs != ys ? ((xs > ys) ? 1 : -1) : 0;}int xsign = this.signum();int ysign = val.signum();if (xsign != ysign)return (xsign > ysign) ? 1 : -1;if (xsign == 0)return 0;int cmp = compareMagnitude(val);return (xsign > 0) ? cmp : -cmp;}

比较方法

• 与开发讨论过，后端业务中比较常用的是 BigDecimal
• BigDecimal 类提供 compareTo() 方法来比较两个数的大小
  • 例如：a = b 返回0 ; a < b返回-1 ; a > b返回1
  • 通过这三种比较返回的结果，我们还可以比较 a != b、a >= b和a<= b这三种情况。

import java.math.BigDecimal;public class Web3WalletTest {public static void main(String[] args) {BigDecimal a = new BigDecimal("213.003");BigDecimal b = new BigDecimal("213.004");BigDecimal c = new BigDecimal("213.003");/**** 大于 和 小于*/// a>b --> falseboolean b1 = a.compareTo(b) == 1;System.err.println("b1:" + b1);if (a.compareTo(b) == 1)System.out.println("a > b");// a<b --> trueboolean b2 = a.compareTo(b) == -1;System.err.println("b2:" + b2);if (a.compareTo(b) == -1)System.out.println("a < b");/**** 大于等于*/// a>=b --> falseboolean b3 = a.compareTo(b) > -1;System.err.println("b3:" + b3);if (a.compareTo(b) != -1)System.out.println("a >= b");// a>=c --> trueboolean b4 = a.compareTo(c) > -1;System.err.println("b4:" + b4);/**** 小于等于*/// a<=b --> trueboolean b5 = a.compareTo(b) < 1;System.err.println("b5:" + b5);if (a.compareTo(b) != 1)System.out.println("a <= b");// a<=c --> trueboolean b6 = a.compareTo(c) < 1;System.err.println("b6:" + b6);/**** 等于*/// a=c --> trueboolean b7 = a.compareTo(c) == 0;System.err.println("b7:" + b7);if (a.compareTo(b) == 0)System.out.println("a = b");if (a.compareTo(b) != 0)System.out.println("a != b");}
}

• 用例里使用的方式

BigDecimal btteBalance = new  BigDecimal(walletPage.getTokenBalance(3).getText().replace(",", ""));
Assert.assertTrue(btteBalance.compareTo(new BigDecimal("0")) > -1);