1 package day2_15;
2
3 import org.junit.Test;
4
5 import java.math.BigDecimal;
6 import java.math.BigInteger;
7
8 /**
9 * @Author Tianhao
10 * @create 2021-02-15-16:44
11 */
12 public class BigIntegerAndBigDecimal {
13
14 @Test
15 public void test() {
16 //注意：私有构造器，是会报错的 private BigInteger(long val)
17 //调用公共构造器 public BigInteger(String val)
18 BigInteger bi = new BigInteger("4627656745686875679568678573");
19 System.out.println(bi); //4627656745686875679568678573
20
21 BigDecimal bd = new BigDecimal("123456.893");
22 System.out.println(bd);//123456.893
23
24 BigDecimal bd2 = new BigDecimal("11");
25
26 ////bd除以bd2 报错：java.lang.ArithmeticException:
27 // Non-terminating decimal expansion; no exact representable decimal result.
28 //因为结果是无限循环的小数，没有准确的结果可以表示，所以必须指定四舍五入才行
29 //System.out.println(bd.divide(bd2));
30
31 //bd除以bd2,四舍五入，默认保留3位小数
32 System.out.println(bd.divide(bd2,BigDecimal.ROUND_HALF_UP));//11223.354
33 //bd除以bd2,四舍五入，指定精度，保留15位小数
34 System.out.println(bd.divide(bd2,15,BigDecimal.ROUND_HALF_UP));//11223.353909090909091
35
36
37 }
38 }
