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 }