BigInteger 和 BigDecimal

package day2_15;

import org.junit.Test;

import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * @Author Tianhao
 * @create 2021-02-15-16:44
 */
public class BigIntegerAndBigDecimal {

    @Test
    public void test() {
        //注意：私有构造器，是会报错的 private BigInteger(long val)
        //调用公共构造器 public BigInteger(String val)
        BigInteger bi = new BigInteger("4627656745686875679568678573");
        System.out.println(bi);           //4627656745686875679568678573

        BigDecimal bd = new BigDecimal("123456.893");
        System.out.println(bd);//123456.893

        BigDecimal bd2 = new BigDecimal("11");

        ////bd除以bd2  报错：java.lang.ArithmeticException:
        // Non-terminating decimal expansion; no exact representable decimal result.
        //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
        //System.out.println(bd.divide(bd2));

        //bd除以bd2,四舍五入，默认保留3位小数
        System.out.println(bd.divide(bd2,BigDecimal.ROUND_HALF_UP));//11223.354
        //bd除以bd2,四舍五入，指定精度，保留15位小数
        System.out.println(bd.divide(bd2,15,BigDecimal.ROUND_HALF_UP));//11223.353909090909091


    }
}