Java BigInteger简单使用示例

Java BigInteger**简单使用示例**，如有更进一步的需求，请自行查阅Api。

package commonApi;

import java.math.*;
import java.util.Random;
import java.util.Scanner;

/*
 * BigInteger|BigDecimal 的 简单使用实例
 */
public class BigIntegerDemo {

    public static void main(String[] args) {

        //构造方法
        BigInteger bi = BigInteger.valueOf(100l);

//      BigInteger bi_ = new BigInteger("100");

        BigDecimal bd = BigDecimal.valueOf(101.7); 

//      BigDecimal  bd_ = new BigDecimal("101");

//      BigDecimal bd_ = new BigDecimal(101);

        // 输入输出

        Scanner scan =  new Scanner(System.in);

        bi = scan.nextBigInteger();
        bd = scan.nextBigDecimal();

        System.out.println(bi.toString()+" , "+bd.toString());


        //相关函数|使用示例

        System.out.println("构造两个BigInteger:");

        //public BigInteger(int numBits,Random rnd) 生成1~2^numBits-1 之间的一个数

        BigInteger bi1 = new BigInteger(55, new Random());

        BigInteger bi2 = new BigInteger(new byte[]{3,2,3});

        System.out.println("bi1 = "+bi1.toString()+" , bi2 = "+bi2.toString());

        //加减乘除使用示例
        System.out.println("bi1 + bi2 = "+bi1.add(bi2).toString());
        System.out.println("bi1 - bi2 = "+bi1.subtract(bi2).toString());
        System.out.println("bi1 * bi2 = "+bi1.multiply(bi2).toString());
        System.out.println("bi1 / bi2 = "+bi1.divide(bi2).toString());
        System.out.println("bi1 ^ 2 = "+bi1.pow(2).toString());
        System.out.println("bi1 % bi2 = "+bi1.remainder(bi2));

        //比较大小
        if(bi1.compareTo(bi2) > 0){
            System.out.println("greater !");
        }else{
            System.out.println("no more than !");
        }

        //相反数
        BigInteger bi3 = bi1.negate();
        System.out.println(bi3.toString());
        //绝对值
        System.out.println(bi3.abs().toString());

    }

}