java 高精度

package BigDecimal;

import java.math.BigDecimal;
import java.lang.Object;

public class BigDecimalTest {

	public static void add(double i, double j){

		System.out.println(i+j);//2.5999999999999996

		BigDecimal bi = new BigDecimal(1.2);
		BigDecimal bj = new BigDecimal(1.4);
		System.out.println(bj);//1.399999999999999911182158029987476766109466552734375
		System.out.println(bi);//1.1999999999999999555910790149937383830547332763671875
		System.out.println(bi.add(bj));//2.5999999999999998667732370449812151491641998291015625

		BigDecimal bis = new BigDecimal("1.2");
		BigDecimal bjs = new BigDecimal("1.4");
		System.out.println(bjs); //1.2
		System.out.println(bis);//1.4
		//bis.add(bjs).doubleValue()
		System.out.println("---:"+bis.add(bjs));//2.6

		String si = String.valueOf(i);
		BigDecimal bsi = new BigDecimal(si);
		System.out.println(bsi);//1.2

		BigDecimal bsii = new BigDecimal(Double.toString(i));
		System.out.println(bsii);//1.2
	}

	public static void sub(double i, double j){

		System.out.println(j-i);

		System.out.println(new BigDecimal("1.4").subtract(new BigDecimal("1.2")));// 0.9

	}

	public static void mul(double i, double j){

		System.out.println(j*i);//1.68

	}

	public static void div(double i, double j){

		System.out.println(i/j);//1.68

	}
	public static void main(String args[]) {

		double i = 1.2;
		double j = 1.4;
		//加法操作
		add(i,j);

		//减法操作
		//sub(i, j);

		//乘法操作
		//mul(i, j);

		//除法操作
		div(2.4, 1.2);//2.0
	}
}

　　

package BigDecimal;

import java.math.BigDecimal;

public class FloatTest {

	public static void main(String[] args) {

		float i = 1.4f;
		float j = 1.2f;

		System.out.println(i - j);//0.19999993

		BigDecimal bi = new BigDecimal(i);
		System.out.println(bi);//1.39999997615814208984375

		BigDecimal bis = new BigDecimal(String.valueOf(i));
		System.out.println(bis); //1.4
		BigDecimal bjs = new BigDecimal(String.valueOf(j));
		System.out.println(bjs); //1.2

		System.out.println(bis.subtract(bjs).floatValue()); //0.2
		System.out.println(bis.subtract(bjs).doubleValue());//0.2
	}
}