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
}
}