BigDecimal的用法

@Test
public void bigDecimalPrecision(){
    System.out.println(new Double(0.07));//0.07
    System.out.println(0.06);//0.06
    System.out.println(0.06+0.01);//0.06999999999999999
    System.out.println(0.07);//0.07
    System.out.println(1.0-0.42);//0.5800000000000001
    System.out.println(4.015*100);//401.49999999999994
    System.out.println(303.1/1000);//0.30310000000000004

    BigDecimal b1 = new BigDecimal(Double.toString(0.07));//0.07
    BigDecimal b2 = new BigDecimal("0.07");//0.07
    BigDecimal b3 = new BigDecimal(0.07);//0.070000000000000006661338147750939242541790008544921875
    BigDecimal b4 = new BigDecimal(Double.valueOf(0.07));//0.070000000000000006661338147750939242541790008544921875
    BigDecimal b5 = new BigDecimal(Double.valueOf("0.07"));//0.070000000000000006661338147750939242541790008544921875
    System.out.println(b1);
    System.out.println(b2);
    System.out.println(b3);
    System.out.println(b4);
    System.out.println(b5);
    System.out.println("___________________________________");
    BigDecimal b6 = new BigDecimal(0.58);
    BigDecimal b7 = new BigDecimal(100L);
    System.out.println(b6.multiply(b7).toString());
    System.out.println(b6.multiply(b7).toPlainString());
    System.out.println("___________________________________");

    BigDecimal a = new BigDecimal(0.58);//a: 0.57999999999999996003197111349436454474925994873046875
    BigDecimal b = new BigDecimal(0.580);//b: 0.57999999999999996003197111349436454474925994873046875
    BigDecimal c = new BigDecimal("0.58");//0.58
    BigDecimal d = new BigDecimal("0.580");//0.580
    BigDecimal e = BigDecimal.valueOf(0.58);//0.58
    BigDecimal f = BigDecimal.valueOf(0.580);//0.58
    System.out.println("a: "+a);
    System.out.println("b: "+b);
    System.out.println("c: "+c);
    System.out.println("d: "+d);
    System.out.println("e: "+e);
    System.out.println("f: "+f);

    System.out.println(a.equals(b));//true
    System.out.println(a.compareTo(b));//0

    System.out.println(c.equals(d));//false
    System.out.println(c.compareTo(d));//0

    System.out.println(e.equals(f));//true
    System.out.println(e.compareTo(f));//0

    System.out.println(a.equals(c));//false
    System.out.println(a.compareTo(c));//-1

    System.out.println(b.equals(d));//false
    System.out.println(b.compareTo(d));//-1

    System.out.println(c.equals(e));//true
    System.out.println(c.compareTo(e));//0
    //toString()默认，科学计数法
    System.out.println(BigDecimal.valueOf(0.0000000058).toString());//5.8E-8
    System.out.println(BigDecimal.valueOf(0.0000000058).toPlainString());//0.000000058

}