Java中BigDecimal精度和相等比较的坑

//new 传进去一个double
BigDecimal newZero = new BigDecimal(0.0);
System.out.println(BigDecimal.ZERO.equals(newZero));
 
//new 传进去一个字符串
BigDecimal stringNewZero = new BigDecimal("0.0");
System.out.println(BigDecimal.ZERO.equals(stringNewZero));
 
//valueOf 传进去一个double
BigDecimal noScaleZero = BigDecimal.valueOf(0.0);
System.out.println(BigDecimal.ZERO.equals(noScaleZero));
 
//valueOf 传进去一个double，再手动设置精度为1
BigDecimal scaleZero = BigDecimal.valueOf(0.0).setScale(1);
System.out.println(BigDecimal.ZERO.equals(scaleZero));

public boolean equals(Object x) {
 //类型不同，直接返回false
 if (!(x instanceof BigDecimal))
  return false;
 BigDecimal xDec = (BigDecimal) x;
 //同一个对象，直接返回true
 if (x == this)
  return true;
 //精度不同，直接返回false！！
 if (scale != xDec.scale)
  return false;
 long s = this.intCompact;
 long xs = xDec.intCompact;
 if (s != INFLATED) {
  if (xs == INFLATED)
   xs = compactValFor(xDec.intVal);
  return xs == s;
 } else if (xs != INFLATED)
  return xs == compactValFor(this.intVal);
 
 return this.inflated().equals(xDec.inflated());
}

// Cache of common small BigDecimal values.
private static final BigDecimal zeroThroughTen[] = {
 new BigDecimal(BigInteger.ZERO,  0, 0, 1),
 new BigDecimal(BigInteger.ONE,  1, 0, 1),
 new BigDecimal(BigInteger.valueOf(2), 2, 0, 1),
 new BigDecimal(BigInteger.valueOf(3), 3, 0, 1),
 new BigDecimal(BigInteger.valueOf(4), 4, 0, 1),
 new BigDecimal(BigInteger.valueOf(5), 5, 0, 1),
 new BigDecimal(BigInteger.valueOf(6), 6, 0, 1),
 new BigDecimal(BigInteger.valueOf(7), 7, 0, 1),
 new BigDecimal(BigInteger.valueOf(8), 8, 0, 1),
 new BigDecimal(BigInteger.valueOf(9), 9, 0, 1),
 new BigDecimal(BigInteger.TEN,  10, 0, 2),
};
 
 
/**
 * The value 0, with a scale of 0.
 *
 * @since 1.5
 */
public static final BigDecimal ZERO = zeroThroughTen[0];

BigDecimal newZero = new BigDecimal(0.0);
System.out.println(BigDecimal.ZERO.compareTo(newZero));
 
BigDecimal stringNewZero = new BigDecimal("0.0");
System.out.println(BigDecimal.ZERO.compareTo(stringNewZero));
 
BigDecimal noScaleZero = BigDecimal.valueOf(0.0);
System.out.println(BigDecimal.ZERO.compareTo(noScaleZero));
 
BigDecimal scaleZero = BigDecimal.valueOf(0.0).setScale(1);
System.out.println(BigDecimal.ZERO.compareTo(scaleZero));