java BigDecimal比較大小

BigDecimal比較大小
   這個類是java裏精確計算的類，下面說一下兩個BigDecimal對象大小，相等的判斷
   1 比較對象是否相等
     一般的對象用equals，但是BigDecimal比較特殊，舉個例子：
     BigDecimal a=BigDecimal.valueOf(1.0);
     BigDecimal b=BigDecimal.valueOf(1.000);
     在現實中這兩個數字是相等的，但是問題來來了
     a.equals(b)結果是false;怎麼不相等了呢？這個問題我也不知道
     解決辦法：
            if(a.compareTo(b)==0)結果是true
     public int compareTo(BigDecimal val)
          Compares this BigDecimal with the specified BigDecimal.
         Two BigDecimal objects that are equal in value but have a different
         scale (like 2.0 and 2.00) are considered equal by this method.
         This method is provided in preference to individual methods for each of
         the six boolean comparison operators (<, ==, >, >=, !=, <=).
         The suggested idiom for performing these comparisons is: (x.compareTo(y) <op> 0), where <op> is one of the six comparison operators.

    Specified by:
    compareTo in interface Comparable<BigDecimal>
    Parameters:
    val - BigDecimal to which this BigDecimal is to be compared.
    Returns:
       -1, 0, or 1 as this BigDecimal is numerically less than, equal to, or greater than val.
    簡單翻譯：
           結果是-1 小於
                  0 等於
                  1 大於