BigDecimal.valueOf()

BigDecimal 类包含常用数字的内部缓存，例如 0 到 10. BigDecimal.valueOf() 方法优先于具有类似类型参数的构造函数提供，即在下面的示例中，a 优先于 b。

BigDecimal a = BigDecimal.valueOf(10L); //Returns cached Object reference
BigDecimal b = new BigDecimal(10L); //Does not return cached Object reference

BigDecimal a = BigDecimal.valueOf(20L); //Does not return cached Object reference
BigDecimal b = new BigDecimal(20L); //Does not return cached Object reference

BigDecimal a = BigDecimal.valueOf(15.15); //Preferred way to convert a double (or float) into a BigDecimal, as the value returned is equal to that resulting from constructing a BigDecimal from the result of using Double.toString(double)
BigDecimal b = new BigDecimal(15.15); //Return unpredictable result