public Polar setCenter(Object[] center)
    {
        if (center.length != 2 || !center[0].getClass().getName().equals(center[1].getClass().getName()))
            throw new IllegalArgumentException("center参数的形式：[String,String]或[int,int]");
        else if (center[0] instanceof String || center[0] instanceof Number)
            this.center = center;
        else
            throw new IllegalArgumentException("center参数的形式：[String,String]或[int,int]");
        return this;
    }