Java中Math.round() Math.floor() Math.ceil()方法的区别

Math.rount()方法，即对传入的float或者double数据进行四舍五入操作，具体的执行过程是，先将传入的参数+0.5，然后向下取整。
Math.floor()方法，向下取整。即返回小于等于参数的最大整数
Math.ceil()方法，向上取整。即返回大于等于参数的最小整数。

public static void main(String[] args) {
    
    
        System.out.println("Math.round()方法  四舍五入");
        System.out.println("1.5  = "+Math.round(1.5));
        System.out.println("-1.5 = "+Math.round(-1.5));
        System.out.println("-1.6 = "+Math.round(-1.6));
        System.out.println("1.6  = "+Math.round(1.6));
        System.out.println("----------------");
        System.out.println("Math.floor()方法  向下取整");
        System.out.println("1.5  = "+Math.floor(1.5));
        System.out.println("-1.5 = "+Math.floor(-1.5));
        System.out.println("-1.6 = "+Math.floor(-1.6));
        System.out.println("1.6  = "+Math.floor(1.6));
        System.out.println("+----------------");
        System.out.println("Math.ceil()方法  向上取整");
        System.out.println("1.5  = "+Math.ceil(1.5));
        System.out.println("-1.5 = "+Math.ceil(-1.5));
        System.out.println("-1.6 = "+Math.ceil(-1.6));
        System.out.println("1.6  = "+Math.ceil(1.6));
    }