java 向上或向下取整Math

向上取整用Math.ceil(double a)

向下取整用Math.floor(double a)

举例：

double a=35;

double b=20;

double c = a/b;

System.out.println("c===>"+c); //1.75

System.out.println("c===>"+Math.ceil(c)); //2.0

System.out.println(Math.floor(c)); //1.0

注意

int a=25；

int b=20;

int c=a/b //结果是1

int c=（double）a/b //结果是1.25

System.out.println("c===>"+Math.ceil(c)); //2.0

参考：http://dilegencehe.blog.163.com/blog/static/43255413201111178523181/