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