java中的截取和舍入

public class CastingNumbers {
    public static void main(String[] args){
        double above =0.7,below=0.4;
        float fabove=0.7f,fbelow=0.4f;
        System.out.println("(int)above:"+(int)above);
        System.out.println("(int)below:"+(int)below);
        System.out.println("(int)fabove:"+(int)fabove);
        System.out.println("(int)fbelow:"+(int)fbelow);

        System.out.println("Math.round(above):"+Math.round(above));
        System.out.println("Math.round(below):"+Math.round(below));
        System.out.println("Math.round(fabove):"+Math.round(fabove));
        System.out.println("Math.round(fbelow):"+Math.round(fbelow));
    }

}

OUT:

(int)above:0
(int)below:0
(int)fabove:0
(int)fbelow:0
Math.round(above):1
Math.round(below):0
Math.round(fabove):1
Math.round(fbelow):0

 

PS:在将float或double转型为整型值时，总是对该数字执行截尾。如果想要得到舍入得结果，就需要使用java.lang.Math中的round()方法。