萌新求助，为什么public class DivisionTest报错啊

Question

class Division{
    private int dividend=1;
    private int divisor=1;
    public int getDividend(){
        return dividend;
    }
    public void setDividend(int a){
        dividend=a;
    }
    public int getDivisor(){
        return divisor;
    }
    public void setDivisor(int b){
        if(b==0){
            System.out.println("除数不能为0！");
        }else {
            divisor=b;
        }
    }
    public void display(){
        System.out.println(dividend/divisor);
    }

}

public class DivisionTest {
    public static void main(String[] args) {
        Division division=new Division();
        division.setDividend(10);
        division.setDivisor(2);
        division.display();
    }
}

Answer 1

因为.java文件名称是以 public class name 的name来命名,如果是多个就无法确定以哪个命名

具体应该说一个.java类中,只能有一个public修饰的class 类(最外层,除内部类),内部类就可以有多个public修饰的class如下所示

public class DivisionTest {
    public class Division {
        private int dividend = 1;
        private int divisor = 1;

        public int getDividend() {
            return dividend;
        }

        public void setDividend(int a) {
            dividend = a;
        }

        public int getDivisor() {
            return divisor;
        }

        public void setDivisor(int b) {
            if (b == 0) {
                System.out.println("除数不能为0！");
            } else {
                divisor = b;
            }
        }

        public void display() {
            System.out.println(dividend / divisor);
        }

    }
}

 class TT {
    public static void main(String[] args) {
        DivisionTest divisionTest = new DivisionTest();
        DivisionTest.Division division = divisionTest.new Division();
        division.setDividend(10);
        division.setDivisor(2);
        division.display();
    }
}