哪位高手能帮帮小弟我，JAVA怎么约分结果

import java.util.*;public class Rational<finalfenzi> {    private int fenzi;    private int fenmu;          public int getfenzi(){return fenzi;}    public void setfenzi(int fenzi){this.fenzi=fenzi;}    public int getfenmu(){return fenmu;}        public void setY(int fenmu){this.fenmu=fenmu; }    public Rational (int fenzi,int fenmu){           this.fenzi=fenzi;            if(fenmu==0){        System.out.print("fenmu cannot be zero!");                }                 this.fenmu=fenmu;             }            public String toString()        {         return ""+fenzi+"/"+fenmu;     }        public Rational common(int finalfenzi, int finalfenmu) {            Rational rational = new Rational(finalfenzi,finalfenmu);            if(finalfenmu < 0 && finalfenzi > 0 || finalfenmu < 0 && finalfenzi < 0)            rational = new Rational(-finalfenzi,-finalfenmu);            return rational;  //结果正负号；            }        public Rational add(Rational a){            int finalfenmu=this.fenmu*a.getfenmu();                int finalfenzi=this.fenzi*a.getfenmu()+a.getfenzi()*this.fenmu;                                                    return common(finalfenzi,finalfenmu);   //加法；             }       public Rational subtract(Rational a){             int finalfenmu=this.fenmu*a.getfenmu();           int finalfenzi=this.fenzi*a.getfenmu()-a.getfenzi()*this.fenmu;               return common(finalfenzi,finalfenmu);    //减法；    }         public Rational multiply(Rational a){             int finalfenmu=this.fenmu*a.getfenmu();                int finalfenzi=this.fenzi*a.getfenzi();                    return common(finalfenzi,finalfenmu);    //乘法；     }       public Rational divide(Rational a){            int finalfenmu=this.fenmu*a.getfenzi();                int finalfenzi=this.fenzi*a.getfenmu();                    return common(finalfenzi,finalfenmu);    //除法；            }                      public static void main(String[] args) {             Scanner in=new Scanner(System.in);           System.out.print("Enter the first fenzi=");              int a = in.nextInt();           System.out.print("Enter the first fenmu=");           int b = in.nextInt();               System.out.print("Enter the second fenzi=");           int c = in.nextInt();           System.out.print("Enter the second fenmu=");           int d = in.nextInt();        Rational s=new Rational(a,b);            Rational s1=new Rational(c,d);                            Rational s2=s.add(s1);                System.out.println(s+"+"+s1+"="+s2);                    Rational s3=s.subtract(s1);        System.out.println(s+"-"+s1+"="+s3);                    Rational s4=s.multiply(s1);                System.out.println(s+"*"+s1+"="+s4);                    Rational s5=s.divide(s1);            System.out.println(s+"/"+s1+"="+s5);        }}

public Rational reduce(){    int fz = Math.abs(this.fenzi); //取分子分母的绝对值    int fm = Math.abs(this.fenmu);    int mod = fz%fm;    while (mod > 0) { //求分子分母的最大公因数        fz = fm;        fm = mod;        mod = fz%fm;    }    return common(this.fenzi/fm, this.fenmu/fm); //分子分母都除以最大公因数}