抽象工厂类--一个简单的例子

package com.hbc.factory;

public abstract class Cal {
    public abstract int getResult(int a, int b);
}

package com.hbc.factory;

public class Add extends Cal{

    @Override
    public int getResult(int a, int b) {
        return a + b;
    }

}

package com.hbc.factory;

public class Sub extends Cal{

    @Override
    public int getResult(int a, int b) {
        return a - b;
    }

}

package com.hbc.factory;

public class Mul extends Cal{

    @Override
    public int getResult(int a, int b) {
        return a * b;
    }

}

package com.hbc.factory;

public class Div extends Cal{

    @Override
    public int getResult(int a, int b) {
        return a / b;
    }

}

package com.hbc.factory;

import java.util.Scanner;

public class Operation{
    public static Cal getCal(char c){
        Cal cal = null;
        switch(c){
            case ‘+‘:
                cal = new Add();
                break;
            case ‘-‘:
                cal = new Sub();
                break;
            case ‘*‘:
                cal = new Mul();
                break;
            case ‘/‘:
                cal = new Div();
                break;
            default:
                System.out.println("不好意思，您输入的操作有误");
        }
        return cal;
    }
    public static void main(String[] args) {
        System.out.println("请输入您要进行的操作");
        Scanner cin = new Scanner(System.in);
        while(cin.hasNext()){
            
            String op = cin.next();
            Cal cal = getCal(op.charAt(0));
            System.out.println("请输入您要操作的数字");
            int a = cin.nextInt();
            int b = cin.nextInt();
            System.out.println("计算的结果是： " + cal.getResult(a, b));
            System.out.println("请输入您要进行的操作");
        }
        
    }
}