实现简单工厂模式

比眉伴天荒 2022-06-18 01:45 151阅读 0赞

**实现简单工厂模式**

package factory.test3;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    
    import factory.test2.Operation;
    
    public class Main {
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    		String strNumA,strNumB,strOperationalSign;
    		System.out.println("Please input a number A:");
    		try {
    			strNumA=br.readLine().trim();
    			System.out.println("Please input an operational sign:");
    			strOperationalSign=br.readLine().trim();
    			factory.test3.Operation operationObject=OperationFactory.createOperation(strOperationalSign);
    			System.out.println("Please input a number B:");
    			strNumB=br.readLine().trim();
    			operationObject.setNumA(Double.parseDouble(strNumA));
    			operationObject.setNumB(Double.parseDouble(strNumB));
    			Double result=operationObject.getResult();
    			System.out.println("The result is :"+ result );
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    }

package factory.test3;
    
    public class Operation {
    	private double numA=0;
    	private double numB=0;
    	
    	
    	public double getNumA() {
    		return numA;
    	}
    
    
    	public double getNumB() {
    		return numB;
    	}
    
    
    	public void setNumA(double numA) {
    		this.numA = numA;
    	}
    
    
    	public void setNumB(double numB) {
    		this.numB = numB;
    	}
    
    
    	public double getResult(){
    		double result=0;
    		return result ;
    	}
    	
    }

package factory.test3;
    
    public class OperationAdd extends Operation{
    	public double getResult(){
    		double result=0;
    		result=getNumA()+getNumB();
    		return result;
    	}
    }

package factory.test3;
    
    public class OperationSubtract extends Operation{
    	public double getResult(){
    		double result=0;
    		result=getNumA()-getNumB();
    		return result;
    	}
    }

package factory.test3;
    
    public class OperationMultiply extends Operation{
    	public double getResult(){
    		double result=0;
    		result=getNumA()*getNumB();
    		return result;
    	}
    }

package factory.test3;
    
    public class OperationDivide extends Operation{
    	public double getResult(){
    		double result=0;
    		result=getNumA()/getNumB();
    		return result;
    	}
    }

package factory.test3;
    
    public class OperationFactory {
    	public static Operation createOperation(String strOperationalSign){
    		int intOperationalSign = 1;
    		Double strResult = null;
    		if("+".equals(strOperationalSign)){
    			intOperationalSign=1;
    		}else if("-".equals(strOperationalSign)){
    			intOperationalSign=2;
    		}else if("*".equals(strOperationalSign)){
    			intOperationalSign=3;
    		}else if("/".equals(strOperationalSign)){
    			intOperationalSign=4;
    		}
    		switch(intOperationalSign){
    			case 1:
    				return new OperationAdd();
    			case 2:
    				return new OperationSubtract();
    			case 3:
    				return new OperationMultiply();
    			case 4:
    				return new OperationDivide();
    			default:
    				return null;
    		}
    	}
    }

注：本文章所涵盖的知识来源于程杰老师的《大话设计模式》，我从中受益匪浅，推荐大家拜读：）