简单工厂模式

public class Factory {

	/**
	 * @param args简单 工厂模式
	 */
	public static Operation creat(String o) {
		Operation operation=null;
		if (o=="+") {
			operation=new operationAdd();
		}
		return operation;
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
	Operation operation=Factory.creat("+");
	operation.setA(2);
	operation.setB(3);
	double res=operation.getresult();
	System.out.println(res);
	}
}
class Operation {
	
	private double a=0;
	private double b=0;
	
	public double getresult() {
		
		double result=0;
		return result;

	}

	public double getA() {
		return a;
	}

	public void setA(double a) {
		this.a = a;
	}

	public double getB() {
		return b;
	}

	public void setB(double b) {
		this.b = b;
	}

}


class operationAdd extends Operation{
	
	public double getresult() {
		double result=0;
		result=getA()+getB();
		return result;
		
	}
	
	
}