简单工厂模式

工厂类生产output实例

public class OutputFactory {
	public Output getOutput(){
		return new Printer();
	}
}

Computer类，可以利用工厂得到output实例

public class Computer {
	private Output out;
	public Computer(Output out){
		this.out = out;
	}
	public void keyIn(String msg){
		out.getData(msg);
	}
	public void print(){
		out.out();
	}
	public static void main(String args[]){
		OutputFactory of = new OutputFactory();
		Computer computer = new Computer(of.getOutput());
		computer.keyIn("output success");
		computer.print();
	}
}

Output规范接口

public interface Output {
	public void out();
	public void getData(String msg);
}

Output实现类

public class Printer implements Output{
	String msg;
	public void out() {
		System.out.println("the output: " + msg);
	}
	public void getData(String msg) {
		 this.msg = msg;
	}
}