public class Invoker {
    //执行的命令
    private Command command;
    public Invoker(Command command){
        this.command = command;
    }
    public void execute(){
        this.command.excute();
    }
}

public abstract class Command {
    //抽象的执行方法
    public abstract void excute();
}

public class ConcreteCommand1 extends Command{
    //具体的命令的接收者
    private Receiver receiver;
    public ConcreteCommand1(){
        this.receiver = new Receiver1();
    }
    public ConcreteCommand1(Receiver receiver){
        this.receiver = receiver;
    }
    @Override
    public void excute() {
        // TODO Auto-generated method stub
        this.receiver.doSomething();
    }
}

public abstract class Receiver {
    //执行者的抽象执行方法
    public abstract void doSomething();
}

public class Receiver1 extends Receiver{
    @Override
    public void doSomething() {
        // TODO Auto-generated method stub
        System.out.println("receiver1 do something");
    }
}

public class Client {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Command command = new ConcreteCommand1();
        Invoker invoker = new Invoker(command);
        invoker.execute();
    }
}