定义：将一个请求封装成一个对象，从而让你使用不同的请求把客户端参数化，对请求排队或者记录请求日志，可
以提供命令的撤销和恢复功能。
package command; public class Receiver { public void doSomething(){ System.out.println("接收者执行业务逻辑处理"); } } package command; public interface Command { void execute(); } package command; public class ConcreteCommand implements Command { Receiver receiver; public ConcreteCommand(Receiver receiver) { this.receiver=receiver; } @Override public void execute() { // TODO Auto-generated method stub receiver.doSomething(); } } package command; public class Invoker { private Command command; public void setCommand(Command command) { this.command = command; } public void action(){ this.command.execute(); } } package command; public class Client { public static void main(String[] args){ Receiver receiver = new Receiver(); Command command = new ConcreteCommand(receiver); //客户端直接执行具体命令方式 command.execute(); //客户端通过调用者来执行命令 Invoker invoker = new Invoker(); invoker.setCommand(command); invoker.action(); } } 命令模式优缺点：
命令模式适用场景：
该不该引入设计模式：
