17网站一起做网店,专门做网站的app,建设企业网站的需求分析,做五金有哪些网站推广简介 请求以命令的形式包裹在对象中#xff0c;并传给调用对象。调用对象寻找可以处理该命令的对象进行执行。命令模式是一种特殊的策略模式#xff0c;体现多个策略执行的问题#xff0c;而不是选择的问题 UML图 应用场景
界面选择、键盘、按钮、事件操作都类似命令模式
…简介 请求以命令的形式包裹在对象中并传给调用对象。调用对象寻找可以处理该命令的对象进行执行。命令模式是一种特殊的策略模式体现多个策略执行的问题而不是选择的问题 UML图 应用场景
界面选择、键盘、按钮、事件操作都类似命令模式
示例 电视遥控器、电视、观看电视的人 接收者电视机
public class TVReceiver {public void on() {System.out.println(打开电视);}public void off() {System.out.println(关闭电视);}public void changeStation() {System.out.println(换台);}
}命令指令
public interface Command {void excute();
}public class OnCommand implements Command {private TVReceiver tvReceiver;public OnCommand(TVReceiver tvReceiver) {this.tvReceiver tvReceiver;}Overridepublic void excute() {System.out.println(onCommand----execute);tvReceiver.on();}
}public class OffCommand implements Command {private TVReceiver tvReceiver;public OffCommand(TVReceiver tvReceiver) {this.tvReceiver tvReceiver;}Overridepublic void excute() {System.out.println(OffCommand----execute);tvReceiver.off();}
}public class ChangeStationCommand implements Command {private TVReceiver tvReceiver;public ChangeStationCommand(TVReceiver tvReceiver) {this.tvReceiver tvReceiver;}Overridepublic void excute() {System.out.println(ChangeStationCommand----execute);tvReceiver.changeStation();}
}调用者观看者
public class Invoker {private OnCommand onCommand;private OffCommand offCommand;private ChangeStationCommand changeStationCommand;public OnCommand getOnCommand() {return onCommand;}public void setOnCommand(OnCommand onCommand) {this.onCommand onCommand;}public OffCommand getOffCommand() {return offCommand;}public void setOffCommand(OffCommand offCommand) {this.offCommand offCommand;}public ChangeStationCommand getChangeStationCommand() {return changeStationCommand;}public void setChangeStationCommand(ChangeStationCommand changeStationCommand) {this.changeStationCommand changeStationCommand;}/*** 开*/public void on() {onCommand.excute();}/*** 关*/public void off() {offCommand.excute();}/*** 换台*/public void changeStation() {changeStationCommand.excute();}
}运行
public class Main {public static void main(String[] args) {// 创建接收者物品TVReceiver tvReceiver new TVReceiver();// 创建指令遥控器OnCommand onCommand new OnCommand(tvReceiver);OffCommand offCommand new OffCommand(tvReceiver);ChangeStationCommand changeStationCommand new ChangeStationCommand(tvReceiver);// 创建使用者Invoker invoker new Invoker();invoker.setOffCommand(offCommand);invoker.setOnCommand(onCommand);invoker.setChangeStationCommand(changeStationCommand);// 使用者作出指示invoker.on();System.out.println(------------);invoker.changeStation();System.out.println(------------);invoker.off();}
}总结 优点 调用者对象与接受者对象没有任何依赖关系降低了系统的耦合度方便新的命令添加至系统中扩展性强 缺点 过多的命令会导致系统中存在过多的具体命令类
