命令模式-接收者与执行者解耦和
老板：阿飞，咱们公司又接了个新项目，一个客户，，卧室和客厅很大，电灯电视开关也不好找，所以希望制造一个遥控器来控制一些家具的开启与关闭，目前需要5个按键，卧室的灯，卧室的电视，客厅的灯，客厅的电视，在留一个预备按键。我等会把需求文档给你。 项目组长阿飞：好的，老板 项目组长阿飞：小三，来了个需求，你看下，你先设计一下架构 阿三：好的，飞哥
三天过后：飞哥，好了，你看下
先设计了一个接口，里面包含了，每一个按钮的统一行为
1package com.commandPattern.command;
2
3/**
4 * @program: testPattern
5 * @description: 命令接口
6 * @author: Mr.Yang
7 * @create: 2018-12-08 13:54
8 **/
9public interface Command {
10
11 //执行方法
12 public void exceute();
13
14}然后建立了一个对象，代表了空对象，什么操作也不执行
1package com.commandPattern.command.nullCommand;
2
3import com.commandPattern.command.Command;
4
5/**
6 * @program: testPattern
7 * @description: 建立一个空对象，在许多设计模式种，都会看到空对象的使用，甚至有些时候，空对象本身也被视为一种设计模式
8 * @author: Mr.Yang
9 * @create: 2018-12-08 17:40
10 **/
11public class NullCommand implements Command {
12 public void exceute() {
13 System.out.println("什么都不做处理");
14 }
15}灯的具体类
1package com.commandPattern.entity;
2
3/**
4 * @program: testPattern
5 * @description: 灯的具体类
6 * @author: Mr.Yang
7 * @create: 2018-12-08 17:31
8 **/
9public class Lamp {
10 private String name;
11
12 /**
13 * name为灯的具体装饰，即为哪里的灯
14 * @param name
15 */
16 public Lamp(String name){
17 this.name=name;
18 }
19 public void on (){
20 System.out.println(name+"_灯打开");
21 }
22 public void off (){
23 System.out.println(name+"_灯关闭");
24 }
25}电视的具体类
1package com.commandPattern.entity;
2
3/**
4 * @program: testPattern
5 * @description: 电视的具体类
6 * @author: Mr.Yang
7 * @create: 2018-12-08 17:35
8 **/
9public class Tv {
10 private String name;
11 public Tv(String name){
12 this.name=name;
13 }
14 public void on (){
15 System.out.println(name+"_电视打开");
16 }
17 public void off(){
18 System.out.println(name+"_电视关闭");
19 }
20}关闭灯的具体命令
1package com.commandPattern.command.off;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Lamp;
5
6/**
7 * @program: testPattern
8 * @description: 灯关闭
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:33
11 **/
12public class LampOffCommand implements Command {
13
14 Lamp lamp;
15
16 public LampOffCommand(Lamp lamp){
17 this.lamp=lamp;
18 }
19 //灯关闭
20 public void exceute() {
21 lamp.off();
22 }
23}打开灯的具体命令
1package com.commandPattern.command.on;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Lamp;
5
6/**
7 * @program: testPattern
8 * @description: 灯打开的命令
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:29
11 **/
12public class LampOnCommand implements Command {
13
14 Lamp lamp;
15 public LampOnCommand(Lamp lamp){
16 this.lamp=lamp;
17 }
18
19 //灯打开的命令
20 public void exceute() {
21 lamp.on();
22 }
23}电视关闭的具体命令
1package com.commandPattern.command.off;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Tv;
5
6/**
7 * @program: testPattern
8 * @description: 电视关闭
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:36
11 **/
12public class TvOffCommand implements Command {
13 Tv tv;
14 public TvOffCommand(Tv tv){
15 this.tv=tv;
16 }
17 public void exceute() {
18 tv.off();
19 }
20}电视打开的具体命令
1package com.commandPattern.command.on;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Tv;
5
6/**
7 * @program: testPattern
8 * @description: 电视打开
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:37
11 **/
12public class TvOnCommand implements Command {
13 Tv tv;
14 public TvOnCommand(Tv tv){
15 this.tv=tv;
16 }
17
18 public void exceute() {
19 tv.on();
20 }
21}建立一个遥控器
1package com.commandPattern.control;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.command.nullCommand.NullCommand;
5
6import java.util.Arrays;
7
8/**
9 * @program: testPattern
10 * @description: 遥控器
11 * @author: Mr.Yang
12 * @create: 2018-12-08 17:39
13 **/
14public class RemoteControl {
15
16 Command[] onCommand;
17 Command[] offCommand;
18
19 //初始化每个操作为空操作
20 public RemoteControl(){
21 onCommand=new Command[5];
22 offCommand=new Command[5];
23 NullCommand nullCommand = new NullCommand();
24 for (int i = 0; i < 5; i++) {
25 onCommand[i]=nullCommand;
26 offCommand[i]=nullCommand;
27 }
28 }
29
30 public void setCommond(int index,Command onCommand,Command offCommand){
31 this.offCommand[index]=offCommand;
32 this.onCommand[index]=onCommand;
33 }
34
35 public void clickOn(int index){
36 onCommand[index].exceute();
37 }
38
39 public void clickOff(int index){
40 offCommand[index].exceute();
41 }
42
43 /**
44 * 输出每个按钮的具体代表类
45 * @return
46 */
47 @Override
48 public String toString() {
49 StringBuffer sb = new StringBuffer();
50 for (int i = 0; i < onCommand.length; i++) {
51 sb.append("[index : "+i+"] ");
52 sb.append(onCommand[i].getClass().getName());
53 sb.append(" ");
54 sb.append(offCommand[i].getClass().getName());
55 sb.append("\r\n");
56 }
57 return sb.toString();
58 }
59}测试类
1package com.commandPattern.testPattern;
2
3import com.commandPattern.command.off.LampOffCommand;
4import com.commandPattern.command.off.TvOffCommand;
5import com.commandPattern.command.on.LampOnCommand;
6import com.commandPattern.command.on.TvOnCommand;
7import com.commandPattern.control.RemoteControl;
8import com.commandPattern.entity.Lamp;
9import com.commandPattern.entity.Tv;
10
11/**
12 * @program: test
13 * @description:
14 * @author: Mr.Yang
15 * @create: 2018-12-08 17:48
16 **/
17public class TestPattern {
18 public static void main(String[] args) {
19 RemoteControl remoteControl = new RemoteControl();
20
21 /**
22 * 创建装置到合适位置
23 */
24 Tv bedRoomTV = new Tv("卧室");
25 Tv drawiTV = new Tv("客厅");
26
27 Lamp bedRoomLamp = new Lamp("卧室");
28 Lamp drawiLamp = new Lamp("客厅");
29
30 /**
31 * 创建所有命令操作对象
32 */
33 //卧室灯关闭对象
34 LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
35 //卧室灯打开对象
36 LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
37 //卧室TV关闭对象
38 TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
39 //卧室TV打开对象
40 TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
41 //客厅灯打开对象
42 LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
43 //客厅灯关闭对象
44 LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
45 //客厅TV关闭对象
46 TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
47 //客厅TV打开对象
48 TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);
49
50 System.out.println("---------------------------------------------未赋值之前------------------------------------------------");
51 System.out.println(remoteControl);
52 System.out.println("******************************************************************************************************");
53
54 /**
55 * //将操作对象与卡槽一一对应
56 */
57 //赋值卧室灯打开与关闭
58 remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
59 //赋值卧室TV打开与关闭
60 remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
61 //赋值客厅灯打开与关闭
62 remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
63 //赋值客厅TV打开与关闭
64 remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);
65
66 System.out.println("---------------------------------------------赋值之后------------------------------------------------");
67 System.out.println(remoteControl);
68 System.out.println("******************************************************************************************************");
69
70
71 /**
72 * 测试每一个按钮
73 */
74 remoteControl.clickOn(0);
75 remoteControl.clickOff(0);
76
77 remoteControl.clickOn(1);
78 remoteControl.clickOff(1);
79
80 remoteControl.clickOn(2);
81 remoteControl.clickOff(2);
82
83 remoteControl.clickOn(3);
84 remoteControl.clickOff(3);
85
86
87 }
88}测试结果
1---------------------------------------------未赋值之前------------------------------------------------
2[index : 0] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
3[index : 1] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
4[index : 2] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
5[index : 3] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
6[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
7
8******************************************************************************************************
9---------------------------------------------赋值之后------------------------------------------------
10[index : 0] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
11[index : 1] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
12[index : 2] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
13[index : 3] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
14[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
15
16******************************************************************************************************
17卧室_灯打开
18卧室_灯关闭
19卧室_电视打开
20卧室_电视关闭
21客厅_灯打开
22客厅_灯关闭
23客厅_电视打开
24客厅_电视关闭阿三：飞哥，我这里使用的设计模式-命令模式， 将动作执行（LampOnCommand，TvOnCommand……）与接收者（Lamp，Tv）包装到对象里面，对外暴露的只有一个Command接口中的execute方法，其他对象不需要知道那个接收者执行了什么动作，只需要知道调用execute，就能完成一个请求的操作，这个对象，与其他对象没有关联，完全解耦和，如果需要做新增，不需要修改原有代码，拓展接收者类和动作执行类，就能实现功能。
项目组长阿飞：不错，不错，进步很大。 项目组长阿飞：第5个按钮可能需要做一个恢复上一步动作的效果，类似于CTRL+Z这个效果，你再改改把。 阿三：好的。 阿三：飞哥修改好了，你看下
命令接口新增撤销方法
1package com.commandPattern.command;
2
3/**
4 * @program: testPattern
5 * @description: 命令接口
6 * @author: Mr.Yang
7 * @create: 2018-12-08 13:54
8 **/
9public interface Command {
10
11 //执行方法
12 public void exceute();
13
14 //撤销方法
15 public void revoke();
16
17}建立一个空对象,实现了撤销方法
1package com.commandPattern.command.nullCommand;
2
3import com.commandPattern.command.Command;
4
5/**
6 * @program: testPattern
7 * @description: 建立一个空对象，在许多设计模式种，都会看到空对象的使用，甚至有些时候，空对象本身也被视为一种设计模式
8 * @author: Mr.Yang
9 * @create: 2018-12-08 17:40
10 **/
11public class NullCommand implements Command {
12 public void exceute() {
13 System.out.println("什么都不做处理");
14 }
15
16 public void revoke() {
17 System.out.println("什么都不做处理");
18 }
19}灯关闭实现了撤销方法
1package com.commandPattern.command.off;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Lamp;
5
6/**
7 * @program: testPattern
8 * @description: 灯关闭
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:33
11 **/
12public class LampOffCommand implements Command {
13
14 Lamp lamp;
15
16 public LampOffCommand(Lamp lamp){
17 this.lamp=lamp;
18 }
19 //灯关闭
20 public void exceute() {
21 lamp.off();
22 }
23 //执行到这个具体实现类，代表上一步是灯关闭，撤销操作即为灯打开
24 public void revoke() {
25 lamp.on();
26 }
27}灯打开实现了撤销方法
1package com.commandPattern.command.on;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Lamp;
5
6/**
7 * @program: testPattern
8 * @description: 灯打开的命令
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:29
11 **/
12public class LampOnCommand implements Command {
13
14 Lamp lamp;
15 public LampOnCommand(Lamp lamp){
16 this.lamp=lamp;
17 }
18
19 //灯打开的命令
20 public void exceute() {
21 lamp.on();
22 }
23 //执行到这个具体实现类，代表上一步是灯打开，撤销操作即为灯关闭
24 public void revoke() {
25 lamp.off();
26 }
27}电视关闭实现了撤销方法
1package com.commandPattern.command.off;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Tv;
5
6/**
7 * @program: testPattern
8 * @description: 电视关闭
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:36
11 **/
12public class TvOffCommand implements Command {
13 Tv tv;
14 public TvOffCommand(Tv tv){
15 this.tv=tv;
16 }
17 public void exceute() {
18 tv.off();
19 }
20 //执行到这个具体实现类，代表上一步是电视关闭，撤销操作即为电视打开
21 public void revoke() {
22 tv.on();
23 }
24}电视打开实现了撤销方法
1package com.commandPattern.command.on;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.entity.Tv;
5
6/**
7 * @program: testPattern
8 * @description: 电视打开
9 * @author: Mr.Yang
10 * @create: 2018-12-08 17:37
11 **/
12public class TvOnCommand implements Command {
13 Tv tv;
14 public TvOnCommand(Tv tv){
15 this.tv=tv;
16 }
17
18 public void exceute() {
19 tv.on();
20 }
21 //执行到这个具体实现类，代表上一步是电视打开，撤销操作即为电视关闭
22 public void revoke() {
23 tv.off();
24 }
25}遥控器类，新增变量记录上一步操作
1package com.commandPattern.control;
2
3import com.commandPattern.command.Command;
4import com.commandPattern.command.nullCommand.NullCommand;
5
6import java.util.Arrays;
7
8/**
9 * @program: testPattern
10 * @description: 遥控器
11 * @author: Mr.Yang
12 * @create: 2018-12-08 17:39
13 **/
14public class RemoteControl {
15
16 Command[] onCommand;
17 Command[] offCommand;
18 //这个变量来记录上一个命令
19 Command upStepCommand;
20 //初始化每个操作为空操作
21 public RemoteControl(){
22 onCommand=new Command[5];
23 offCommand=new Command[5];
24 NullCommand nullCommand = new NullCommand();
25 for (int i = 0; i < 5; i++) {
26 onCommand[i]=nullCommand;
27 offCommand[i]=nullCommand;
28 }
29 upStepCommand=nullCommand;
30 }
31
32 public void setCommond(int index,Command onCommand,Command offCommand){
33 this.offCommand[index]=offCommand;
34 this.onCommand[index]=onCommand;
35 }
36 //新增upStepCommand记录上一步命令
37 public void clickOn(int index){
38 onCommand[index].exceute();
39 upStepCommand=onCommand[index];
40 }
41 //新增upStepCommand记录上一步命令
42 public void clickOff(int index){
43 offCommand[index].exceute();
44 upStepCommand=offCommand[index];
45 }
46
47 public void toUpStepClick(){
48 System.out.println("---撤销---");
49 upStepCommand.revoke();
50 }
51 /**
52 * 输出每个按钮的具体代表类
53 * @return
54 */
55 @Override
56 public String toString() {
57 StringBuffer sb = new StringBuffer();
58 for (int i = 0; i < onCommand.length; i++) {
59 sb.append("[index : "+i+"] ");
60 sb.append(onCommand[i].getClass().getName());
61 sb.append(" ");
62 sb.append(offCommand[i].getClass().getName());
63 sb.append("\r\n");
64 }
65 return sb.toString();
66 }
67}测试类新增撤销测试
1package com.commandPattern.testPattern;
2
3import com.commandPattern.command.off.LampOffCommand;
4import com.commandPattern.command.off.TvOffCommand;
5import com.commandPattern.command.on.LampOnCommand;
6import com.commandPattern.command.on.TvOnCommand;
7import com.commandPattern.control.RemoteControl;
8import com.commandPattern.entity.Lamp;
9import com.commandPattern.entity.Tv;
10
11/**
12 * @program: test
13 * @description:
14 * @author: Mr.Yang
15 * @create: 2018-12-08 17:48
16 **/
17public class TestPattern {
18 public static void main(String[] args) {
19 RemoteControl remoteControl = new RemoteControl();
20
21 /**
22 * 创建装置到合适位置
23 */
24 Tv bedRoomTV = new Tv("卧室");
25 Tv drawiTV = new Tv("客厅");
26
27 Lamp bedRoomLamp = new Lamp("卧室");
28 Lamp drawiLamp = new Lamp("客厅");
29
30 /**
31 * 创建所有命令操作对象
32 */
33 //卧室灯关闭对象
34 LampOffCommand bedLampOffCommand = new LampOffCommand(bedRoomLamp);
35 //卧室灯打开对象
36 LampOnCommand bedLampOnCommand = new LampOnCommand(bedRoomLamp);
37 //卧室TV关闭对象
38 TvOffCommand bedTvOffCommand = new TvOffCommand(bedRoomTV);
39 //卧室TV打开对象
40 TvOnCommand bedTVcommand = new TvOnCommand(bedRoomTV);
41 //客厅灯打开对象
42 LampOnCommand drawLampOnCommand = new LampOnCommand(drawiLamp);
43 //客厅灯关闭对象
44 LampOffCommand drawLampOffCommand = new LampOffCommand(drawiLamp);
45 //客厅TV关闭对象
46 TvOffCommand drawTVOffCommand = new TvOffCommand(drawiTV);
47 //客厅TV打开对象
48 TvOnCommand drawTVOnCommand = new TvOnCommand(drawiTV);
49
50 System.out.println("---------------------------------------------未赋值之前------------------------------------------------");
51 System.out.println(remoteControl);
52 System.out.println("******************************************************************************************************");
53
54 /**
55 * //将操作对象与卡槽一一对应
56 */
57 //赋值卧室灯打开与关闭
58 remoteControl.setCommond(0,bedLampOnCommand,bedLampOffCommand);
59 //赋值卧室TV打开与关闭
60 remoteControl.setCommond(1,bedTVcommand,bedTvOffCommand);
61 //赋值客厅灯打开与关闭
62 remoteControl.setCommond(2,drawLampOnCommand,drawLampOffCommand);
63 //赋值客厅TV打开与关闭
64 remoteControl.setCommond(3,drawTVOnCommand,drawTVOffCommand);
65
66 System.out.println("---------------------------------------------赋值之后------------------------------------------------");
67 System.out.println(remoteControl);
68 System.out.println("******************************************************************************************************");
69
70
71 /**
72 * 测试每一个按钮
73 */
74 remoteControl.clickOn(0);
75 remoteControl.clickOff(0);
76
77 //撤销一次
78 remoteControl.toUpStepClick();
79 System.out.println("\r\n");
80
81 //撤销一次
82 remoteControl.toUpStepClick();
83 System.out.println("\r\n");
84
85 remoteControl.clickOn(1);
86 remoteControl.clickOff(1);
87
88 //撤销一次
89 remoteControl.toUpStepClick();
90 System.out.println("\r\n");
91
92 remoteControl.clickOn(2);
93 remoteControl.clickOff(2);
94
95 //撤销一次
96 remoteControl.toUpStepClick();
97 System.out.println("\r\n");
98
99 remoteControl.clickOn(3);
100 remoteControl.clickOff(3);
101
102 //撤销一次
103 remoteControl.toUpStepClick();
104 System.out.println("\r\n");
105
106 }
107}修改之后的测试结果
1---------------------------------------------未赋值之前------------------------------------------------
2[index : 0] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
3[index : 1] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
4[index : 2] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
5[index : 3] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
6[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
7
8******************************************************************************************************
9---------------------------------------------赋值之后------------------------------------------------
10[index : 0] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
11[index : 1] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
12[index : 2] com.commandPattern.command.on.LampOnCommand com.commandPattern.command.off.LampOffCommand
13[index : 3] com.commandPattern.command.on.TvOnCommand com.commandPattern.command.off.TvOffCommand
14[index : 4] com.commandPattern.command.nullCommand.NullCommand com.commandPattern.command.nullCommand.NullCommand
15
16******************************************************************************************************
17卧室_灯打开
18卧室_灯关闭
19---撤销---
20卧室_灯打开
21
22
23---撤销---
24卧室_灯打开
25
26
27卧室_电视打开
28卧室_电视关闭
29---撤销---
30卧室_电视打开
31
32
33客厅_灯打开
34客厅_灯关闭
35---撤销---
36客厅_灯打开
37
38
39客厅_电视打开
40客厅_电视关闭
41---撤销---
42客厅_电视打开项目组长阿飞：不错，不错，以后给你涨工资。
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原始发表：2018-12-08，如有侵权请联系 cloudcommunity@tencent.com 删除
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