Java實現(xiàn)狀態(tài)模式的示例代碼

更新時間：2025年02月11日 08:23:36 作者：new666999

狀態(tài)模式是一種行為型設計模式,允許對象根據(jù)其內(nèi)部狀態(tài)改變行為,本文主要介紹了Java實現(xiàn)狀態(tài)模式的示例代碼,文中通過示例代碼介紹的非常詳細,需要的朋友們下面隨著小編來一起學習學習吧

一、簡介

1、定義

狀態(tài)模式 (State Pattern)是一種行為型設計模式，允許對象在內(nèi)部狀態(tài)改變時改變它的行為。通過定義狀態(tài)接口和具體狀態(tài)類，將對象的狀態(tài)和行為分開，使得狀態(tài)改變時可以改變行為。

2、狀態(tài)模式的結(jié)構(gòu)

狀態(tài)模式涉及以下幾個角色：
State（狀態(tài)接口）：定義了狀態(tài)類的共同接口，所有具體的狀態(tài)類都實現(xiàn)這個接口。
ConcreteState（具體狀態(tài)類）：每個具體的狀態(tài)類實現(xiàn)了State接口，并定義了在該狀態(tài)下的具體行為。
Context（上下文）：上下文類維護一個當前狀態(tài)的引用，它通常會委托給具體的狀態(tài)類來執(zhí)行相應的狀態(tài)切換。

二、Java實現(xiàn)案例

1、電燈開關狀態(tài)案例

/**
 * @Description: 狀態(tài)接口
 * @Date: 2025-02-07 17:09
 * @Author: gaoyufei
 **/
public interface State {
    void handle(Switch context);
}

/**
 * @Description: 關燈狀態(tài)
 * @Date: 2025-02-07 17:12
 * @Author: gaoyufei
 **/
public class CloseState implements State{
    @Override
    public void handle(Switch switcher) {
        switcher.setState(new OpenState());
        System.out.println("開燈了");
    }
}
/**
 * @Description: 開燈狀態(tài)
 * @Date: 2025-02-07 17:11
 * @Author: gaoyufei
 **/
public class OpenState implements State{
    @Override
    public void handle(Switch switcher) {
        switcher.setState(new CloseState());
        System.out.println("關燈了");
    }
}
/**
 * @Description: 開關，持有燈的狀態(tài)
 * @Date: 2025-02-07 17:08
 * @Author: gaoyufei
 **/
public class Switch {
    private State state;
    public Switch(State state){
        this.state=state;
    }
    public void setState(State state){
        this.state=state;
    }
    public void press(){
        state.handle(this);
    }
}

/**
 * @Description: 操作人
 * @Date: 2025-02-07 17:14
 * @Author: gaoyufei
 **/
public class Operator {
    public static void main(String[] args) throws InterruptedException {
        Switch switcher=new Switch(new CloseState());//初始狀態(tài)是關燈
        //模擬每隔1秒按壓一下開關
        while (true){
            Thread.sleep(1000);
            switcher.press();
        }
    }
}

2、番茄工作法狀態(tài)案例

/**
 * @Description: 番茄狀態(tài)接口
 * @Date: 2025-02-08 10:49
 * @Author: gaoyufei
 **/
public interface TomatoState {
    void deal(Worker worker);
}

/**
 * @Description: 番茄-工作狀態(tài)類
 * @Date: 2025-02-08 10:51
 * @Author: gaoyufei
 **/
public class WorkTomatoState implements TomatoState {
    @Override
    public void deal(Worker worker) {
        System.out.println("休息結(jié)束了，開始工作吧");
        try {
            Thread.sleep(25*60*1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("工作了25分鐘");
        worker.setTomatoState(new RestTomatoState());
    }
}

/**
 * @Description: 番茄-休息狀態(tài)類
 * @Date: 2025-02-08 10:53
 * @Author: gaoyufei
 **/
public class RestTomatoState implements TomatoState{
    @Override
    public void deal(Worker worker) {
        System.out.println("工作結(jié)束了，好好休息吧");
        try {
            Thread.sleep(5*60*1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("休息了5分鐘");
        worker.setTomatoState(new WorkTomatoState());
    }
}

/**
 * @Description: 工作者
 * @Date: 2025-02-08 10:51
 * @Author: gaoyufei
 **/
public class Worker {
    private TomatoState tomatoState;
    public Worker(TomatoState tomatoState){
        this.tomatoState=tomatoState;
    }
    public void setTomatoState(TomatoState tomatoState){
        this.tomatoState=tomatoState;
    }
    public void startTomatoClock(){
        this.tomatoState.deal(this);
    }
}

/**
 * @Description: 客戶端
 * @Date: 2025-02-08 11:02
 * @Author: gaoyufei
 **/
public class Client {
    public static void main(String[] args) {
        Worker worker=new Worker(new WorkTomatoState());
        while (true){
            worker.startTomatoClock();
        }
    }
}

3、電梯狀態(tài)案例

這是一個簡單的電梯系統(tǒng)。電梯的狀態(tài)有關門、開門、上升、下降、停止。每個狀態(tài)下電梯的行為不同。通過狀態(tài)模式，根據(jù)電梯的不同狀態(tài)執(zhí)行不同的行為。

/**
 * @Description: 電梯狀態(tài)接口
 * @Date: 2025-02-08 9:02
 * @Author: gaoyufei
 **/
public interface ElevatorState {
    void openDoor();
    void closeDoor();
    void moveUp();
    void moveDown();
    void stop();
}
/**
 * @Description: 關門狀態(tài)
 * @Date: 2025-02-08 9:05
 * @Author: gaoyufei
 **/
public class CloseState implements ElevatorState {
    private Elevator elevator;
    public CloseState(Elevator elevator){
        this.elevator=elevator;
    }
    @Override
    public void openDoor() {
        System.out.println("電梯門開了");
        elevator.setCurrentState(elevator.getOpenState());
    }
    @Override
    public void closeDoor() {
        System.out.println("電梯門已經(jīng)關了");
    }
    @Override
    public void moveUp() {
        System.out.println("電梯上升");
        elevator.setCurrentState(elevator.getMovingUpState());
    }
    @Override
    public void moveDown() {
        System.out.println("電梯下降");
        elevator.setCurrentState(elevator.getMovingDownState());
    }
    @Override
    public void stop() {
        System.out.println("電梯停止");
        elevator.setCurrentState(elevator.getStopState());
    }
}

/**
 * @Description: 開門狀態(tài)
 * @Date: 2025-02-08 9:07
 * @Author: gaoyufei
 **/
public class OpenState implements ElevatorState{
    private Elevator elevator;
    public OpenState(Elevator elevator){
        this.elevator=elevator;
    }
    @Override
    public void openDoor() {
        System.out.println("電梯門已經(jīng)打開");
    }
    @Override
    public void closeDoor() {
        System.out.println("電梯門關了");
        elevator.setCurrentState(elevator.getCloseState());
    }
    @Override
    public void moveUp() {
        System.out.println("電梯門打開狀態(tài),不能上升");
    }
    @Override
    public void moveDown() {
        System.out.println("電梯門打開狀態(tài),不能下降");
    }
    @Override
    public void stop() {
        System.out.println("電梯門打開狀態(tài),不能變換為停止狀態(tài)");
    }
}

/**
 * @Description: 停止狀態(tài)
 * @Date: 2025-02-08 9:59
 * @Author: gaoyufei
 **/
public class StopState implements ElevatorState{
    private Elevator elevator;
    public StopState(Elevator elevator){
        this.elevator=elevator;
    }
    @Override
    public void openDoor() {
        System.out.println("電梯門開了");
        elevator.setCurrentState(elevator.getOpenState());
    }
    @Override
    public void closeDoor() {
        System.out.println("電梯門關了");
        elevator.setCurrentState(elevator.getCloseState());
    }
    @Override
    public void moveUp() {
        System.out.println("電梯上升");
        elevator.setCurrentState(elevator.getMovingUpState());
    }
    @Override
    public void moveDown() {
        System.out.println("電梯下降");
        elevator.setCurrentState(elevator.getMovingDownState());
    }
    @Override
    public void stop() {
        System.out.println("電梯停止");
    }
}
/**
 * @Description: 上升狀態(tài)
 * @Date: 2025-02-08 9:07
 * @Author: gaoyufei
 **/
public class MovingUpState implements ElevatorState{
    private Elevator elevator;
    public MovingUpState(Elevator elevator){
        this.elevator=elevator;
    }
    @Override
    public void openDoor() {
        System.out.println("電梯正在上升，不能開門");
    }
    @Override
    public void closeDoor() {
        System.out.println("電梯已經(jīng)關門");
    }
    @Override
    public void moveUp() {
        System.out.println("電梯正在上升");
    }
    @Override
    public void moveDown() {
        System.out.println("電梯下降");
        elevator.setCurrentState(elevator.getMovingDownState());
    }
    @Override
    public void stop() {
        System.out.println("電梯停止");
        elevator.setCurrentState(elevator.getStopState());
    }
}

/**
 * @Description: 下降狀態(tài)
 * @Date: 2025-02-08 9:08
 * @Author: gaoyufei
 **/
public class MovingDownState implements ElevatorState{
    private Elevator elevator;
    public MovingDownState(Elevator elevator){
        this.elevator=elevator;
    }
    @Override
    public void openDoor() {
        System.out.println("電梯正在下降,不能開門");
    }
    @Override
    public void closeDoor() {
        System.out.println("電梯正在下降,已經(jīng)關門了");
    }
    @Override
    public void moveUp() {
        System.out.println("電梯上升");
        elevator.setCurrentState(elevator.getMovingUpState());
    }
    @Override
    public void moveDown() {
        System.out.println("電梯正在下降");
    }
    @Override
    public void stop() {
        System.out.println("電梯停止");
        elevator.setCurrentState(elevator.getStopState());
    }
}

/**
 * @Description: 電梯
 * @Date: 2025-02-08 9:04
 * @Author: gaoyufei
 **/
public class Elevator {
    private ElevatorState closeState;
    private ElevatorState openState;
    private ElevatorState movingDownState;
    private ElevatorState movingUpState;
    private ElevatorState stopState;

    private ElevatorState currentState;

    public Elevator(){
        closeState=new CloseState(this);
        openState=new OpenState(this);
        movingDownState=new MovingDownState(this);
        movingUpState=new MovingUpState(this);
        stopState=new StopState(this);
        currentState=closeState;// 默認初始狀態(tài)為關閉狀態(tài)

    }
    public void setCurrentState(ElevatorState currentState) {
        this.currentState = currentState;
    }
    public ElevatorState getCloseState() {
        return closeState;
    }
    public ElevatorState getOpenState() {
        return openState;
    }
    public ElevatorState getMovingDownState() {
        return movingDownState;
    }
    public ElevatorState getMovingUpState() {
        return movingUpState;
    }
    public ElevatorState getStopState() {
        return stopState;
    }
    public void openDoor(){
        currentState.openDoor();
    }
    public void closeDoor(){
        currentState.closeDoor();
    }
    public void moveUp(){
        currentState.moveUp();
    }
    public void moveDown(){
        currentState.moveDown();
    }
    public void stop(){
        currentState.stop();
    }
}

/**
 * @Description: 客戶端
 * @Date: 2025-02-08 9:29
 * @Author: gaoyufei
 **/
public class Client {
    public static void main(String[] args) {
        //初始關閉狀態(tài)
        Elevator elevator=new Elevator();
        //關門
        elevator.closeDoor();//輸出 電梯門已經(jīng)關了
        //開門
        elevator.openDoor();//輸出 電梯門開了
        //上升
        elevator.moveUp();//輸出 電梯門打開狀態(tài)不能上升
        //關門
        elevator.closeDoor();//輸出 電梯門關了
        //上升
        elevator.moveUp();//輸出 電梯上升
        //關門
        elevator.closeDoor();//輸出 電梯已經(jīng)關門
        //下降
        elevator.moveDown();//輸出 電梯下降
        //停止
        elevator.stop();//輸出 電梯停止
        //開門
        elevator.openDoor();//輸出 電梯門開了
        //停止
        elevator.stop();//輸出 電梯門打開狀態(tài),不能變換為停止狀態(tài)
    }
}

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