Java 디자인 패턴 이해: 일반적으로 사용되는 7가지 디자인 패턴 소개, 구체적인 코드 예제가 필요합니다.
Java 디자인 패턴은 소프트웨어 디자인 문제에 대한 보편적인 솔루션으로 널리 받아들여지는 디자인 아이디어와 행동 강령을 제공합니다. 디자인 패턴은 코드 구조를 더 잘 구성하고 계획하는 데 도움이 되므로 코드의 유지 관리, 읽기 및 확장성이 향상됩니다. 이 글에서는 Java에서 일반적으로 사용되는 7가지 디자인 패턴을 소개하고 해당 코드 예제를 제공합니다.
public class Singleton { private static Singleton instance; private Singleton() { // 私有构造函数,防止外部实例化 } public static Singleton getInstance() { if (instance == null) { synchronized (Singleton.class) { if (instance == null) { instance = new Singleton(); } } } return instance; } }
public interface Shape { void draw(); } public class Circle implements Shape { @Override public void draw() { System.out.println("Circle::draw()"); } } public class Rectangle implements Shape { @Override public void draw() { System.out.println("Rectangle::draw()"); } } public class ShapeFactory { public Shape getShape(String shapeType) { if (shapeType == null) { return null; } if (shapeType.equalsIgnoreCase("CIRCLE")) { return new Circle(); } else if (shapeType.equalsIgnoreCase("RECTANGLE")) { return new Rectangle(); } return null; } }
import java.util.ArrayList; import java.util.List; public class Subject { private List<Observer> observers = new ArrayList<>(); private int state; public int getState() { return state; } public void setState(int state) { this.state = state; notifyAllObservers(); } public void attach(Observer observer) { observers.add(observer); } public void notifyAllObservers() { for (Observer observer : observers) { observer.update(); } } } public abstract class Observer { protected Subject subject; public abstract void update(); } public class BinaryObserver extends Observer { public BinaryObserver(Subject subject) { this.subject = subject; this.subject.attach(this); } public void update() { System.out.println("Binary String: " + Integer.toBinaryString(subject.getState())); } } public class OctalObserver extends Observer { public OctalObserver(Subject subject) { this.subject = subject; this.subject.attach(this); } public void update() { System.out.println("Octal String: " + Integer.toOctalString(subject.getState())); } } public class HexObserver extends Observer { public HexObserver(Subject subject) { this.subject = subject; this.subject.attach(this); } public void update() { System.out.println("Hex String: " + Integer.toHexString(subject.getState())); } } public class ObserverPatternDemo { public static void main(String[] args) { Subject subject = new Subject(); new BinaryObserver(subject); new OctalObserver(subject); new HexObserver(subject); System.out.println("First state change: 15"); subject.setState(15); System.out.println("Second state change: 10"); subject.setState(10); } }
public class Computer { private String cpu; private String memory; private String disk; // 省略其他属性和方法 } public interface ComputerBuilder { ComputerBuilder setCpu(String cpu); ComputerBuilder setMemory(String memory); ComputerBuilder setDisk(String disk); Computer build(); } public class BasicComputerBuilder implements ComputerBuilder { private Computer computer; public BasicComputerBuilder() { computer = new Computer(); } public ComputerBuilder setCpu(String cpu) { computer.setCpu(cpu); return this; } public ComputerBuilder setMemory(String memory) { computer.setMemory(memory); return this; } public ComputerBuilder setDisk(String disk) { computer.setDisk(disk); return this; } public Computer build() { return computer; } } public class Director { private ComputerBuilder computerBuilder; public Director(ComputerBuilder computerBuilder) { this.computerBuilder = computerBuilder; } public Computer construct() { return computerBuilder .setCpu("i5") .setMemory("8GB") .setDisk("1TB") .build(); } } public class BuilderPatternDemo { public static void main(String[] args) { ComputerBuilder computerBuilder = new BasicComputerBuilder(); Director director = new Director(computerBuilder); Computer computer = director.construct(); System.out.println(computer.toString()); } }
public abstract class Shape implements Cloneable { private String id; protected String type; abstract void draw(); public String getId() { return id; } public void setId(String id) { this.id = id; } public Object clone() { Object clone = null; try { clone = super.clone(); } catch (CloneNotSupportedException e) { e.printStackTrace(); } return clone; } } public class Circle extends Shape { public Circle() { type = "Circle"; } public void draw() { System.out.println("Inside Circle::draw() method."); } } public class Rectangle extends Shape { public Rectangle() { type = "Rectangle"; } public void draw() { System.out.println("Inside Rectangle::draw() method."); } } public class ShapeCache { private static Map<String, Shape> shapeMap = new HashMap<>(); public static Shape getShape(String shapeId) { Shape cachedShape = shapeMap.get(shapeId); return (Shape) cachedShape.clone(); } public static void loadCache() { Circle circle = new Circle(); circle.setId("1"); shapeMap.put(circle.getId(), circle); Rectangle rectangle = new Rectangle(); rectangle.setId("2"); shapeMap.put(rectangle.getId(), rectangle); } } public class PrototypePatternDemo { public static void main(String[] args) { ShapeCache.loadCache(); Shape clonedShape1 = ShapeCache.getShape("1"); System.out.println("Shape: " + clonedShape1.getType()); Shape clonedShape2 = ShapeCache.getShape("2"); System.out.println("Shape: " + clonedShape2.getType()); } }
public interface MediaPlayer { void play(String audioType, String fileName); } public interface AdvancedMediaPlayer { void playVlc(String fileName); void playMp4(String fileName); } public class VlcPlayer implements AdvancedMediaPlayer { public void playVlc(String fileName) { System.out.println("Playing vlc file. Name: " + fileName); } public void playMp4(String fileName) { // 空实现 } } public class Mp4Player implements AdvancedMediaPlayer { public void playVlc(String fileName) { // 空实现 } public void playMp4(String fileName) { System.out.println("Playing mp4 file. Name: " + fileName); } } public class MediaAdapter implements MediaPlayer { AdvancedMediaPlayer advancedMediaPlayer; public MediaAdapter(String audioType) { if (audioType.equalsIgnoreCase("vlc")) { advancedMediaPlayer = new VlcPlayer(); } else if (audioType.equalsIgnoreCase("mp4")) { advancedMediaPlayer = new Mp4Player(); } } public void play(String audioType, String fileName) { if (audioType.equalsIgnoreCase("vlc")) { advancedMediaPlayer.playVlc(fileName); } else if (audioType.equalsIgnoreCase("mp4")) { advancedMediaPlayer.playMp4(fileName); } } } public class AudioPlayer implements MediaPlayer { MediaAdapter mediaAdapter; public void play(String audioType, String fileName) { if (audioType.equalsIgnoreCase("mp3")) { System.out.println("Playing mp3 file. Name: " + fileName); } else if (audioType.equalsIgnoreCase("vlc") || audioType.equalsIgnoreCase("mp4")) { mediaAdapter = new MediaAdapter(audioType); mediaAdapter.play(audioType, fileName); } else { System.out.println("Invalid media. " + audioType + " format not supported"); } } } public class AdapterPatternDemo { public static void main(String[] args) { AudioPlayer audioPlayer = new AudioPlayer(); audioPlayer.play("mp3", "beyond_the_horizon.mp3"); audioPlayer.play("mp4", "alone.mp4"); audioPlayer.play("vlc", "far_far_away.vlc"); audioPlayer.play("avi", "mind_me.avi"); } }
public interface Strategy { int doOperation(int num1, int num2); } public class OperationAdd implements Strategy { public int doOperation(int num1, int num2) { return num1 + num2; } } public class OperationSubtract implements Strategy { public int doOperation(int num1, int num2) { return num1 - num2; } } public class OperationMultiply implements Strategy { public int doOperation(int num1, int num2) { return num1 * num2; } } public class Context { private Strategy strategy; public Context(Strategy strategy) { this.strategy = strategy; } public int executeStrategy(int num1, int num2) { return strategy.doOperation(num1, num2); } } public class StrategyPatternDemo { public static void main(String[] args) { Context context = new Context(new OperationAdd()); System.out.println("10 + 5 = " + context.executeStrategy(10, 5)); context = new Context(new OperationSubtract()); System.out.println("10 - 5 = " + context.executeStrategy(10, 5)); context = new Context(new OperationMultiply()); System.out.println("10 * 5 = " + context.executeStrategy(10, 5)); } }
위의 예시 코드를 통해 자바에서 흔히 사용되는 7가지 디자인 패턴에 대해 간략하게 소개합니다. 각 디자인 패턴에는 서로 다른 시나리오와 애플리케이션이 있으며 서로 다른 프로젝트에서 작동할 수 있습니다. 이 글이 디자인 패턴을 이해하고 적용하며, 코드 품질과 개발 효율성을 높이는 데 도움이 되기를 바랍니다.
위 내용은 일반적으로 사용되는 7가지 Java 디자인 패턴에 대해 심층적으로 이해하세요.의 상세 내용입니다. 자세한 내용은 PHP 중국어 웹사이트의 기타 관련 기사를 참조하세요!