在类的内部讲构造器私有化,创建一个static的构造方法,就是静态工厂方法替代构造器。
最简单的一个静态工厂方法替代构造器示例:(好处就是创造时更清晰)
            
            
              csharp
              
              
            
          
          public class Book {
    private String title;
    private String author;  
    // 私有构造函数,防止直接实例化
    private Book(String title, String author) {
        this.title = title;
        this.author = author;
    }
    // 静态工厂方法
    public static Book createBookByTitleAndAuthor(String title, String author) {
        return new Book(title, author);
    }
}单例模式,多例模式,池化模式下,使用静态工厂方法,有一定优势:(静态工厂方法的最重要的优点)
            
            
              csharp
              
              
            
          
          public class Car{
	private static final Map<String,Car> carPool=new HashMap<>();
	private String model;
	private Car(model){
		this.model=model;
	}
	public static Car createCar(String model){
		Car car=carPool.get(model);
		if(car==null){
			car=new Car(model);
			carPool.put(model,car);
		}
		return car;
	}
}使用一个接口来实现静态工厂方法:
            
            
              csharp
              
              
            
          
          public interface Car {
    void drive();
    
    static Car createCar(String type) {
        if (type.equalsIgnoreCase("Sedan")) {
            return new Sedan();
        } else if (type.equalsIgnoreCase("SUV")) {
            return new SUV();
        }
        throw new IllegalArgumentException("Unknown car type");
    }
    class Sedan implements Car {
        @Override
        public void drive() {
            System.out.println("Driving a Sedan");
        }
    }
    class SUV implements Car {
        @Override
        public void drive() {
            System.out.println("Driving an SUV");
        }
    }
}
public class Main {
    public static void main(String[] args) {
        Car sedan = Car.createCar("Sedan");
        sedan.drive();  // 输出: Driving a Sedan
        Car suv = Car.createCar("SUV");
        suv.drive();  // 输出: Driving an SUV
    }
}