JAVA单例设计模式代码教程

JAVA单例设计模式代码教程

package com.company;
class Singleton{
    private static final Singleton SINGLETON = new Singleton();
    private Singleton(){}
    public void print(){
        System.out.println("HelloWord");
    }
    public static Singleton getSingleton(){
        return SINGLETON;
    }
}
public class Main {
    public static void main(String[] args) {
        Singleton singleton = Singleton.getSingleton();
        singleton.print();
    }
}

package com.company;
class Singleton{
    private static Singleton singleton;
    private Singleton(){}
    public void print(){
        System.out.println("HelloWord");
    }
    public static Singleton getSingleton(){
        if(singleton == null){
            singleton = new Singleton();
        }
        return singleton;
    }
}
public class Main {
    public static void main(String[] args) {
        Singleton singleton = Singleton.getSingleton();
        singleton.print();
    }
}