单例-java-代码

public class Singleton { private static Singleton instance;

private Singleton() {
    // private constructor
}

public static Singleton getInstance() {
    if (instance == null) {
        synchronized (Singleton.class) {
            if (instance == null) {
                instance = new Singleton();
            }
        }
    }
    return instance;
}

}

//使用方法 Singleton singleton = Singleton.getInstance();