Java單例模式的三種執行緒安全版本
阿新 • • 發佈：2018-12-04
Double check
public class Singleton{
private static class SingletonHolder{
private static Singleton instance = new Singleton();
}
private Singleton(){}
public static Singleton newInstance(){
return SingletonHolder.instance;
}
}
靜態內部類保證執行緒安全
public class Singleton {
private static volatile Singleton instance = null;
private Singleton() {
} public static Singleton getInstance() {
if (instance == null) {
synchronized (Singleton.class) {
if (instance == null) {
instance = new Singleton();
}
} } return instance;
}
}
列舉保證執行緒安全，也可防反射
public enum Singleton{
instance;
public void whateverMethod(){}
}