线程安全的单例模式

来源：互联网发布：网天概预算软件编辑：程序博客网时间：2024/06/10 11:36

public class SafeLazyInitialization {    private static Resource resource;    public synchronized static Resource getInstance() {       if (resource == null)          resource = new Resource();      return resource;    }}

public class EagerInitialization {   private static Resource resource = new Resource();  public static Resource getResource() { return resource; } }

//延迟初始化public class ResourceFactory {     private static class ResourceHolder {         public static Resource resource = new Resource();    }    public static Resource getResource() {         return ResourceHolder.resource ;     }}

public class SingletonDemo {     //注意需要volatile    private static volatile SingletonDemo instance = null;    private SingletonDemo() {  }    public static SingletonDemo getInstance() {        if (instance == null) { //二次检查，比直接用独占锁效率高               synchronized (SingletonDemo .class){                    if (instance == null) {                               instance = new SingletonDemo ();                     }             }        }        return instance;    }}

阅读全文

0 0