对单例模式使用双重检查锁定习惯用法是否更好?还是同步方法?
即:
private static volatile ProcessManager singleton = null;
public static ProcessManager getInstance() throws Exception {
if (singleton == null) {
synchronized (MyClass.class) {
if (singleton == null) {
singleton = new ProcessManager();
}
}
}
return singleton;
或
private static processManager singleton = null;
public synchronized static processManager getInsatnce() throws Exception {
if(singleton == null) {
singleton = new processManager();
}
return singleton
}
最佳答案
让 ClassLoader 为您完成工作:
/*
* This solution takes advantage of the Java memory model's guarantees about class initialization
* to ensure thread safety. Each class can only be loaded once, and it will only be loaded when it
* is needed. That means that the first time getInstance is called, mySingletonServiceLoader
* will be loaded and instance will be created, and since this is controlled by ClassLoaders,
* no additional synchronization is necessary.
*/
public static DocumentService getInstance() {
return mySingletonServiceLoader.INSTANCE;
}
private static class mySingletonServiceLoader {
static DocumentService INSTANCE = new DocumentService();
}
}
关于java - 对单例模式使用双重检查锁定习惯用法是否最佳?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15526915/