Open addcn opened 8 years ago
实际上，早在JDK1.5就引入volatile关键字，所以又有了一种更好的双重校验锁写法：
'''
public class Singleton{
private volatile static Singleton singleton; private Singleton (){} public static Singleton getSingleton(){ if(singleton == null){ synchronized (Singleton.calss){ if(singleton ==null){singleton = new Singleton();} } } }
} '''
http://mp.weixin.qq.com/s?__biz=MzA4MjU5NTY0NA==&mid=404388098&idx=1&sn=8bbbba7692dca68cdda2212dec4d86c0&scene=1&srcid=0320gXPloap70ixGeYnNUaAW#wechat_redirect
Java 单例真的写对了么?
‘’‘ private static volatile SettingsDbHelper sInst = null; // <<< 这里添加了 volatile public static SettingsDbHelper getInstance(Context context) { SettingsDbHelper inst = sInst; // <<< 在这里创建临时变量 if (inst == null) { synchronized (SettingsDbHelper.class) { inst = sInst; if (inst == null) { inst = new SettingsDbHelper(context); sInst = inst; } } } return inst; // <<< 注意这里返回的是临时变量 } ’‘’ http://www.race604.com/java-double-checked-singleton/
实际上，早在JDK1.5就引入volatile关键字，所以又有了一种更好的双重校验锁写法：
'''
public class Singleton{
} '''
http://mp.weixin.qq.com/s?__biz=MzA4MjU5NTY0NA==&mid=404388098&idx=1&sn=8bbbba7692dca68cdda2212dec4d86c0&scene=1&srcid=0320gXPloap70ixGeYnNUaAW#wechat_redirect
Java 单例真的写对了么?
‘’‘ private static volatile SettingsDbHelper sInst = null; // <<< 这里添加了 volatile
public static SettingsDbHelper getInstance(Context context) {
SettingsDbHelper inst = sInst; // <<< 在这里创建临时变量 if (inst == null) { synchronized (SettingsDbHelper.class) { inst = sInst; if (inst == null) { inst = new SettingsDbHelper(context); sInst = inst; } } } return inst; // <<< 注意这里返回的是临时变量 } ’‘’ http://www.race604.com/java-double-checked-singleton/