java160109SingleDemo单例模式在线程中的运用

/**

* 单例设计模式在线程中的运用

*/

package java160109;

/**

* @author LiZheng

*

*/

public class SingleDemo {

/**

* @param args

*/

public static void main(String[] args) {

}

}

/**

*

*

*

* class Single { private static final Single single = new Single();

*

* private Single() { } public static Single getInstance() { return single;

*

* }

*

* }

*

*/

class Single {

private static Single single = null;

private Single() {

}

// public synchronized static Single getInstance 效率较低

public static Single getInstance() {

//双重判断减少锁的次数

if (single==null) {

synchronized (Single.class) {

if (single == null) {

single = new Single();

}

}

}

return single;

}

}