方式1(推荐)
package singleton;
public class Singletion {
private static class InnerSingletion {
private static Singletion single = new Singletion();
}
public static Singletion getInstance(){
return InnerSingletion.single;
}
}
方式2(double check)
package singleton;
public class DubbleSingleton {
private static DubbleSingleton ds;
public static DubbleSingleton getDs(){
if(ds == null){
try {
//模拟初始化对象的准备时间...
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (DubbleSingleton.class) {
if(ds == null){
ds = new DubbleSingleton();
}
}
}
return ds;
}
public static void main(String[] args) {
Thread t1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println(DubbleSingleton.getDs().hashCode());
}
},"t1");
Thread t2 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println(DubbleSingleton.getDs().hashCode());
}
},"t2");
Thread t3 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println(DubbleSingleton.getDs().hashCode());
}
},"t3");
t1.start();
t2.start();
t3.start();
}
}