1.public class Singleton {
private static class SingletonHolder {
public static Singleton resource = new Singleton();
public static Singleton getResource() {
return SingletonHolder.resource ;
private Singleton(){
2.public class Singleton {
public static final Singleton INSTANCE = new Singleton();
private Singleton(){}
public void method(){
public static void main(String[] a){
//调用方法。
Singleton.INSTANCE.method();
3.* 利用枚举巧妙创建单实例
public enum Singleton {
INSTANCE;http://www.huiyi8.com/jiaoben/
public void method(){ 网页特效代码
public static void main(String[] a){
//调用方法。
Singleton.INSTANCE.method();
public class Singleton {
4. private static volatile Singleton instance = null;
* 防止其他人new对象
private Singleton(){
System.out.println("init");
public static Singleton getInstance(){
if(instance == null){
synchronized(Singleton.class){
if(instance == null){
instance = new Singleton();
return instance;
