- 饿汉式
public class Singleton{
public static final Singleton instance = new Singleton();
private Singleton(){}
public static Singleton getInstance(){
return instance;
}
}
- 懒汉式之方法同步
public class Singleton{
public static final Singleton instance = null;
private Singleton(){}
public static synchronized Singleton getInstance(){
if(instance == null){
instance = new Singleton();
}
return instance;
}
}
- 懒汉式之双重检查
public class Singleton{
public static final Singleton instance = null;
private Singleton(){}
public static Singleton getInstance(){
if(instance==null){
synchronized（Singleton.class）{
if(instance==null){
instance = new Singleton();
}
}
}
return instance;
}
}
- 静态内部类
public class Singleton {
private static class SingletonHolder {
private static final Singleton INSTANCE = new Singleton();
}
private Singleton (){}
public static final Singleton getInstance() {
return SingletonHolder.INSTANCE;
}
}
