1.双重校验
public class Singleton{
private volatile static Singleton instance;
private Singleton(){};
public static Singleton getInstance(){
if(null == instance){
synchronized(Singleton.class){
if(null == instance){
instance = new Singleton();
}
}
}
return instance;
}
}
2.懒汉式
- 线程不安全
public class Singleton{
private static Singleton instance;
private Singleton(){};
public static synchronized Singleton getInstance(){
if(null == instance){
instance = new Singleton();
}
return instance;
}
}
- 饿汉式
public class Singleton{
private static Singleton instance = new Singleton();
private Singleton(){};
public static Singleton getInstance(){
return instance;
}
}
