1.简单解释:在创建对象时,无论创建多少次,在堆空间上只会申请一次内存空间。
2.例子(1):
public class Singleton{
private static Singleton _singleton = null;
//锁
private static Object singleton_lock = new Object();
//构造函数私有化
private Singleton(){
//初始化代码
}
public static Singleton CreateInstance(){
if(_singleton == null) //先看看是否初始化过,避免每次进入都要判断锁
{
lock(_singleton_lock){ //防止多个线程进入
if(_singleton == null){ //判断单例对象是否为null
_singleton = new Singleton();
}
}
}
return _singleton;
}
}
例子(2):
public class Singleton{
private static Singleton _singleton = null;
//构造函数私有化
private Singleton(){
//初始化代码
}
//静态构造函数
static Singleton(){
_singleton = new Singleton();
}
public static Singleton CreateInstance(){
return _singleton;
}
}
例子(3):
public class Singleton{
private static Singleton _singleton = new Singleton();
//构造函数私有化
private Singleton(){
//初始化代码
}
public static Singleton CreateInstance(){
return _singleton;
}
}