第一种：同步
public class Singleton {
private static Singleton instance;
private Singleton() {
}
public synchronized static Singleton getInstance() {
if (instance == null) {
instance = new Singleton();
}
return instance;
}
}
第二种：静态初始化
public class Singleton {
private static Singleton instance = new Singleton();
private Singleton() {
}
public static Singleton getInstance() {
return instance;
}
}
第三种：静态holder类
public class Singleton {
private Singleton() {
}
private static class SingletonHolder {
public static Singleton instance = new Singleton();
}
public static Singleton getInstance() {
return SingletonHolder.instance;
}
}
编辑特别推荐: