手写三种单例模式

话不多说直接上代码

package tesetSingle;

public class Test {
    public static void main(String[] args) {
        for (int i = 0; i < 3; i++) {
                    new Thread(()->{
                        //Hungry.getInstance();
                        LazyMan instanceL1 = LazyMan.getInstance();
                        LazyMan instanceL2 = LazyMan.getInstance();
                        System.out.println(instanceL1 == instanceL2);
                        System.out.println(instanceL1.equals(instanceL2));
                        EnumSingle instance = EnumSingle.INSTANCE.getInstance();
                        EnumSingle instance2 = EnumSingle.INSTANCE.getInstance();
                        System.out.println(instance == instance2);
                        System.out.println(instance.equals(instance2));
                    },String.valueOf(i)).start();
                }
    }
}
//饿汉式单例模式
class Hungry{
    private Hungry(){
        System.out.println(Thread.currentThread().getName()+"\tok");
    }
    private static Hungry hungry = new Hungry();
    public static Hungry getInstance(){
        return hungry;
    }
}

//懒汉式
class LazyMan{
    private LazyMan(){
        System.out.println(Thread.currentThread().getName()+"\tok");
    }
    private volatile static LazyMan lazyMan;
    public static LazyMan getInstance(){
        if (lazyMan == null){
            synchronized (LazyMan.class){
                if (lazyMan == null){
                    lazyMan = new LazyMan();
                }
            }
        }
        return lazyMan;
    }
}
//枚举 单例模式
enum EnumSingle{
    INSTANCE;
    public EnumSingle getInstance(){
        return INSTANCE;
    }
}