java编程技巧累积(持续更新）

@SuppressWarnings("unchecked")
public static <T> T deepCloneObject(T obj) {
	try {
		ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
		ObjectOutputStream out = new ObjectOutputStream(byteOut);
		out.writeObject(obj);
		
		ByteArrayInputStream byteIn = new ByteArrayInputStream(byteOut.toByteArray()); 
        ObjectInputStream in =new ObjectInputStream(byteIn);
		
        return (T)in.readObject();
	} catch (IOException e) {
		e.printStackTrace();
	} catch (ClassNotFoundException e) {
		e.printStackTrace();
	}
	return null;
}

Runtime.getRuntime().addShutdownHook(new Thread(){
          @Override
          public void run() {
              httpServer.destroy();
              producer.close();
          }
      });
     //lambda
     Runtime.getRuntime().addShutdownHook(new Thread(() ->{
          httpServer.destroy();
          producer.close();
      }));

public class Singleton {
    public static class SingletonHolder {
        private static final Singleton INSTANCE = new Singleton();
    }

    private Singleton() {}

    public static final Singleton getInstance() {
        return SingletonHolder.INSTANCE;
    }
}

public enum Singleton {
    INSTANCE;
    // 这里隐藏了一个空的私有构造方法
    //private Singleton () {
    //		System.out.println("Here");
    //}
}

//If you then added another class with a main() method like
public static void main(String[] args) {
    System.out.println(MySingleton.INSTANCE);
}
//You would see
Here
INSTANCE

// 定义单例模式中需要完成的代码逻辑
public interface MySingleton {
    void doSomething();
}

public enum Singleton implements MySingleton {
    INSTANCE {
        @Override
        public void doSomething() {
            System.out.println("complete singleton");
        }
    };

    public static MySingleton getInstance() {
        return Singleton.INSTANCE;
    }
}