Question

 public static int take1()
  {
      Scanner in = new Scanner(System.in);
      while(true)
      {
          try
          {
              System.out.print("\nHow many coloms you want = ");
              return in.nextInt();
          }
          catch(Exception e )
          {
              System.out.println("Sorry,Please enter only no.");
              in.next();
          }

      }

  }

如何关闭扫描程序对象，如果我使用finally关闭此对象或尝试使用资源，它也会关闭System.in，并且我不能多次从流中读取。这样做的最佳方法是什么？

Answer 1

将finally阻止并关闭开放资源。

Java finally块是一个用于执行 重要代码的块，例如关闭连接，流等。

始终执行Java finally块。

 try
  {
      System.out.print("\nHow many coloms you want = ");
      return in.nextInt();
  } catch(Exception e ){
            System.out.println("Sorry,Please enter only no.");
            in.next();
   }finally{
            in.close();
   }

编辑AS Na Na Gala

检查是否发生异常然后关闭它让它进入下一个循环util no。进入，否则关闭它。

public static int take1()
    {
        boolean isExceptionOccured=false;
        Scanner in = new Scanner(System.in);
        while(true)
        {
            try
            {
                System.out.print("\nHow many coloms you want = ");
                isExceptionOccured=false;
                return in.nextInt();
            }
            catch(Exception e )
            {
                isExceptionOccured=true;
                System.out.println("Sorry,Please enter only no.");
                in.next();
            }finally{
                if(!isExceptionOccured){
                in.close();
                System.out.println("resource closed");
                }
            }

        }

    }

Answer 2

你应该用这个：

func signUp(_ email: String, username: String, password: String, data: Data!) {

    Auth.auth().createUser(withEmail: email, password: password, completion: { (user, error) in

        if error == nil {

            // error here
            self.setUserInfo(user, username: username, password: password, data: data)
        }else {
            print(error!.localizedDescription)
        }
    })
}

而不是finally { sc.reset(); }

Answer 3

在try中使用变量然后关闭。例如，

 public static int take1()
  {
      Scanner in = new Scanner(System.in);
      while(true)
      {
          try
          {
              System.out.print("\nHow many coloms you want = ");
              int i =  in.nextInt();
              in.close();
              return i;
          }
          catch(Exception e )
          {
              System.out.println("Sorry,Please enter only no.");
              in.next();
          }

      }

  }

此方法可帮助您关闭对象，避免最终阻止。

如何在try循环中关闭Scanner对象？

3 个答案: