Question

我有一个自定义异常，我想要提升并获救多次，因为执行该方法会导致错误。我知道它最终会导致无异常结果。

使用begin / rescue / end，似乎抛出异常并调用了rescue块，如果再次抛出异常，程序将离开begin / rescue / end块，错误将结束程序。如何在程序达到正确结果之前保持程序运行？另外，我对正在发生的事情的看法不正确吗？

这基本上就是我想要发生的事情（但显然是尽可能使用代码干......这段代码只是为了说明而不是我实现的内容。）

ships.each do |ship|
  begin
    orientation = rand(2) == 1 ? :vertical : :horizontal
    cell_coords = [rand(10), rand(10)] 
    place_ship(ship, orientation, cell_coords)
  rescue OverlapError  #if overlap error happens twice in a row, it leaves?
    orientation = rand(2) == 1 ? :vertical : :horizontal
    cell_coords = [rand(10), rand(10)] 
    place_ship(ship, orientation, cell_coords)
  rescue OverlapError
    orientation = rand(2) == 1 ? :vertical : :horizontal
    cell_coords = [rand(10), rand(10)] 
    place_ship(ship, orientation, cell_coords)
  rescue OverlapError
    orientation = rand(2) == 1 ? :vertical : :horizontal
    cell_coords = [rand(10), rand(10)] 
    place_ship(ship, orientation, cell_coords)
  #keep rescuing until the result is exception free
  end
end

Answer 1

您可以使用retry：

ships.each do |ship|
  begin
    orientation = rand(2) == 1 ? :vertical : :horizontal
    cell_coords = [rand(10), rand(10)] 
    place_ship(ship, orientation, cell_coords)
  rescue OverlapError  #if overlap error happens twice in a row, it leaves?
    retry
  end
end

无论如何，我不得不说你不应该使用异常作为控制流。我建议您，如果预计place_ship失败，则应返回true / false结果，并且您应该将代码包含在标准do while循环中。

如何重复处理异常直到正确结果？

1 个答案: