只有在行尾使用`rescue`才能捕獲異常，但在使用`begin rescue`塊時則不會

Question

我的聲明失敗了：

result = service.load_data()

現在以下抑制錯誤，然后我可以檢查nil

result = service.load_data() rescue nil

但是當我執行以下操作時，初始錯誤會被拋到UI，我不會得到異常的details 。

begin
   result = service.load_data()
rescue => details         
   logger.fatal "Failed to load the data: #{details}"
end

我確信我必須缺少一個愚蠢的細節，但我似乎無法在這里發現問題。 那么為什么不調用rescue區？

更新：我得到的錯誤是這樣的：

getaddrinfo: nodename nor servname provided, or not known

Answer 1

begin
   result = service.load_data()
rescue AnExceptionKlass => details    # here the name is SocketError    
   logger.fatal "Failed to load the data: #{details}"
end

使用上面的。

試圖在這里復制錯誤，如下所示：

require 'net/http'
Net::HTTP.start('http://www.google.com') do |http|
response = http.get('/')
puts response
end
#=> getaddrinfo: No such host is known.  (SocketError)

修正如下：

require 'net/http'

begin

  htt = Net::HTTP.start('http://www.google.com')
  response = htt.get('/')
  puts response

rescue SocketError => details    # or the Exception class name may be SocketError    
   p "Failed to load the data: #{details}"
end

#=> "Failed to load the data: getaddrinfo: No such host is known. "