方法“def”可以用作“开始”语句：

def foo
  ...
rescue
  ...
end

您也可以在线救援：
将打印出“例外！“since 'String can't be coerced into Fixnum'

我在ActiveRecord验证中经常使用def / rescue组合：

def create
   @person = Person.new(params[:person])
   @person.save!
   redirect_to @person
rescue ActiveRecord::RecordInvalid
   render :action => :new
end

我认为这是非常精简的代码！

示例：

begin
  # something which might raise an exception
rescue SomeExceptionClass => some_variable
  # code that deals with some exception
ensure
  # ensure that this code always runs
end

这里，def作为begin语句：

def
  # something which might raise an exception
rescue SomeExceptionClass => some_variable
  # code that deals with some exception
ensure
  # ensure that this code always runs
end

奖励！你也可以用其他类型的块来做这个。例如：

[1, 2, 3].each do |i|
  if i == 2
    raise
  else
    puts i
  end
rescue
  puts 'got an exception'
end

在irb中输出：

1
got an exception
3
 => [1, 2, 3]