Question

我知道有一个开始救援结束的标准技术

如何单独使用救援区。

它是如何工作的以及它如何知道正在监视哪些代码？

Answer 1

方法“def”可以作为“开始”语句：

def foo
  ...
rescue
  ...
end

Answer 2

你也可以内联救援：

1 + "str" rescue "EXCEPTION!"

将打印出“EXCEPTION！”因为'String不能强制进入Fixnum'

Answer 3

我正在使用def / rescue组合与ActiveRecord验证：

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

我认为这是非常精益的代码！

Answer 4

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

此处，def为begin声明：

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

Answer 5

奖金！您也可以使用其他种类的块来执行此操作。例如：

#rightModal .modal-dialog-slideout {
  min-height: 100%;
  margin: 0 0 0 auto;
  background: #fff;
}

.modal.fade .modal-dialog.modal-dialog-slideout {
  -webkit-transform: translate(100%, 0)scale(1);
  transform: translate(100%, 0)scale(1);
}

.modal.fade.show .modal-dialog.modal-dialog-slideout {
  -webkit-transform: translate(0, 0);
  transform: translate(0, 0);
  display: flex;
  align-items: stretch;
  height: 100%;
}

.modal.fade.show .modal-dialog.modal-dialog-slideout .modal-body {
  overflow-y: auto;
  overflow-x: hidden;
}

.modal-dialog-slideout .modal-content {
  border: 0;
}

.modal-dialog-slideout .modal-header,
.modal-dialog-slideout .modal-footer {
  height: 69px;
  display: block;
}

#rightModal .modal-dialog-slideout .modal-header h5 {
  float: left;
  color: blue;
}

#leftModal .modal-dialog-slideout {
  min-height: 100%;
  margin: 0 auto 0 0;
  background: #fff;
}

#leftModal .modal-dialog-slideout .modal-header h5 {
  float: left;
  color: red;
}

#leftModal.modal.fade:not(.show) .modal-dialog.modal-dialog-slideout {
  -webkit-transform: translate(100%, 0)scale(1);
  transform: translate(-100%, 0)scale(1);
}

在 <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script> <div class="container"> <div class="row"> <div class="col"> <h1>Some heading</h1> <p>This is not a love song</p> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#leftModal">Left</button> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#rightModal">Right</button> <button type="button" class="btn btn-primary" data-toggle="modal" data-target="#middleModal">Middle</button> </div> </div> </div>  <div class="modal fade" id="rightModal" tabindex="-1" role="dialog" aria-labelledby="rightModalLabel" aria-hidden="true"> <div class="modal-dialog modal-dialog-slideout" role="document"> <div class="modal-content"> <div class="modal-header"> <h5 class="modal-title" id="rightModalLabel">Right On</h5> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> Right Modal </div> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button> <button type="button" class="btn btn-primary">Save changes</button> </div> </div> </div> </div>  <div class="modal fade" id="leftModal" tabindex="-1" role="dialog" aria-labelledby="leftModalLabel" aria-hidden="true"> <div class="modal-dialog modal-dialog-slideout" role="document"> <div class="modal-content"> <div class="modal-header"> <h5 class="modal-title" id="leftModalLabel">Left On</h5> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> Left Modal </div> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button> <button type="button" class="btn btn-primary">Save changes</button> </div> </div> </div> </div>   <div class="modal fade" id="middleModal" tabindex="-1" role="dialog" aria-labelledby="middleModalLabel" aria-hidden="true"> <div class="modal-dialog" role="document"> <div class="modal-content"> <div class="modal-header"> <h5 class="modal-title" id="middleModalLabel">Middle Modal</h5> <button type="button" class="close" data-dismiss="modal" aria-label="Close"> <span aria-hidden="true">×</span> </button> </div> <div class="modal-body"> ... </div> <div class="modal-footer"> <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button> </div> </div> </div> </div>中输出：

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

如何在没有开始和结束块的情况下在Ruby中使用rescue

5 个答案: