Hibernate，Spring，@Transactional - 用try / catch包围？ [英] Hibernate, Spring, @Transactional - surround with try/catch?

问题描述

我正在使用Spring 3和Hibernate 3.6开发Web应用程序。我对 @Transactional Annotation和代码结构提出了一些问题。

- >当我使用 @Transactional （使用Spring进行事务管理），是否必须使用try / catch来包围 @Transactional - 注解方法调用它们？

例如，当我得到一个加载，更改和返回的方法，然后我从另一个类调用它时：是否必须包围呼叫与try / catch？也许出了什么问题，没有对象返回，数据库连接失败..我不知道。

到现在为止，我认为 @Transactional 关心所有可能发生的异常，并在发生错误时回滚此事务中的每个操作。
，但如果发生，我必须以某种方式通知用户。当我调用try-block中的transactional-method并且它被回滚时，catch块被激活？
我可以告诉用户出错了。否则，用户可能不会被通知？

或者是否足以检查是否有返回的对象（if / else），那么我不需要try / catch？
Im新的，我想听听其他代码结构如何。谢谢： - ）

解决方案

非常简单。我倾向于使用@ExceptionHandler。

您可以使用 @ ExceptionHandler 来处理特定的异常，而不是在try-catch块中自己处理。

如果用户想要一个未找到的资源，并且您想发送一个404.

  @ResponseStatus（HttpStatus.NOT_FOUND）
 public void handleNotFoundException（NotFoundException exc）{
 //记录一些东西。 
} 
  

如果有服务器问题需要发送500

  @ExceptionHandler（SomeException.class）
 public void handleException（SomeException exc，WebRequest请求，HttpServletResponse响应）{
 response.sendError（HttpServletResponse.SC_INTERNAL_SERVER_ERROR，对不起，我的服务器坏了）; 
} 
  

您也应该狭义地处理异常。一般来说，你不应该做 @ExceptionHandler（Exception.class），我也相信它按顺序工作，所以如果你处理一般异常，它应该是最后一个方法。

Im working on developing a webapplication with Spring 3 and Hibernate 3.6. Ive got some questions to the @Transactional Annotation and the structure of the code.

-> When I use @Transactional (transaction management with Spring), do I have to surround the @Transactional-annotated methods with try/catch when calling them?

For example, when I got a method which loads, changes and returns then an object and I call it from another class: do I have to surround the call with try/catch? maybe something goes wrong, no object is returned, database connection fails.. I dont know.

until now, I thought @Transactional cares for all possible occurring exceptions and rolls back every operation in this transaction when an error occurs. but if it occurs, I must inform the user somehow. when I call the transactional-method in the try-block and it is rolled back, the catch block is activated? I can tell then the user "something did go wrong". Otherwise the user maybe would not be informed?

Or is it sufficient to check if there is an object returned (if/else), then I dont need try/catch? Im new and I would like to hear how other structure their code. Thank you :-)

解决方案

Handling exceptions in Spring is really easy with HandlerExceptionResolvers and @ExceptionHandlers. I tend to use @ExceptionHandler exclusively.

You can use an @ExceptionHandler to handle a specific exception instead of handling it yourself in a try-catch block.

If the user wanted a resource that wasn't found and you want to send a 404.

@ExceptionHandler(NotFoundException.class)
@ResponseStatus(HttpStatus.NOT_FOUND)
public void handleNotFoundException(NotFoundException exc) {
  // log something.
}

If there was a Server issue where you'd want to send a 500

@ExceptionHandler(SomeException.class)
public void handleException(SomeException exc, WebRequest request, HttpServletResponse response) {
    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Sorry dude, my server broke");
}

You also should narrowly handle the exceptions. In general you shouldn't do @ExceptionHandler(Exception.class) and I also believe that it works in order, so if you do handle the general Exception it should be the last method in the class.

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