Spring MVC:如何返回自定义 404 错误页面?

问题描述

当找不到请求的资源时，我正在寻找一种干净的方法来返回 Spring 4 中的自定义 404 错误页面.对不同域类型的查询应该会导致不同的错误页面.

I'm looking for a clean way to return customized 404 errorpages in Spring 4 when a requested resource was not found. Queries to different domain types should result in different error pages.

这里有一些代码来表明我的意图(Meter 是一个域类):

Here some code to show my intention (Meter is a domain class):

@RequestMapping(value = "/{number}", method = RequestMethod.GET)
public String getMeterDetails(@PathVariable("number") final Long number, final Model model) {
    final Meter result = meterService.findOne(number);
    if (result == null) {
        // here some code to return an errorpage
    }

    model.addAttribute("meter", result);
    return "meters/details";
}

我想了几种处理问题的方法.首先，有可能创建 RuntimeException 像

I imagine several ways for handling the problem. First there would be the possibility to create RuntimeExceptions like

@ResponseStatus(HttpStatus.NOT_FOUND)
public class MeterNotFoundExcption extends RuntimeException { }

然后使用异常处理程序呈现自定义错误页面(可能包含指向仪表列表的链接或任何合适的内容).

and then use an exception handler to render a custom errorpage (maybe containing a link to a list of meters or whatever is appropriate).

但我不喜欢用许多小的例外来污染我的应用程序.

But I don't like polluting my application with many small exceptions.

另一种可能性是使用 HttpServletResponse 并手动设置状态码:

Another possibility would be using HttpServletResponse and set the statuscode manually:

@RequestMapping(value = "/{number}", method = RequestMethod.GET)
public String getMeterDetails(@PathVariable("number") final Long number, final Model model,
final HttpServletResponse response) {
    final Meter meter = meterService.findOne(number);
    if (meter == null) {
        response.setStatus(HttpStatus.NOT_FOUND.value());
        return "meters/notfound";
    }

    model.addAttribute("meter", meter);
    return "meters/details";
}

但使用此解决方案，我必须为许多控制器方法(如编辑、删除)复制前 5 行.

But with this solution I have to duplicate the first 5 lines for many controller methods (like edit, delete).

有没有一种优雅的方法可以防止多次重复这些行?

Is there an elegant way to prevent duplicating these lines many times?

推荐答案

解决方案比想象的要简单得多.可以使用一个通用的 ResourceNotFoundException 定义如下:

The solution is much simpler than thought. One can use one generic ResourceNotFoundException defined as follows:

public class ResourceNotFoundException extends RuntimeException { }

然后可以使用 ExceptionHandler 注释处理每个控制器中的错误:

then one can handle errors within every controller with an ExceptionHandler annotation:

class MeterController {
    // ...
    @ExceptionHandler(ResourceNotFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public String handleResourceNotFoundException() {
        return "meters/notfound";
    }

    // ...

    @RequestMapping(value = "/{number}/edit", method = RequestMethod.GET)
    public String viewEdit(@PathVariable("number") final Meter meter,
                           final Model model) {
        if (meter == null) throw new ResourceNotFoundException();

        model.addAttribute("meter", meter);
        return "meters/edit";
    }
}

每个控制器都可以为ResourceNotFoundException定义自己的ExceptionHandler.

Every controller can define its own ExceptionHandler for the ResourceNotFoundException.

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