Spring @MVC 和 @RequestParam 验证
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Spring @MVC and @RequestParam validation
提问by Brandon Yarbrough
I would like to use the @RequestParam annotation like so:
我想像这样使用@RequestParam 注释：
@RequestMapping
public void handleRequest( @RequestParam("page") int page ) {
...
}
However, I want to show page 1 if the user fiddles with the URL parameters and tries to go to page "abz" or something non-numerical. Right now, the best I can get Spring to do is return a 500. Is there a way to override this behavior cleanly without having to take in the parameter as a String?
但是，如果用户摆弄 URL 参数并尝试转到页面“abz”或非数字页面，我想显示第 1 页。现在，我可以让 Spring 做的最好的事情是返回 500。有没有办法干净地覆盖这种行为而不必将参数作为字符串接受？
I looked at the @ExceptionHandler annotation, but it doesn't seem to do anything when I set I use @ExceptionHandler(TypeMismatchException.class). Not sure why not.
我查看了 @ExceptionHandler 注释，但是当我设置 I use 时它似乎没有做任何事情@ExceptionHandler(TypeMismatchException.class)。不知道为什么不。
Suggestions?
建议？
P.S. Bonus question: Spring MVC is called Spring MVC. Is Spring MVC with annotations just called Spring @MVC? Google treats them as the same name, which is annoying.
PS Bonus 问题：Spring MVC 被称为 Spring MVC。带有注释的 Spring MVC 只是称为 Spring @MVC 吗？谷歌将它们视为同名，这很烦人。
回答by Janning
The ConversionServiceis a nice solution, but it lacks a value if you give an empty string to your request like ?page=The ConversionService is simply not called at all, but pageis set to null(in case of Integer) or an Exception is thrown (in case of an int)
这ConversionService是一个不错的解决方案，但如果您为请求提供空字符串，则它缺少值，例如?page=根本没有调用 ConversionService，而是page设置为null（在 的情况下Integer）或抛出异常（在 的情况下int）
This is my preferred solution:
这是我的首选解决方案：
@RequestMapping
public void handleRequest( HttpServletRequest request ) {
int page = ServletRequestUtils.getIntParameter(request, "page", 1);
}
This way you always have a valid int parameter.
这样你总是有一个有效的 int 参数。
回答by axtavt
Since Spring 3.0, you can set a ConversionService. @InitBinder's valuespecifies a particular parameter to apply that service to:
从 Spring 3.0 开始，您可以设置一个ConversionService. @InitBinder'svalue指定一个特定参数以将该服务应用于：
@InitBinder("page")
public void initBinder(WebDataBinder binder) {
FormattingConversionService s = new FormattingConversionService();
s.addFormatterForFieldType(Integer.class, new Formatter<Integer>() {
public String print(Integer value, Locale locale) {
return value.toString();
}
public Integer parse(String value, Locale locale)
throws ParseException {
try {
return Integer.valueOf(value);
} catch (NumberFormatException ex) {
return 1;
}
}
});
binder.setConversionService(s);
}
