java - Spring MVC 什么时候不需要 @RequestParam 注解？

Question

我正在查看一些 Spring 3 MVC Controller 代码，我看到 @RequestParam 用于某些参数而不用于其他参数。未使用的示例:

@RequestMapping(value = "/experiments", method = RequestMethod.GET)
public String getExperimentsPage(ExperimentSearchCriteria criteria, Map<String, Object> model) {
    // method body here
}

什么时候不需要@RequestParam(或类似的参数指定注解)？

Answer 1

好问题，我也一直想知道这个问题，直到我发现它在文档中被提及:

Note that use of @RequestParam is optional, e.g. to set its attributes. By default any argument that is a simple value type, as determined by BeanUtils#isSimpleProperty, and is not resolved by any other argument resolver, is treated as if it was annotated with @RequestParam.

https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-ann-requestparam

大多数时候，我不会指定它，除非我的方法参数名称与请求参数不同，或者，如果该值是可选的，我将需要使用 required=false .