Java Errors/BindingResult 参数应在模型属性、@RequestBody 或 @RequestPart 参数之后立即声明
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An Errors/BindingResult argument is expected to be declared immediately after the model attribute, the @RequestBody or the @RequestPart arguments
提问by CodeMed
I am teaching myself Spring by dissecting example applications and then adding code here and there to test theories that I develop during the dissection. I am getting the following error message when testing some code that I added to a Spring application:
我通过剖析示例应用程序来自学 Spring，然后在这里和那里添加代码来测试我在剖析过程中开发的理论。在测试我添加到 Spring 应用程序的一些代码时，我收到以下错误消息：
An Errors/BindingResult argument is expected to be declared immediately after the
model attribute, the @RequestBody or the @RequestPart arguments to which they apply
The method to which the error message refers is:
错误信息所指的方法是：
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(Integer typeID, BindingResult result, Map<String, Object> model) {
// find owners of a specific type of pet
typeID = 1;//this is just a placeholder
Collection<Owner> results = this.clinicService.findOwnerByPetType(typeID);
model.put("selections", results);
return "owners/catowners";
}
This error message was triggered when I tried to load the /catowners url pattern in the web browser. I have reviewed this pageand this posting, but the explanation does not seem clear.
当我尝试在 Web 浏览器中加载 /catowners url 模式时触发了此错误消息。我已经查看了这个页面和这个帖子，但解释似乎不清楚。
Can anyone show me how to fix this error, and also explain what it means?
谁能告诉我如何解决这个错误，并解释它的含义？
EDIT:
Based on Biju Kunjummen's response, I changed the syntax to the following:
编辑：
根据 Biju Kunjummen 的回应，我将语法更改为以下内容：
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(@Valid Integer typeID, BindingResult result, Map<String, Object> model)
I am still getting the same error message. Is ther something I am not understanding?
我仍然收到相同的错误消息。有什么我不明白的吗？
SECOND EDIT:
第二次编辑：
Based on Sotirios's comment, I changed the code to the following:
根据 Sotirios 的评论，我将代码更改为以下内容：
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(BindingResult result, Map<String, Object> model) {
// find owners of a specific type of pet
Integer typeID = 1;//this is just a placeholder
Collection<Owner> results = this.clinicService.findOwnerByPetType(typeID);
model.put("selections", results);
return "owners/catowners";
}
I am still getting the same error message after telling eclipse to run as...run on server again.
在告诉 eclipse 运行为...再次在服务器上运行后，我仍然收到相同的错误消息。
Is there something that I am not understanding?
有什么我不明白的吗？
采纳答案by Sotirios Delimanolis
Spring uses an interface called HandlerMethodArgumentResolverto resolve the parameter in your handler methods and construct an object to pass as an argument.
Spring 使用一个被调用的接口HandlerMethodArgumentResolver来解析处理程序方法中的参数并构造一个对象作为参数传递。
If it doesn't find one, it passes null(I have to verify this).
如果没有找到，则通过null（我必须验证这一点）。
The BindingResultis a result object that holds errors that may have come up validating a @ModelAttribute, @Valid, @RequestBodyor @RequestPart, so you can only use it with parameters that are annotated as such. There are HandlerMethodArgumentResolverfor each of those annotations.
该BindingResult是保存可能已经拿出了一个验证错误，结果对象@ModelAttribute，@Valid，@RequestBody或者@RequestPart，这样你就可以只与这样的注释参数使用它。HandlerMethodArgumentResolver这些注释中的每一个都有。
EDIT (response to comment)
编辑（对评论的回应）
Your example seems to show that the user should provide a pet type (as an integer). I would change the method to
您的示例似乎表明用户应该提供宠物类型（作为整数）。我会将方法更改为
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(@RequestParam("type") Integer typeID, Map<String, Object> model)
And you would make your request (depending on your config) as
你会提出你的请求（取决于你的配置）
localhost:8080/yourcontext/catowners?type=1
Here too there is nothing to validate so you don't want or need a BindingResult. It would fail if you tried to add it anyway.
这里也没有什么需要验证的，所以你不需要或不需要BindingResult. 如果您无论如何都尝试添加它，它将失败。
回答by Biju Kunjummen
If you have a parameter of type BindingResultit is essentially to hold any errors when binding http request parameters to a variable declared directly preceding the BindingResult method parameter.
如果您有一个类型的参数，BindingResult那么在将 http 请求参数绑定到直接在 BindingResult 方法参数之前声明的变量时，它本质上是保留任何错误。
So all of these is acceptable:
所以所有这些都是可以接受的：
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(@Valid MyType type, BindingResult result, ...)
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(@ModelAttribute MyType type, BindingResult result, ...)
@RequestMapping(value = "/catowners", method = RequestMethod.GET)
public String findOwnersOfPetType(@RequestBody @Valid MyType type, BindingResult result, ...)
