@ModelAttribute vs @RequestBody，@ResponseBody

Question

@ModelAttribute

RequestMapping(value="/owners/{ownerId}/pets/{petId}/edit", method = 
RequestMethod.POST)
public String processSubmit(@ModelAttribute Pet pet) { }

http://.../?name=Something&age=100
public String doSomething(@ModelAttribute User user) { }

@RequestBody

@RequestMapping(value = "/user/savecontact", method = RequestMethod.POST
public String saveContact(@RequestBody Contact contact){ }

{ "name": "Something", "age": "100" } in request body
public String doSomething(@RequestBodyUser user) { }

@ModelAttribute将接受一个查询字符串。因此，所有数据都通过url传递给服务器。

@RequestBody，所有数据将通过完整的JSON体传递给服务器

1. 现在哪一个是最好的方法？
2. 如果两者都是为了相同的目的绑定到bean..which，那么一个是最佳实践还是被广泛用作标准实践？
3. 这两种方法都处理多部分文件，并且它们是否都具有相互等效的选项？https://javabeat.net/spring-multipart-file-upload/ How do i upload/stream large images using Spring 3.2 spring-mvc in a restful way
4. 他们中有谁的能力比另一个弱吗？就像长度限制，方法限制。弊端
5. 哪一个在安全性方面更安全？

Answer 1

正如javadoc所建议的那样，正是这种用法将它们区分开来，也就是说，如果要将对象绑定回web视图，则使用@ModelAttribute，如果不需要使用@RequestBody，则使用@RequestBody

• @RequestBody

- Usecases : Restful controllers (ex: produce and consume json/xml, processing direct document download requests, searching for stuff, ajax requests )
- As the name suggests the if a method argument is annotated with @RequestBody annotation Spring converts the HTTP request body to the Java type of the method argument.
- Is only allowed on method parameters (@Target(value={ PARAMETER}))
- The body of the request is passed through an HttpMessageConverter to resolve the method argument depending on the content type of the request.
- works for Post and not Get method.

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• @ModelAttribute

- Usecases : web app controllers (ex: binding request query parameters, populating web views with options and defaults)
- Uses data binders & ConversionService
- Is allowed on methods and method params(@Target(value={METHOD, PARAMETER}))
- Useful when dealing with model attributes for adding and retrieving model attributes to and from the Srping’s Model object
- When used on METHODS, those methods are invoked before the controller methods annotated with @RequestMapping are invoked 
- binds a method PARAMETER or method return value to a named model attribute & the bound named model attributes are exposed to a web view
- binds request query parameters to bean

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有关数据绑定和类型转换的详细信息，请参阅：https://docs.spring.io/spring/docs/5.1.x/spring-framework-reference/core.html#validation