Java 如何在spring MVC中将@RequestParam绑定到对象？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/36003330/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to bind @RequestParam to object in spring MVC?
提问by user3029929
I want to make a POST request through AJAX, and I also want to bind the whole class object to the request, and I want to receive that request with @requestParamannotation. I know it can be done with @requestBodyannotation, but I am curious to know: can we do it with @requestParamannotation?
我想通过 AJAX 发出 POST 请求，并且我还想将整个类对象绑定到该请求，并且我想通过@requestParam注释接收该请求。我知道它可以通过@requestBody注释来完成，但我很想知道：我们可以用@requestParam注释来完成吗？
An Ajax code:
一个 Ajax 代码：
var restDTO{
id: 3,
name: "hello"
}
$.ajax({
url: url,
type: 'POST',
dataType: 'json',
contentType: 'application/json',
mimeType: 'application/json',
data: JSON.stringify({RestDTO : restDTO}),
success: function(data)
{
}
I do have RestDTO
我有 RestDTO
Class RestDTO
{
int id;
String name;
//getter and setter
}
In controller
在控制器中
public String content(@RequestParam RestDTO restDTO){...}
What should I do the make this code run?
我该怎么做才能运行此代码？
What should I change in sending data from ajax?
从ajax发送数据我应该改变什么？
Do I need to change on server to receive an RestDto object with @requestParamannotation?
我是否需要在服务器上进行更改以接收带有@requestParam注释的 RestDto 对象？
回答by Master Slave
If you're sending your data as classic request params, you can bind to object by simply omitting the @RequestParam, so
如果您将数据作为经典请求参数发送，则可以通过简单地省略 来绑定到对象@RequestParam，因此
public String content(RestDTO restDTO){...}
If you're sending json, you have to use @RequestBody.
如果您要发送json，则必须使用@RequestBody.
If whysoever you're insisting on the @RequestParam, note that you can bind multiple values against a map, so
如果您坚持使用@RequestParam，请注意您可以针对地图绑定多个值，因此
public String content(@RequestParam Map<String, String> restDTO){...}
From the @RequestParamdoc
If the method parameter is Map or MultiValueMap and a parameter name is not specified, then the map parameter is populated with all request parameter names and values.
如果方法参数是 Map 或 MultiValueMap 并且未指定参数名称，则使用所有请求参数名称和值填充 map 参数。
回答by Ken Bekov
You can't, because @RequestParamjust indicates, that onemethod's parameter should be bound to a oneweb request's parameter. It can't do mapping to objects. For use @RequestParamyou should change ajax request:
你不能，因为@RequestParam只是表明，一个方法的参数应该绑定到一个web 请求的参数。它不能映射到对象。要使用，@RequestParam您应该更改 ajax 请求：
var restDTO{
id: 3,
name: "hello"
}
$.ajax({
url: url,
type: 'POST',
data: restDTO,
success: function(data){
....
}
});
JQuery will send request as application/x-www-form-urlencodedand will process data to parameters automatically. You controller's method should look like following:
JQuery 将发送请求application/x-www-form-urlencoded并自动处理数据到参数。您的控制器方法应如下所示：
@RequestMapping("/url")
public String content(@RequestParam Long id, @RequestParam String name){...}
For automatically map parameters to object you can use @ModelAttributeannotation:
要自动将参数映射到对象，您可以使用@ModelAttribute注释：
@RequestMapping("/url")
public String content(@ModelAttribute RestDTO restDTO){...}
In this case, names in javascript map should match to names of properties in RestDTO.
在这种情况下，javascript 映射中的名称应与RestDTO.
Generally, @ModelAttributeand @RequestBodycreated for same purposes: for binding data from request to method (whether objects of primitive type).
通常，@ModelAttribute并且@RequestBody出于相同目的而创建：用于将数据从请求绑定到方法（无论是原始类型的对象）。
I consider, that @ModelAttributeis more convenient, when you working with html-forms and plain objects. There is ready to use Spring abilities like modelAttributeand path.
我认为，@ModelAttribute当您使用 html 表单和普通对象时，这更方便。有准备使用 Spring 能力，如modelAttribute和path。
In its turn, @RequestBodymore flexible, when you need manual control over data. Also, it is more convenient, when you're working with complex objects.
反过来，@RequestBody当您需要手动控制数据时，它会更加灵活。此外，当您处理复杂对象时，它更方便。
Personally me would prefer @RequestBodyand json.
我个人更喜欢@RequestBody和json。
回答by Alexandru Godri
In spring web you have these annotations:
在 spring web 中，您有这些注释：
RequestParam - used for get params (/path?name=)
RequestParam - 用于获取参数 (/path?name=)
PathVariable - used for path params (/path/{name})
PathVariable - 用于路径参数 (/path/{name})
RequestBody - used for post/put/patch etc. body
RequestBody - 用于 post/put/patch 等。 body
RequestHeader - for headers
RequestHeader - 用于标头
So you can't use RequestParam for post params, doesn't matter if json or not
所以你不能将 RequestParam 用于 post params，不管是否 json
