Spring MVC @RequestParam 对象列表
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Spring MVC @RequestParam a list of objects
提问by Kingamere
I want to create a page where a person sees a list of users and there are check boxes next to each of them that the person can click to have them deleted.
我想创建一个页面，其中一个人可以看到一个用户列表，并且每个人旁边都有复选框，该人可以单击以将其删除。
In my MVC that consumes a REST API, I want to send a List of Userobjects to the REST API.
在我使用 REST API 的 MVC 中，我想向 REST API 发送一个User对象列表。
Can the @RequestParamannotation support that?
在可@RequestParam注解支持？
For example:
例如：
@RequestMapping(method = RequestMethod.DELETE, value = "/delete")
public @ResponseBody Integer delete(
@RequestParam("users") List<Users> list) {
Integer deleteCount = 0;
for (User u : list) {
if (u != null) {
repo.delete(u);
++deleteCount;
}
}
return deleteCount;
}
In the MVC client, the url would be:
在 MVC 客户端中，url 将是：
List list = new ArrayList<User>();
....
String url = "http://restapi/delete?users=" + list;
回答by Mathias Dpunkt
Request parameters are a Multimap of String to String. You cannot pass a complex object as request param.
请求参数是字符串到字符串的 Multimap。您不能将复杂对象作为请求参数传递。
But if you just pass the username that should work - see how to capture multiple parameters using @RequestParam using spring mvc?
但是，如果您只是传递应该有效的用户名 - 看看如何使用 spring mvc 使用@RequestParam 捕获多个参数？
@RequestParam("users") List<String> list
@RequestParam("users") List<String> list
But I think it would be better to just use the request body to pass information.
但我认为最好只使用请求正文来传递信息。
回答by Warkst
Though this question has been answered and the answer has been accepted, I found that using @RequestBodyinstead of @RequestParamdoes exactly what you want, plus it's very easy.
虽然这个问题已经得到回答并且答案已经被接受，但我发现使用@RequestBody而不是@RequestParam完全符合你的要求，而且它很容易。
You'd end up with @RequestBody List<Integer> list.
You can call your web service with an HTTP request (POSTwill definitely work, but DELETEshould work too) with request body: [id1, id2, ...]. If it doesn't work out of the box like that, try adding consumes = MediaType.APPLICATION_JSON_VALUE)to the @RequestMapping.
你最终会得到@RequestBody List<Integer> list. 您可以使用 HTTP 请求（POST肯定会工作，但也DELETE应该工作）使用 request body:调用您的 Web 服务[id1, id2, ...]。如果它不能像那样开箱即用，请尝试添加consumes = MediaType.APPLICATION_JSON_VALUE)到@RequestMapping.
回答by Frank.Chang
Spring mvc can support List<Object>, Set<Object>and Map<Object>param, but without @RequestParam.
Spring mvc 可以支持List<Object>,Set<Object>和Map<Object>param，但不支持 @RequestParam。
Take List<Object>as example, if your object is User.java, and it like this:
以List<Object>为例，如果你的目标是User.java，它是这样的：
public class User {
private String name;
private int age;
// getter and setter
}
And you want pass a param of List<User>, you can use url like this
并且你想传递一个参数List<User>，你可以像这样使用 url
http://127.0.0.1:8080/list?users[0].name=Alice&users[0].age=26&users[1].name=Bob&users[1].age=16
Remember to encode the url, the url after encoded is like this:
记得对url进行编码，编码后的url是这样的：
http://127.0.0.1:8080/list?users%5B0%5D.name=Alice&users%5B0%5D.age=26&users%5B1%5D.name=Bob&users%5B1%5D.age=16
Example of List<Object>, Set<Object>and Map<Object>is displayed in my github.
的示例List<Object>，Set<Object>并Map<Object>显示在我的 github 中。
