如何正确解组JAX-RS Webservice响应（JSON数组）？ [英] How to unmarshall JAX-RS Webservice response (JSON Array) correctly?

问题描述

我有以下域名类：

  @XmlRootElement 
 public class User {
 
 private long id; 
私人字符串电子邮件; 
 private String forename; 
私人字符串角色; 
 $ b $ public User（）{
 // JAXB 
所需的值} 
 
 // + Getters + Setters 
} 
  

和以下资源类：

  @Produces（MediaType.APPLICATION_JSON）
 @Path（/ users）
 public class UserService {
 
 @GET 
 public User [] getUsers（）{
 User [] users = ... //来自DB 
的用户返回用户; 
 
 
 
 
 
 
如果我要求资源（/ users）以下的json响应：
 
 
  {
user：
 [
 {
id：1，
email：[e-mail]，
forename：Toby，
role：admin
} 
，
 {
id：2，
email：[e-mail]，
forename： Rob，
角色：开发者
} 
] 
} 
  
在客户端（我有相同的User.class），我想将这个JSON响应解组到相应的POJO。这意味着在这个例子中，我想获得两个类型的用户对象。我使用GSON做了一些实验性的东西，比如 
 
 
  User [] users = gson.fromJson（JSONString，User []。class）
  
但无法使其正常工作。例外： 
 
 
  JSONParseException：期望对象，但找到数组
  
任何人都可以告诉我Iam在这里做错了什么吗？或者是我的json格式的问题？
 
 
 
 编辑： 
使用自己的集合类型适配器实现前面提到的<  ：
  Type usersType = new TypeToken< List< User>>（）{} .getType（）; 
列表<用户> users = new ArrayList< User>（）; 
 users = gson.fromJson（reader，usersType）; 
  
现在Iam得到一个JsonParseException：
 
 <$ p JsonDeserializer无法反序列化Json Object {user：[{id：1，email：[e-mail]，forename：Toby ，.... 
  

解决方案

JSON响应！在此帖子的帮助下，我绕过了以Object-> XML-> JSON方式直接进行Object-> JSON转换，从而导致由gson解释的干净的JSON语法。将尽快用我的完整示例源更新答案。

I have some problem using Jersey REST webservices.

I have the following domain class:

@XmlRootElement
public class User {

    private long id;
    private String email;
    private String forename;
    private String role;

    public User() {
        // required for JAXB
    }

    // + Getters + Setters
}

and the following resource class:

@Produces(MediaType.APPLICATION_JSON)
@Path("/users")
public class UserService {

    @GET
    public User[] getUsers() {
        User[] users = ... // Users from DB 
        return users;
    }
}

If I request that resource (/users) I get the following json response:

{
 "user":  
 [
  {
   "id":"1",
   "email":"[e-mail]",
   "forename":"Toby",
   "role":"admin"
  }
 ,
  {
   "id":"2",
   "email":"[e-mail]",
   "forename":"Rob",
   "role":"developer"
  }
 ]
}

On the client side (where I have the same User.class) I want to unmarshall this JSON response back to the corresponding POJOs. That means in this example I would like to get two Object of type User. I did some experimental stuff with GSON like

User[] users = gson.fromJson(JSONString, User[].class)

but was not able to get it working. Exception:

JSONParseException: Expecting object but found array

Can anyone tell me what Iam doing wrong here? Or is my json format the problem?

Edit: Tried it with an own implementation of a collection type adapter as mentioned here:

Type usersType = new TypeToken<List<User>>() {}.getType();
List<User> users = new ArrayList<User>();
users = gson.fromJson(reader, usersType);

Now Iam getting an JsonParseException:

The JsonDeserializer failed to deserialize Json Object {"user":[{"id":"1","email":"[e-mail]","forename":"Toby",....

解决方案

it really was the format of the json response! with the help of this post I bypassed the Object->XML->JSON way to a direct Object->JSON transformation which leads to a clean JSON syntax interpretable by gson. will update the answer with my full example source soon.

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