Java 模型的 JSON 字段映射

JSON field mapping for Java model

提问by sergionni

JSON which is sent:

发送的 JSON：

{
  "Banner": "ABC"
}

Java model:

Java模型：

...
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class BannerData implements java.io.Serializable {

    private static final long serialVersionUID = 5664846645733319592L;

    @JsonProperty(value = "Banner")
    private String banner;

    public String getBanner() {
        return banner;
    }

    public void setBanner(String banner) {
        this.banner = banner;
    }
}

Controller:

控制器：

@RequestMapping(value = {"/GetBanner"}, method = RequestMethod.POST)
@ResponseBody
public ResponseEntity<String> enrollCustomer(@RequestBody BannerData body, HttpServletRequest request) throws Exception {
...
}

request to /GetBannerreturns:
The request sent by the client was syntactically incorrect.

请求/GetBanner返回：
客户端发送的请求在语法上不正确。

Works OKwhen json changed to (lowercase naming as is Java field name):

工程确定当JSON变更为（小写字母命名的就是Java字段名）：

{
  "banner": "ABC"
}

However I need uppercasefield naming in JSON.
Looks like @JsonProperty(value = "Banner")does not work.

但是我需要JSON 中的大写字段命名。 看起来不起作用。
@JsonProperty(value = "Banner")

Is it correct mapping?

它是正确的映射吗？

采纳答案by Arthur Eirich

Maybe you just try to:

也许你只是尝试：

@JsonProperty("Banner")

without 'value ='. I used it in my project and it actually worked as expected.

没有“值=”。我在我的项目中使用了它，它实际上按预期工作。

UPDATE

更新

I just created some test classes to test the bahaviour of your problem. What I have done:

我刚刚创建了一些测试类来测试您的问题的行为。我做了什么：

import org.codehaus.Hymanson.annotate.JsonIgnoreProperties;
import org.codehaus.Hymanson.annotate.JsonProperty;
import org.codehaus.Hymanson.map.annotate.JsonSerialize;


@JsonIgnoreProperties(ignoreUnknown = true)
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class BannerData implements java.io.Serializable {

 private static final long serialVersionUID = 5664846645733319592L;

 @JsonProperty("Banner")
 private String banner;

 public String getBanner() {
     return banner;
 }

 public void setBanner(String banner) {
     this.banner = banner;
 }
}

Another class to read the json:

另一个读取json的类：

import org.codehaus.Hymanson.map.ObjectMapper;
import java.io.File;
import java.io.IOException;

public class BannerReader {
 private static final String JSON_PATH = "pathToYourJson";

 public BannerData readBanner() throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    return mapper.readValue(new File(JSON_PATH), BannerData.class);
 }
}

And finally the entry point class:

最后是入口点类：

import java.io.IOException;

public class BannerTest {

 public static void main(String[] args) throws IOException {
     BannerReader reader = new BannerReader();
     BannerData bannerData = reader.readBanner();
     System.out.println(bannerData.getBanner());
 }
}

prints:

印刷：

ABC

Used dependency:

使用的依赖：

<dependency>
  <groupId>org.codehaus.Hymanson</groupId>
  <artifactId>Hymanson-mapper-asl</artifactId>
  <version>1.9.13</version>
</dependency>

json file:

json文件：

{
  "Banner": "ABC"
}

UPDATE 2

更新 2

While the above code does not work for you, try adding

虽然上面的代码对您不起作用，请尝试添加

@JsonProperty("Banner")

not only to the private variable, but also to the getter/setter pair, like:

不仅是私有变量，还有 getter/setter 对，比如：

@JsonProperty("Banner")
private String banner;

@JsonProperty("Banner")
public String getBanner() {
  return banner;
}

@JsonProperty("Banner")
public void setBanner(String banner) {
  this.banner = banner;
}

回答by Ashish Patil

I would suggest below; (If you are using ObjectMapper)

我会在下面建议; （如果您使用的是 ObjectMapper）

once you get your ObjectMapper, you can set PropertyNamingStrategy with PascalCase. this is link for documentation

获得 ObjectMapper 后，您可以使用 PascalCase 设置 PropertyNamingStrategy。这是文档的链接

ObjectMapper mapper = new ObjectMapper();
mapper.setPropertyNamingStrategy(
    PropertyNamingStrategy.PascalCaseStrategy);

If you are not using ObjectMapper- then Annotate your BannerDataclass with @JsonNaminglike below--

如果您不使用 ObjectMapper- 然后BannerData使用@JsonNaming如下注释您的类-

@JsonNaming(PropertyNamingStrategy.LowerCaseWithUnderscoresStrategy.class) 
public class BannerData implements java.io.Serializable {

I found out @JsonNaming here in github

我在 github 中发现了 @JsonNaming

回答by Shaun

Try it on the getter

在吸气剂上试试

@JsonProperty(value = "Banner")
public String getBanner() {

EDIT:

编辑：

Show us your Spring config file. Are you really using Hymanson? See http://www.journaldev.com/2552/spring-restful-web-service-example-with-json-Hymanson-and-client-program

向我们展示您的 Spring 配置文件。你真的在用Hyman逊吗？见http://www.journaldev.com/2552/spring-restful-web-service-example-with-json-Hymanson-and-client-program

 <!-- Configure to plugin JSON as request and response in method handler -->
 <beans:bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
     <beans:property name="messageConverters">
         <beans:list>
             <beans:ref bean="jsonMessageConverter"/>
         </beans:list>
     </beans:property>
 </beans:bean>

 <!-- Configure bean to convert JSON to POJO and vice versa -->
 <beans:bean id="jsonMessageConverter" class="org.springframework.http.converter.json.MappingHymanson2HttpMessageConverter">
 </beans:bean> 

EDIT 2

编辑 2

Since you may or may not be using Hymanson... try some other annotations @XmlElement(name="Banner")

由于您可能会或可能不会使用 Hymanson ... 尝试一些其他注释 @XmlElement(name="Banner")

From GSON perhaps @SerializedName("Banner")

也许来自 GSON @SerializedName("Banner")

回答by pkozlov

Have you tried to update your Hymanson from 1.9.13 to 2.5.4 (it has another artifact group id - com.fasterxml.Hymanson )

您是否尝试将 Hymanson 从 1.9.13 更新到 2.5.4（它有另一个工件组 ID - com.fasterxml.Hymanson ）

Is this code works correctly for you?

此代码是否适合您？

ObjectMapper mapper = new ObjectMapper();
BannerData bannerData = mapper.readValue("{ \"Banner\": \"ABC\"}", BannerData.class);

Works fine with me (If I replace "Banner" with "banner" - got wrong object with null "banner" field.)

对我来说很好用（如果我用“横幅”替换“横幅” - 用空的“横幅”字段得到错误的对象。）

Also this code can be useful:

此代码也很有用：

System.out.println(mapper.getDeserializationConfig().getPropertyNamingStrategy());

Something can be wrong with property naming strategy - if you use custom one.

属性命名策略可能有问题 - 如果您使用自定义策略。