杰克逊xml和json根元素

Question

我有一个服务，可以返回JSON和XML格式的对象。

http://localhost:8091/apiN/xml/2

XML结果

<restObjectList>
    <restObjectList>
        <restObjectList>
            <timestamp>2017-06-19 17:01:01</timestamp>
            <title>Rest object</title>
            <fullText>This is the full text. ID: 1</fullText>
            <id>1</id>
            <value>0.1412789210135622</value>
        </restObjectList>
        <restObjectList>
            <timestamp>2017-06-19 17:01:01</timestamp>
            <title>Rest object</title>
            <fullText>This is the full text. ID: 2</fullText>
            <id>2</id>
            <value>0.9886539664938628</value>
        </restObjectList>
    </restObjectList>
</restObjectList>

http://localhost:8091/apiN/2

JSON结果

{
    "restObjectList": [
        {
            "timestamp": "2017-06-19 17:01:01",
            "title": "Rest object",
            "fullText": "This is the full text. ID: 1",
            "id": 1,
            "value": 0.1412789210135622
        },
        {
            "timestamp": "2017-06-19 17:01:01",
            "title": "Rest object",
            "fullText": "This is the full text. ID: 2",
            "id": 2,
            "value": 0.9886539664938628
        }
    ]
}

我想要收到的结果

XML

<restObjectList>
    <restObject>
        <timestamp>2017-06-19 17:01:01</timestamp>
        <title>Rest object</title>
        <fullText>This is the full text. ID: 1</fullText>
        <id>1</id>
        <value>0.1412789210135622</value>
    </restObject>
    <restObject>
        <timestamp>2017-06-19 17:01:01</timestamp>
        <title>Rest object</title>
        <fullText>This is the full text. ID: 2</fullText>
        <id>2</id>
        <value>0.9886539664938628</value>
    </restObject>
</restObjectList>

json

{
    "restObjectList": [{
        "restObject": {
            "timestamp": "2017-06-19 17:01:01",
            "title": "Rest object",
            "fullText": "This is the full text. ID: 1",
            "id": 1,
            "value": 0.1412789210135622
        }
    }, {
        "restObject": {
            "timestamp": "2017-06-19 17:01:01",
            "title": "Rest object",
            "fullText": "This is the full text. ID: 2",
            "id": 2,
            "value": 0.9886539664938628
        }
    }]
}

如何将restObject转换为JSON和XML，并修复restObjectList的XML数据，因为该标记在不同级别上重复。

我的代码

RestObject

@JsonRootName(value = "restObject")
@XmlRootElement(name = "restObject")
public class RestObject implements Serializable {

    private LocalDateTime timestamp;
    private String title;
    private String fullText;
    private Long id;
    private Double value;

    //Getters, setters
}

RestObjectList

@JsonRootName(value = "restObjectList")
@XmlSeeAlso({RestObject.class})
public class RestObjectList {

    private List<RestObject> restObjectList;

    //Getter and setter
}

Jackson 配置

@Configuration
public class JacksonConfig {

    @Bean
    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(true).build();
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);//Use custom date-time format.
        objectMapper.configure(SerializationFeature.WRAP_ROOT_VALUE, false);
        objectMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, false);
        return objectMapper;
    }

    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.enable(SerializationFeature.WRAP_ROOT_VALUE);
        objectMapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE);
        return objectMapper;
    }
}

- Yan Khonski

Answer 1

JSON和XML结构不相同。在XML中，您需要一个RestObject列表，而在JSON中，您需要一个包装RestObject实例的元素列表。这不是一个简单的Jackson注释可以解决的问题，您需要一个专门为JSON序列化定制的自定义序列化器。首先，获取所需的XML格式很简单：

class RestObject implements Serializable {
    private LocalDateTime timestamp;
    private String title;
    private String fullText;
    private Long id;
    private Double value;
}

@JsonRootName("restObjectList")
class RestObjectList {
    @JacksonXmlProperty(localName = "restObject")
    @JacksonXmlElementWrapper(useWrapping = false)
    private List<RestObject> restObjectList;
}

如果您想将数组中的每个元素都包装在json中，您需要一个自定义序列化器，例如：

class RestObjectSerializer extends JsonSerializer<RestObject> {
    @Override
    public void serialize(RestObject value, JsonGenerator gen, SerializerProvider serializers) throws
            IOException {
        gen.writeStartObject();
        gen.writeObjectFieldStart("restObject");
        gen.writeObjectField("timeStamp", value.getTimestamp());
        gen.writeStringField("title", value.getTitle());
        // other fields
        gen.writeEndObject();
        gen.writeEndObject();
    }
}

仅使用能够将JSON序列化的ObjectMapper进行注册，以避免干扰XML序列化：

ObjectMapper mapper = new ObjectMapper();
SimpleModule module = new SimpleModule("MyModule");
module.addSerializer(RestObject.class, new RestObjectSerializer());
mapper.registerModule(module);

- Manos Nikolaidis