相当于@JsonIgnore,但仅适用于使用Jackson的xml字段/属性转换

Question

我有一个类,我使用Jackson对JSON,XML进行序列化/反序列化.

public class User {
    Integer userId;
    String name;
    Integer groupId;
...
}

我想在进行xml处理时忽略groupId,所以我的XML不会包含它:

<User>
 <userId>...</userId>
 <name>...</name>
</User>

但是JSON会:

{
  "userId":"...",
  "name":"...",
  "groupId":"..."
}

我知道@JsonIgnore可以兼用,但我只想在xml中忽略它.

我知道可用于执行此操作的混合注释(/sf/answers/1603477641/),但我认为应该有一个简单的注释来执行此操作,但无法找到它.杰克逊的文档(至少对我而言)并不像我想要找到这些东西时那样好.

Answer 1

杰克逊不支持开箱即用.但是您可以使用Jackson json视图或创建自定义注释,该注释将@JsonIgnore通过注释interospector为XML映射器进行解释.

这是一个例子:

public class JacksonXmlAnnotation {
    @Retention(RetentionPolicy.RUNTIME)
    public static @interface JsonOnly {
    }

    @JacksonXmlRootElement(localName = "root")
    public static class User {
        public final Integer userId;
        public final String name;
        @JsonOnly
        public final Integer groupId;

        public User(Integer userId, String name, Integer groupId) {
            this.userId = userId;
            this.name = name;
            this.groupId = groupId;
        }
    }

    public static class XmlAnnotationIntrospector extends JacksonXmlAnnotationIntrospector {
        @Override
        public boolean hasIgnoreMarker(AnnotatedMember m) {
            return m.hasAnnotation(JsonOnly.class) || super.hasIgnoreMarker(m);
        }
    }

    public static void main(String[] args) throws JsonProcessingException {
        User user = new User(1, "John", 23);
        XmlMapper xmlMapper = new XmlMapper();
        xmlMapper.setAnnotationIntrospector(new XmlAnnotationIntrospector());
        ObjectMapper jsonMapper = new ObjectMapper();
        System.out.println(xmlMapper.writerWithDefaultPrettyPrinter().writeValueAsString(user));
        System.out.println(jsonMapper.writerWithDefaultPrettyPrinter().writeValueAsString(user));
    }
}

输出:

<root>
  <userId>1</userId>
  <name>John</name>
</root>
{
  "userId" : 1,
  "name" : "John",
  "groupId" : 23
}