[英]Jackson XML deserialization of abstract type results in fields with null values
当尝试将 XML 反序列化为扩展抽象基 class 的 object 时,我看到引用列表包含预期数量的元素,但这些对象上的所有字段都是 null。
仅当我为抽象 class 创建一个 XML 读取器时才会发生这种情况。如果我直接反序列化为具体实现,则所有字段都具有预期值。
我在下面添加了最低限度的工作示例
预期为 output(作为 json 以提高可读性)
{
"References": [ { "id": "1", "Type": "Secondary Image" } ]
}
实际 output(作为 json 以提高可读性)
{
"References": [ { "id": null, "Type": null } ]
}
测试数据
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Foo TypeID="ConcreteA">
<Reference ID="1" Type="Secondary Image">
<Values/>
</Reference>
</Foo>
摘要基地 class
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "TypeID", visible = true)
@JsonSubTypes({
@JsonSubTypes.Type(value = ConcreteClassA.class, name = "ConcreteA")
})
public abstract class AbstractBase {
@JacksonXmlProperty(localName = "TypeID", isAttribute = true)
private String typeId;
@JsonIgnore
private List<Reference> references = new ArrayList<>();
@JacksonXmlElementWrapper(useWrapping = false)
@JacksonXmlProperty(localName = "Reference")
public List<Reference> getReferences() {
return references;
}
@JsonSetter
public AbstractBase setReferences(List<Reference> references) {
this.references.addAll(references);
return this;
}
}
具体实施
public class ConcreteClassA extends AbstractBase {}
测试用例
public class DeserializationTest {
@Test
public void deserializedAbstractClass_fieldsShouldNotBeNull() throws JsonProcessingException {
var mapper = new XmlMapper()
.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true)
.deactivateDefaultTyping()
.registerModule(new JacksonXmlModule());
var xmlData = readTestData();
var reader = mapper.readerFor(AbstractBase.class);
var deserializedObject = reader.readValue(xmlData);
assert(deserializedObject instanceof ConcreteClassA);
var concreteClassA = (ConcreteClassA) deserializedObject;
assert(concreteClassA.getReferences().get(0).getId() != null);
}
@Test
public void deserializedConcreteClass_fieldsShouldNotBeNull() throws JsonProcessingException {
var mapper = new XmlMapper()
.configure(MapperFeature.ACCEPT_CASE_INSENSITIVE_PROPERTIES, true)
.configure(MapperFeature.USE_BASE_TYPE_AS_DEFAULT_IMPL, true)
.registerModule(new JacksonXmlModule());
var xmlData = readTestData();
var reader = mapper.readerFor(ConcreteClassA.class);
var deserializedObject = reader.readValue(xmlData);
assert(deserializedObject instanceof ConcreteClassA);
var concreteClassA = (ConcreteClassA) deserializedObject;
assert(concreteClassA.getReferences().get(0).getId() != null);
}
private String readTestData() {
try {
var datafile = getClass().getClassLoader().getResource("TestData.xml");
return Files.lines(Paths.get(datafile.toURI())).collect(Collectors.joining());
} catch (Exception e) { return ""; }
}
}
事实证明,我已经设法解决了多个问题。
此问题已通过升级到 2.12 得到解决,这意味着不再需要执行此操作来处理展开的元素。
我通过让 setter 接受单个元素,然后将其添加到列表中来解决这个问题
@JsonSetter(value = "Reference")
public AbstractBase setReferences(Reference reference) {
this.references.add(references);
return this;
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.