java - jackson :UnrecognisedPropertyException

我有以下课程：

LocationCustomDataItem.java

public class LocationCustomDataItem {

private String attributeNumber;
private String attributeLabel;
private String attributeValue;

public LocationCustomDataItem() {

}

public LocationCustomDataItem(final String attributeNumber, final String attributeLabel, final String attributeValue) {
    this.attributeNumber = attributeNumber;
    this.attributeLabel = attributeLabel;
    this.attributeValue = attributeValue;
}
/**
 * @return the attributeNumber
 */
public String getAttributeNumber() {
    return attributeNumber;
}
/**
 * @param attributeNumber the attributeNumber to set
 */
public void setAttributeNumber(String attributeNumber) {
    this.attributeNumber = attributeNumber;
}
/**
 * @return the attributeLabel
 */
public String getAttributeLabel() {
    return attributeLabel;
}
/**
 * @param attributeLabel the attributeLabel to set
 */
public void setAttributeLabel(String attributeLabel) {
    this.attributeLabel = attributeLabel;
}
/**
 * @return the attributeValue
 */
public String getAttributeValue() {
    return attributeValue;
}
/**
 * @param attributeValue the attributeValue to set
 */
public void setAttributeValue(String attributeValue) {
    this.attributeValue = attributeValue;
}

@Override
public int hashCode() {
    return HashCodeBuilder.reflectionHashCode(this, false);
}

@Override
public boolean equals(Object obj) {
    return EqualsBuilder.reflectionEquals(this, obj);
}

@Override
public String toString() {
    return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE, false);
}

LocationCustomDataAttributes.java

public class LocationCustomDataAttributes {

private final List<LocationCustomDataItem> locationCustomDataItems;

public LocationCustomDataAttributes() {
    this.locationCustomDataItems = new ArrayList<>();
}

public LocationCustomDataAttributes(final List<LocationCustomDataItem> locationCustomDataItems) {
    this.locationCustomDataItems = locationCustomDataItems;
}

/**
 * @return unmodifiable locationCustomDataItems list
 */
public List<LocationCustomDataItem> getLocationCustomDataItems() {
    return Collections.unmodifiableList(this.locationCustomDataItems);
}

/**
 * Adds LocationCustoDataItem to internal collection
 *
 * @param item LocationCustomDataItem to add to item list
 */
public void addItem(final LocationCustomDataItem item) {
    this.locationCustomDataItems.add(item);
}


@Override
public int hashCode() {
    return HashCodeBuilder.reflectionHashCode(this, false);
}

@Override
public boolean equals(Object obj) {
    return EqualsBuilder.reflectionEquals(this, obj);
}

@Override
public String toString() {
    return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE, false);
}

和这个测试JSON：

{
   "locationCustomDataAttributes" : {
      "locationCustomDataItems" : [ {
         "attributeLabel" : "testLabel1",
         "attributeNumber" : "testNumber1",
         "attributeValue" : "testLabel1"
      }, {
         "attributeLabel" : "testLabel2",
         "attributeNumber" : "testNumber2",
         "attributeValue" : "testLabel2"
      } ]
   }
}

我正在尝试使用ObjectMapper将json转换为对象，但是它在“ locationCustomDataAttributes”周围引发了unrecognisedPropertyException：

MapperTest.java

@Test
public void test() throws JsonParseException, JsonMappingException, IOException {
    ObjectMapper om =new ObjectMapper();

    LocationCustomDataAttributes actual = om.readValue(json, LocationCustomDataAttributes.class);

    LocationCustomDataAttributes expected = new LocationCustomDataAttributes();
    expected.addItem(new LocationCustomDataItem("testNumber1", "testLabel1", "testValue1"));
    expected.addItem(new LocationCustomDataItem("testNumber2", "testLabel2", "testValue2"));

    assertThat(actual).isEqualTo(expected);
}

错误信息：

com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "locationCustomDataAttributes" (class com.lmig.ci.fnol.transformer.domain.LocationCustomDataAttributes), not marked as ignorable (one known property: "locationCustomDataItems"])
 at [Source: {"locationCustomDataAttributes" : {"locationCustomDataItems" : [ {"attributeLabel" : "testLabel1","attributeNumber" : "testNumber1","attributeValue" : "testLabel1"},{"attributeLabel" : "testLabel2","attributeNumber" : "testNumber2","attributeValue" : "testLabel2"}]}}; line: 1, column: 36] (through reference chain: com.lmig.ci.fnol.transformer.domain.LocationCustomDataAttributes["locationCustomDataAttributes"])
at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:62)
at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:833)
at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1096)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1467)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1445)

//等...`

我没有直接与Jackson一起工作的大量经验，因此我还没有对类本身进行注释，但是经过先前的努力（例如使用Spring控制器），转换会自动发生，而无需在类上进行注释。在这种情况下，类中缺少了什么？或者当前的类结构由于某种原因而无法自动进行杰克逊的自动转换吗？

最佳答案

om.readValue(json, LocationCustomDataAttributes.class)

此行要求解析JSON文档中的LocationCustomDataAttributes对象。但是JSON实际上包含一个包装器对象，该对象具有可以解析为LocationCustomDataAttributes对象的属性。解决方案：


创建包装对象的阅读器。例如。

ObjectReader reader = om
    .readerFor(LocationCustomDataAttributes.class)
    .withRootName("locationCustomDataAttributes");
LocationCustomDataAttributes actual = reader.readValue(json);

定义包装器类

class AttributesWrapper {
    private LocationCustomDataAttributes locationCustomDataAttributes;
    // add getters, setters, constructors etc
}

然后解析它：

LocationCustomDataAttributes actual = om
    .readValue(json, AttributesWrapper.class)
    .getLocationCustomDataAttributes();