无法从 START_OBJECT 令牌中反序列化 org.joda.time.DateTime 或 LocalDate 的实例

v2.1.1, 乔达模块。 https://github.com/FasterXML/jackson-datatype-joda

我可以使用 objectMapper.readValue(file, pojo .class); 在单元测试中将 json 文件转换为 pojo；

但是，当 Spring RESTTemplate 客户端调用默认 json 转换器 http://static.springsource.org/spring/docs/3.1.x/javadoc-api/org/springframework/http/converter/json/MappingJacksonHttpMessageConverter.html要转换包含具有 Joda 类型（DateTime 或 LocalDate）的域对象的 inputStream，它会生成错误：objectMapper.readValue(httpInputMessage.getBody(), javaType)

   
com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of org.joda.time.DateTime out of START_OBJECT token
at Source: org.mortbay.jetty.HttpParser$Input@46a09b; line: 1, column: 752
at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:164)
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:599)
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:593)
at com.fasterxml.jackson.datatype.joda.deser.DateTimeDeserializer.deserialize(DateTimeDeserializer.java:51)
at com.fasterxml.jackson.datatype.joda.deser.DateTimeDeserializer.deserialize(DateTimeDeserializer.java:21)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:375)
at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:559)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObjectUsingNonDefault(BeanDeserializer.java:393)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:289)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:121)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:226)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:203)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:23)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:375)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeSetAndReturn(MethodProperty.java:106)
at com.fasterxml.jackson.databind.deser.BuilderBasedDeserializer.deserializeFromObject(BuilderBasedDeserializer.java:326)
at com.fasterxml.jackson.databind.deser.BuilderBasedDeserializer.deserialize(BuilderBasedDeserializer.java:143)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:226)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:203)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:23)
at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:375)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeSetAndReturn(MethodProperty.java:106)
at com.fasterxml.jackson.databind.deser.BuilderBasedDeserializer.deserializeFromObject(BuilderBasedDeserializer.java:
  

LocalDate 也会出现同样的问题

com.fasterxml.jackson.databind.JsonMappingException: Unexpected token (START_OBJECT), expected START_ARRAY: expected JSON Array, String or Number
at Source: org.mortbay.jetty.HttpParser$Input@d297c0; line: 1, column: 51
at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:164)
at com.fasterxml.jackson.databind.DeserializationContext.wrongTokenException(DeserializationContext.java:692)
at com.fasterxml.jackson.datatype.joda.deser.LocalDateDeserializer.deserialize(LocalDateDeserializer.java:50)
....

  

为什么调用链在一种情况下传递 START_OBJECT 而在另一种情况下传递 START_ARRAY？

为了解决类似的问题，我做了以下操作，

我从下载了 jackson-datatype-joda-2.2.1.jarhttp://mvnrepository.com/artifact/com.fasterxml.jackson.datatype/jackson-datatype-joda/2.2.1 http://mvnrepository.com/artifact/com.fasterxml.jackson.datatype/jackson-datatype-joda/2.2.1如果您使用 Maven，依赖关系定义也在那里。

然后我为应用程序中的每个 LocalDate 字段添加了注释，如下所示：

@JsonDeserialize(using=LocalDateDeserializer.class)
private LocalDate releasedDate;

导入看起来像这样：

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.datatype.joda.deser.LocalDateDeserializer;

问题就消失了。

希望这可以帮助！