泽西+杰克逊反序列化失败与日期对象 [英] Jersey + Jackson deserialization failure with date object

问题描述

我正在使用jersey和jackson来开发我的REST API，并且在反序列化日期字符串时遇到问题。我在泽西岛注册了一个提供者类：

I'm using jersey and jackson together to develop my REST API, and I'm having a problem when deserializing a date string. I have register a provider class in Jersey:

@Provider
public class MyJsonProvider extends JacksonJsonProvider {
    public static final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
    @Override
    public void writeTo(Object value, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String,Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
        ObjectMapper mapper = locateMapper(type, mediaType);
        // Enable human readable date format
        SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
        mapper.getDeserializationConfig().setDateFormat(sdf);
        mapper.getSerializationConfig().setDateFormat(sdf);
        // Enable JAXB annotation, with Jackson annotation being the preferred one.
        AnnotationIntrospector primary = new JacksonAnnotationIntrospector();
        AnnotationIntrospector secondary = new JaxbAnnotationIntrospector();
        AnnotationIntrospector introspector = new AnnotationIntrospector.Pair(primary, secondary);
        mapper.getDeserializationConfig().setAnnotationIntrospector(introspector);
        mapper.getSerializationConfig().setAnnotationIntrospector(introspector);
        super.writeTo(value, type, genericType, annotations, mediaType, httpHeaders, entityStream);
    }
}

似乎泽西岛在启动时接了它：

And it seems like Jersey picked it up during start up:

Jan 24, 2011 2:53:23 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses
INFO: Provider classes found:
  class com.mypackage.MyJsonProvider

并且它工作正常序列化，但当我试图反序列化像 2010-01-25 00:00:00 这样的字符串时，我收到映射错误：

And it works fine for serialization, but when I tried to deserialize a string like 2010-01-25 00:00:00, I'm getting a mapping error:

SEVERE: Servlet.service() for servlet JerseyWebApplication threw exception
org.codehaus.jackson.map.JsonMappingException: Can not construct instance of java.util.Date from String value '2010-01-25 00:00:00': not a valid representation (error: Can not parse date "2010-01-25 00:00:00": not compatible with any of standard forms ("yyyy-MM-dd'T'HH:mm:ss.SSSZ", "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", "EEE, dd MMM yyyy HH:mm:ss zzz", "yyyy-MM-dd"))
 at [Source: org.apache.catalina.connector.CoyoteInputStream@6a3d899a; line: 3, column: 37]
    at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:159)
    at org.codehaus.jackson.map.deser.StdDeserializationContext.weirdStringException(StdDeserializationContext.java:222)
    at org.codehaus.jackson.map.deser.StdDeserializer._parseDate(StdDeserializer.java:283)
    at org.codehaus.jackson.map.deser.DateDeserializer.deserialize(DateDeserializer.java:26)
    at org.codehaus.jackson.map.deser.DateDeserializer.deserialize(DateDeserializer.java:17)
    at org.codehaus.jackson.map.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:135)
    at org.codehaus.jackson.map.deser.SettableBeanProperty$MethodProperty.deserializeAndSet(SettableBeanProperty.java:221)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:391)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:286)
    at org.codehaus.jackson.map.ObjectMapper._readValue(ObjectMapper.java:1568)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:788)
    at org.codehaus.jackson.jaxrs.JacksonJsonProvider.readFrom(JacksonJsonProvider.java:398)
    at com.sun.jersey.spi.container.ContainerRequest.getEntity(ContainerRequest.java:454)

似乎泽西岛仍在使用 JacksonJsonProvider 以某种方式处理反序列化。我不确定我做错了什么。我应该如何在球衣内配置杰克逊？谢谢！

It seems like Jersey is still using JacksonJsonProvider to handle the deserialization somehow. I'm not sure what I am doing wrong. How should I configure the jackson within jersey? Thanks!

推荐答案

super.writeTo方法再次调用locateMapper（type，mediaType）并创建mapper对象的新实例，以便映射器从不使用配置dateformat的对象。
您可以在调试模式下确认。

super.writeTo method calls locateMapper(type, mediaType) again and creates a new instance of mapper object so the mapper object on which you configure the dateformat is never used. You can confirm in debug mode.

您可以做的是通过创建构造函数来创建自己的映射器对象

What you can do is create your own mapper object by creating a constructor

 MyJsonProvider(){

     ObjectMapper mapper = new ObjectMapper();
    // Enable human readable date format
    SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
    mapper.getDeserializationConfig().setDateFormat(sdf);
    mapper.getSerializationConfig().setDateFormat(sdf);
    // Enable JAXB annotation, with Jackson annotation being the preferred one.
    AnnotationIntrospector primary = new JacksonAnnotationIntrospector();
    AnnotationIntrospector secondary = new JaxbAnnotationIntrospector();
    AnnotationIntrospector introspector = new AnnotationIntrospector.Pair(primary, secondary);
    mapper.getDeserializationConfig().setAnnotationIntrospector(introspector);
    mapper.getSerializationConfig().setAnnotationIntrospector(introspector);
   super(mapper);}

然后你不需要覆盖writeTo方法

Then you dont need to override the writeTo method

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