杰克逊序列化JAXB对象给出奇怪的结果

Question

I have a JAXB object. When I serialize it, the results are funny! Like this =>

{"formData":{
"preConditions":{
    "acceptTermsAndConditions":"<?xml version=\"1.0\" encoding=\"UTF-16\"?>\n<acceptTermsAndConditions>true</acceptTermsAndConditions>",
    "receivePromoEmail":"<?xml version=\"1.0\" encoding=\"UTF-16\"?>\n<receivePromoEmail>false</receivePromoEmail>"
}, etc...

Whereas, the source XML just has true and false as the values:-

  <formData>
    <preConditions>
      <acceptTermsAndConditions>true</acceptTermsAndConditions>
      <receivePromoEmail>false</receivePromoEmail>
    </preConditions> etc...

My code to generate the JSON is as follows:-

    Application application = (Application) JAXBUtil.getXMLAsApplication();
    ObjectMapper mapper = new ObjectMapper();
    AnnotationIntrospector introspector = new JaxbAnnotationIntrospector(TypeFactory.defaultInstance());
    // make deserializer use JAXB annotations (only)
    mapper.getDeserializationConfig().with(introspector);
    // make serializer use JAXB annotations (only)
    mapper.getSerializationConfig().with(introspector);


    try {
        mapper.writeValue(new File("application.json"), application);
    } catch (IOException e) {
        e.printStackTrace();
    }

Where the PreConditions class above is generated by JAXB2 (XJC). The following is a snippet:-

@XmlAccessorType(XmlAccessType.FIELD)
    @XmlType(name = "", propOrder = {
        "acceptTermsAndConditions",
        "receivePromoEmail"
    })
    public static class PreConditions {

        @XmlElement(required = true)
        protected Object acceptTermsAndConditions;
        @XmlElement(required = true)
        protected Object receivePromoEmail;

        /**
         * Gets the value of the acceptTermsAndConditions property.
         * 
         * @return
         *     possible object is
         *     {@link Object }
         *     
         */
        public Object getAcceptTermsAndConditions() {
            return acceptTermsAndConditions;
        }

        /**
         * Sets the value of the acceptTermsAndConditions property.
         * 
         * @param value
         *     allowed object is
         *     {@link Object }
         *     
         */
        public void setAcceptTermsAndConditions(Object value) {
            this.acceptTermsAndConditions = value;
        }

        /**
         * Gets the value of the receivePromoEmail property.
         * 
         * @return
         *     possible object is
         *     {@link Object }
         *     
         */
        public Object getReceivePromoEmail() {
            return receivePromoEmail;
        }

        /**
         * Sets the value of the receivePromoEmail property.
         * 
         * @param value
         *     allowed object is
         *     {@link Object }
         *     
         */
        public void setReceivePromoEmail(Object value) {
            this.receivePromoEmail = value;
        }

    }

Any clues on why the JSON is so crazy?

Answer 1

Since the nominal type for acceptTermsAndConditions is java.lang.Object , it is hard to know what exactly is going on. Serializer will be chosen based on runtime type on serialization -- my guess is that it would be DOM Document . On deserialization it would not work too well, and would just become java.util.Map .

So you may need to change the schema to generate more specific types: anything with java.lang.Object are likely to cause issues.

You may want to see actual Java types that your object has before serialization. That should explain where the strange output comes from. I don't think it can be simple boolean value.