public static class NumberDeserializers.NumberDeserializer extends StdScalarDeserializer<Object>
Number.class, we can just rely on type
mappings that plain JsonParser.getNumberValue() returns.
There is one additional complication: some numeric
types (specifically, int/Integer and double/Double) are "non-typed";
meaning that they will NEVER be output with type information.
But other numeric types may need such type information.
This is why deserializeWithType(com.fasterxml.jackson.core.JsonParser, com.fasterxml.jackson.databind.DeserializationContext, com.fasterxml.jackson.databind.jsontype.TypeDeserializer) must be overridden.
JsonDeserializer.None| Modifier and Type | Field and Description |
|---|---|
static NumberDeserializers.NumberDeserializer |
instance |
_valueClass, F_MASK_ACCEPT_ARRAYS, F_MASK_INT_COERCIONS| Constructor and Description |
|---|
NumberDeserializer() |
| Modifier and Type | Method and Description |
|---|---|
Object |
deserialize(JsonParser p,
DeserializationContext ctxt)
Method that can be called to ask implementation to deserialize
JSON content into the value type this serializer handles.
|
Object |
deserializeWithType(JsonParser p,
DeserializationContext ctxt,
TypeDeserializer typeDeserializer)
As mentioned in class Javadoc, there is additional complexity in
handling potentially mixed type information here.
|
deserialize, getEmptyAccessPattern, getNullAccessPattern, supportsUpdate_byteOverflow, _coercedTypeDesc, _coerceEmptyString, _coerceIntegral, _coerceNullToken, _coerceTextualNull, _deserializeFromArray, _deserializeFromEmpty, _deserializeWrappedValue, _failDoubleToIntCoercion, _findNullProvider, _hasTextualNull, _intOverflow, _isEmptyOrTextualNull, _isIntNumber, _isNaN, _isNegInf, _isPosInf, _neitherNull, _nonNullNumber, _parseBooleanFromInt, _parseBooleanPrimitive, _parseBytePrimitive, _parseDate, _parseDate, _parseDateFromArray, _parseDoublePrimitive, _parseDoublePrimitive, _parseFloatPrimitive, _parseFloatPrimitive, _parseIntPrimitive, _parseIntPrimitive, _parseLongPrimitive, _parseLongPrimitive, _parseShortPrimitive, _parseString, _reportFailedNullCoerce, _shortOverflow, _verifyEndArrayForSingle, _verifyNullForPrimitive, _verifyNullForPrimitiveCoercion, _verifyNullForScalarCoercion, _verifyNumberForScalarCoercion, _verifyStringForScalarCoercion, findContentNullProvider, findContentNullStyle, findConvertingContentDeserializer, findDeserializer, findFormatFeature, findFormatOverrides, findValueNullProvider, getValueClass, getValueType, handledType, handleMissingEndArrayForSingle, handleUnknownProperty, isDefaultDeserializer, isDefaultKeyDeserializer, parseDoublefindBackReference, getDelegatee, getEmptyValue, getEmptyValue, getKnownPropertyNames, getNullValue, getNullValue, getObjectIdReader, isCachable, replaceDelegatee, unwrappingDeserializerpublic static final NumberDeserializers.NumberDeserializer instance
public Object deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
JsonDeserializerPre-condition for this method is that the parser points to the first event that is part of value to deserializer (and which is never JSON 'null' literal, more on this below): for simple types it may be the only value; and for structured types the Object start marker or a FIELD_NAME.
The two possible input conditions for structured types result from polymorphism via fields. In the ordinary case, Jackson calls this method when it has encountered an OBJECT_START, and the method implementation must advance to the next token to see the first field name. If the application configures polymorphism via a field, then the object looks like the following.
{
"@class": "class name",
...
}
Jackson consumes the two tokens (the @class field name
and its value) in order to learn the class and select the deserializer.
Thus, the stream is pointing to the FIELD_NAME for the first field
after the @class. Thus, if you want your method to work correctly
both with and without polymorphism, you must begin your method with:
if (p.getCurrentToken() == JsonToken.START_OBJECT) {
p.nextToken();
}
This results in the stream pointing to the field name, so that
the two conditions align.
Post-condition is that the parser will point to the last event that is part of deserialized value (or in case deserialization fails, event that was not recognized or usable, which may be the same event as the one it pointed to upon call).
Note that this method is never called for JSON null literal, and thus deserializers need (and should) not check for it.
deserialize in class JsonDeserializer<Object>p - Parsed used for reading JSON contentctxt - Context that can be used to access information about
this deserialization activity.IOExceptionpublic Object deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws IOException
deserializeWithType in class StdScalarDeserializer<Object>typeDeserializer - Deserializer to use for handling type informationIOExceptionCopyright © 2008–2018 FasterXML. All rights reserved.