com.fasterxml.jackson.core.JsonGenerator#setCurrentValue ( )源码实例Demo

@Override
public void serializeWithType(Object bean, JsonGenerator gen,
        SerializerProvider provider, TypeSerializer typeSer)
    throws IOException
{
    /* 10-Dec-2014, tatu: Not sure if this can be made to work reliably;
     *   but for sure delegating to default implementation will not work. So:
     */
    if (_objectIdWriter != null) {
        _serializeWithObjectId(bean, gen, provider, typeSer);
        return;
    }
    gen.setCurrentValue(bean);
    WritableTypeId typeIdDef = _typeIdDef(typeSer, bean, JsonToken.START_ARRAY);
    typeSer.writeTypePrefix(gen, typeIdDef);
    serializeAsArray(bean, gen, provider);
    typeSer.writeTypeSuffix(gen, typeIdDef);
}
 

/**
 * Main serialization method that will delegate actual output to
 * configured
 * {@link BeanPropertyWriter} instances.
 */
@Override
public final void serialize(Object bean, JsonGenerator gen, SerializerProvider provider)
    throws IOException
{
    if (provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED)
            && hasSingleElement(provider)) {
        serializeAsArray(bean, gen, provider);
        return;
    }
    /* note: it is assumed here that limitations (type id, object id,
     * any getter, filtering) have already been checked; so code here
     * is trivial.
     */
    gen.writeStartArray();
    // [databind#631]: Assign current value, to be accessible by custom serializers
    gen.setCurrentValue(bean);
    serializeAsArray(bean, gen, provider);
    gen.writeEndArray();
}
 

@Override
public void serializeWithType(Object bean, JsonGenerator gen, SerializerProvider provider,
		TypeSerializer typeSer) throws IOException
{
    if (provider.isEnabled(SerializationFeature.FAIL_ON_UNWRAPPED_TYPE_IDENTIFIERS)) {
        provider.reportBadDefinition(handledType(),
                "Unwrapped property requires use of type information: cannot serialize without disabling `SerializationFeature.FAIL_ON_UNWRAPPED_TYPE_IDENTIFIERS`");
    }
    gen.setCurrentValue(bean); // [databind#631]
    if (_objectIdWriter != null) {
        _serializeWithObjectId(bean, gen, provider, typeSer);
        return;
    }
    if (_propertyFilterId != null) {
        serializeFieldsFiltered(bean, gen, provider);
    } else {
        serializeFields(bean, gen, provider);
    }
}
 

/**
 * Main serialization method that will delegate actual output to
 * configured
 * {@link BeanPropertyWriter} instances.
 */
@Override
public final void serialize(Object bean, JsonGenerator gen, SerializerProvider provider)
    throws IOException
{
    if (_objectIdWriter != null) {
        gen.setCurrentValue(bean); // [databind#631]
        _serializeWithObjectId(bean, gen, provider, true);
        return;
    }
    gen.writeStartObject(bean);
    if (_propertyFilterId != null) {
        serializeFieldsFiltered(bean, gen, provider);
    } else {
        serializeFields(bean, gen, provider);
    }
    gen.writeEndObject();
}
 

@Override
public void serializeWithType(
        CharIterable value,
        JsonGenerator g,
        SerializerProvider ctxt,
        TypeSerializer typeSer
) throws IOException {
    g.setCurrentValue(value);
    WritableTypeId typeIdDef;
    if (ctxt.isEnabled(SerializationFeature.WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS)) {
        typeIdDef = typeSer.writeTypePrefix(g, ctxt, typeSer.typeId(value, JsonToken.START_ARRAY));
        writeContentsAsArray(value, g);
    } else {
        typeIdDef = typeSer.writeTypePrefix(g, ctxt, typeSer.typeId(value, JsonToken.VALUE_STRING));
        char[] chars = value.toArray();
        g.writeString(chars, 0, chars.length);
    }
    typeSer.writeTypeSuffix(g, ctxt, typeIdDef);
}
 

@Override
public void serializeWithType(Map.Entry<?, ?> value, JsonGenerator g,
        SerializerProvider provider, TypeSerializer typeSer) throws IOException
{
    // [databind#631]: Assign current value, to be accessible by custom serializers
    g.setCurrentValue(value);
    WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
            typeSer.typeId(value, JsonToken.START_OBJECT));
    serializeDynamic(value, g, provider);
    typeSer.writeTypeSuffix(g, typeIdDef);
}
 

/**
 * Main serialization method that will delegate actual output to
 * configured
 * {@link BeanPropertyWriter} instances.
 */
@Override
public final void serialize(Object bean, JsonGenerator gen, SerializerProvider provider) throws IOException
{
    gen.setCurrentValue(bean); // [databind#631]
    if (_objectIdWriter != null) {
        _serializeWithObjectId(bean, gen, provider, false);
        return;
    }
    if (_propertyFilterId != null) {
        serializeFieldsFiltered(bean, gen, provider);
    } else {
        serializeFields(bean, gen, provider);
    }
}
 

@SuppressWarnings("rawtypes")
@Override
public JsonSerializer<?> findArraySerializer(SerializationConfig config, ArrayType type, BeanDescription beanDesc, TypeSerializer elementTypeSerializer,
    JsonSerializer<Object> elementValueSerializer) {

  Class<?> contentClass = type.getContentType().getRawClass();
  TypeCustomizationFactory factory = provider.factoryForArrayOf(contentClass);

  if (factory != null) {
    final JsonSerializer ser = factory.createSerializer();
    return new JsonSerializer() {

      @SuppressWarnings("unchecked")
      @Override
      public void serialize(Object o, JsonGenerator gen, SerializerProvider serializerProvider)
          throws IOException {

        gen.writeStartArray();
        gen.setCurrentValue(o);

        int length = Array.getLength(o);
        for (int i = 0; i < length; i++) {
          Object arrayElement = Array.get(o, i);
          ser.serialize(arrayElement, gen, serializerProvider);
        }

        gen.writeEndArray();
      }
    };
  }

  return super.findArraySerializer(config, type, beanDesc, elementTypeSerializer, elementValueSerializer);
}
 

@Override
public void serialize(T value, JsonGenerator gen, SerializerProvider provider) throws IOException {

    JsonStreamContext context = gen.getOutputContext();
    gen.setCurrentValue(value); // must set manually, or else the result of context.getCurrentValue() will be null。this method will call context.setCurrentValue(value);

    gen.writeStartObject(); // writeStartObject(value) will call setCurrentValue(value) well
    Class<?> entityClass = value.getClass();
    Method[] methods = entityClass.getMethods(); // include method inherited from super classes
    for(Method method : methods) {
        // check whether serialization will be recursive
        if (willRecursive(gen, context, method)) {
            gen.writeEndObject();
            return;
        }

        // method annotated with @Field
        Field fieldAnnotation = method.getAnnotation(Field.class);
        if(fieldAnnotation != null) {
            serializeField(value, gen, entityClass, method, fieldAnnotation);
        }else {
            MultiFields multiFields = method.getAnnotation(MultiFields.class);
            if(multiFields != null) {
                Field mainFieldAnnotation = multiFields.mainField();
                serializeField(value, gen, entityClass, method, mainFieldAnnotation);
            }
        }
    }

    // gen.writeObjectField("extra_field", "whatever_value");
    gen.writeEndObject();

}
 

@Override
protected void serializeContents(Collection<?> value, JsonGenerator jsonGenerator,
		SerializerProvider serializerProvider) throws IOException {

	jsonGenerator.setCurrentValue(value);

	PropertySerializerMap serializers = this._dynamicSerializers;
	TypeSerializer typeSerializer = this._valueTypeSerializer;

	int index = -1;

	try {
		for (Object element : CollectionUtils.nullSafeCollection(value)) {

			index++;

			if (Objects.isNull(element)) {
				serializerProvider.defaultSerializeNull(jsonGenerator);
			}
			else {

				Class<?> elementType = element.getClass();

				JsonSerializer<Object> serializer = resolveSerializer(serializerProvider, elementType);

				if (typeSerializer != null) {
					serializer.serializeWithType(element, jsonGenerator, serializerProvider, typeSerializer);
				}
				else {
					serializer.serialize(element, jsonGenerator, serializerProvider);
				}
			}
		}
	}
	catch(Exception cause) {
		wrapAndThrow(serializerProvider, cause, value, index);
	}
}
 

@Override
public void serializeWithType(
        T value, JsonGenerator gen,
        SerializerProvider ctxt, TypeSerializer typeSer
) throws IOException {
    gen.setCurrentValue(value);
    WritableTypeId typeIdDef = typeSer.writeTypePrefix(gen, ctxt,
            typeSer.typeId(value, JsonToken.START_OBJECT));
    if (!isEmpty(ctxt, value)) {
        serializeFields(value, gen, ctxt);
    }
    typeSer.writeTypeSuffix(gen, ctxt, typeIdDef);
}
 

@Override
public void serializeWithType(C value, JsonGenerator g, SerializerProvider ctxt, TypeSerializer typeSer)
        throws IOException {
    g.setCurrentValue(value);
    WritableTypeId typeIdDef = typeSer.writeTypePrefix(g, ctxt, typeSer.typeId(value, JsonToken.START_ARRAY));
    serializeContents(value, g);
    typeSer.writeTypeSuffix(g, ctxt, typeIdDef);
}