[Bug] 泛型字段 deserializeUsing 失效

[timandy]

fastjson/src/main/java/com/alibaba/fastjson/parser/deserializer/DefaultFieldDeserializer.java

Lines 53 to 69 in 9b8b186

	public void parseField(DefaultJSONParser parser, Object object, Type objectType, Map<String, Object> fieldValues) {
	if (this.fieldValueDeserilizer == null) {
	getFieldValueDeserilizer(parser.getConfig());
	}
	ObjectDeserializer fieldValueDeserilizer = this.fieldValueDeserilizer;
	Type fieldType = fieldInfo.fieldType;
	if (objectType instanceof ParameterizedType) {
	ParseContext objContext = parser.getContext();
	if (objContext != null) {
	objContext.type = objectType;
	}
	if (fieldType != objectType) {
	fieldType = FieldInfo.getFieldType(this.clazz, objectType, fieldType);
	fieldValueDeserilizer = parser.getConfig().getDeserializer(fieldType);
	}
	}

58 行可能通过 deserializeUsing 注解获取过字段上的 Codec , 在 67 行不应该暴力覆盖. 需要判断下当前是否有值,如果为 null 在覆盖.

用例 同
#3008

public class OfficeBean<T> {
    @JSONField(name = "Preference", deserializeUsing = PreferenceDeserializer.class)
    private T preferenceBean;
}

[darren-wang]

该问题 的修复带来了新的bug：#3810