write regex in JsonFormat pattern - json

Question

#JsonFormat(shape = JsonFormat.Shape.STRING, pattern ="yyyy-MM-dd'T'HH:mm:ss.SSS")
is it possible to write regex in pattern? I could not
pattern ="yyyy-MM-dd'T'HH:mm:ss.SSS(Z?)"
I want to make Z as optional
any links suggestions?

Answer 1

I ended up creating custom deserializer based on LocalDateDeserializer.INSTANCE and moved the regex there.
After registering the deserializer the object mapper as a custom module the #JsonFormat annotation is no longer required:
#Bean
public ObjectMapper createObjectMapper() {
return new ObjectMapper()
.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
.registerModule(new JavaTimeModule())
.registerModule(new CustomTimeModule());
}
and defined the deserializer in the CustomTimeModule
class CustomTimeModule extends SimpleModule {
public CustomTimeModule() {
super();
addDeserializer(LocalDate.class, CustomLocalDateDeserializer.INSTANCE);
}
}
and finally the regex part, in my case was cutting of the optional non-standard time zone that i was sometimes getting after the date, but could be easily extended to match your case:
public class CustomLocalDateDeserializer extends JSR310DateTimeDeserializerBase<LocalDate> {
private static final long serialVersionUID = 1L;
private static final DateTimeFormatter DEFAULT_FORMATTER = DateTimeFormatter.ISO_LOCAL_DATE;
public static final CustomLocalDateDeserializer INSTANCE = new CustomLocalDateDeserializer();
private CustomLocalDateDeserializer() {
this(DEFAULT_FORMATTER);
}
public CustomLocalDateDeserializer(DateTimeFormatter dtf) {
super(LocalDate.class, dtf);
}
#Override
protected JsonDeserializer<LocalDate> withDateFormat(DateTimeFormatter dtf) {
return new CustomLocalDateDeserializer(dtf);
}
#Override
public LocalDate deserialize(JsonParser parser, DeserializationContext context) throws IOException
{
if (parser.hasToken(JsonToken.VALUE_STRING)) {
String string = parser.getText().trim();
if (string.length() == 0) {
return null;
}
// >>>>>>> regex part comes here <<<<<<<
string = parser.getText().trim().substring(0, 10);
// >>>>>>> regex part comes here <<<<<<<
// as per [datatype-jsr310#37], only check for optional (and, incorrect...) time marker 'T'
// if we are using default formatter
try {
return LocalDate.parse(string, _formatter);
} catch (DateTimeException e) {
return _handleDateTimeException(context, e, string);
}
}
if (parser.isExpectedStartArrayToken()) {
JsonToken t = parser.nextToken();
if (t == JsonToken.END_ARRAY) {
return null;
}
if (context.isEnabled(DeserializationFeature.UNWRAP_SINGLE_VALUE_ARRAYS)
&& (t == JsonToken.VALUE_STRING || t==JsonToken.VALUE_EMBEDDED_OBJECT)) {
final LocalDate parsed = deserialize(parser, context);
if (parser.nextToken() != JsonToken.END_ARRAY) {
handleMissingEndArrayForSingle(parser, context);
}
return parsed;
}
if (t == JsonToken.VALUE_NUMBER_INT) {
int year = parser.getIntValue();
int month = parser.nextIntValue(-1);
int day = parser.nextIntValue(-1);
if (parser.nextToken() != JsonToken.END_ARRAY) {
throw context.wrongTokenException(parser, handledType(), JsonToken.END_ARRAY,
"Expected array to end");
}
return LocalDate.of(year, month, day);
}
context.reportInputMismatch(handledType(),
"Unexpected token (%s) within Array, expected VALUE_NUMBER_INT",
t);
}
if (parser.hasToken(JsonToken.VALUE_EMBEDDED_OBJECT)) {
return (LocalDate) parser.getEmbeddedObject();
}
// 06-Jan-2018, tatu: Is this actually safe? Do users expect such coercion?
if (parser.hasToken(JsonToken.VALUE_NUMBER_INT)) {
return LocalDate.ofEpochDay(parser.getLongValue());
}
return _handleUnexpectedToken(context, parser, "Expected array or string.");
}