How to parse properly Date string to java.util.Date when deserializing JSON to Java POJO with Jackso-CodePudding

I am implementing an application that gets the data from certin endponts in json formats and tries to deserialize tem to Java Objects but I have problems with the parsing of the date in the JSON.This is how the Date looks like in the JSON: "/Date(1633122000000 0300)/" and I cannot find information in Google how to successfully parse this format.

{
  "Date": "/Date(1633122000000 0300)/",
  "Filled": 0,
  "Needed": 0,
  "Paid": 0
}

This is the pojo I use to deserialize the data to using Jackson ObjectMapper:

import java.util.Date;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class TimeByDateSheet {

    @JsonProperty("Date")
    @JsonFormat(timezone = "GMT 03:00")
    @JsonDeserialize(using = DateDeserializer.class, as=Date.class)
    private Date date;
    
    @JsonProperty("Filled")
    private Long filled;
 
    @JsonProperty("Needed")
    private Long needed;
    
   @JsonProperty("Paid")
   private Integer paid;

}

And here is my DateDeserializer:

@SuppressWarnings("serial")
public class DateDeserializer extends JsonDeserializer<Date> {

@Override
public Date deserialize(JsonParser jsonParser, DeserializationContext context) 
throws IOException, JsonProcessingException {
    SimpleDateFormat simpleDateFormat = 
         new SimpleDateFormat("yyyy-MM-dd HH:mm:ss zzz", Locale.getDefault());
    String dateStr = jsonParser.getText();
    Date date;
    try{
        date = simpleDateFormat.parse(dateStr);
    }catch(ParseException e){
        throw new RuntimeException(e);
    }
    return date;
}

}

But it does not work correctly. I get the following exception:

Connected to the target VM, address: '127.0.0.1:52760', transport: 'socket' SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". SLF4J: Defaulting to no-operation (NOP) logger implementation SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details. Exception in thread "main" com.fasterxml.jackson.databind.JsonMappingException: java.text.ParseException: Unparseable date: "/Date(1633035600000 0300)/" (through reference chain: java.util.ArrayList[0]->com.dataart.forecasts.pojo.timebydate.TimeByDateSheet["Date"]) at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:392) at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:351) at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.wrapAndThrow(BeanDeserializerBase.java:1821) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:315) at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:176) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer._deserializeFromArray(CollectionDeserializer.java:355) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:244) at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:28) at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:322) at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4675) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3630) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3613) at com.dataart.forecasts.DataProcessor.deserializeTimeByDateSheetsList(DataProcessor.java:198) at com.dataart.forecasts.ForecastReportApplication.main(ForecastReportApplication.java:50) Caused by: java.lang.RuntimeException: java.text.ParseException: Unparseable date: "/Date(1633035600000 0300)/" at com.dataart.forecasts.DateDeserializer.deserialize(DateDeserializer.java:28) at com.dataart.forecasts.DateDeserializer.deserialize(DateDeserializer.java:16) at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129) at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:313) ... 10 more Caused by: java.text.ParseException: Unparseable date: "/Date(1633035600000 0300)/" at java.base/java.text.DateFormat.parse(DateFormat.java:395) at com.dataart.forecasts.DateDeserializer.deserialize(DateDeserializer.java:26) ... 13 more

Could someone help me, please. I searched a lot in internet but could not find a solution. Thank you in advance! :)

CodePudding user response：

It looks like there is a problem generating the JSON. I really don't think you want to have the dates formatted like that. Right now, you have some odd text surrounding a unix timestamp in milliseconds followed by a zone offset. You are also using the old and rather frowned-upon Date and SimpleDateFormat classes rather than the newer java.time API. However, it is possible to deserialize your date format. Here is one way:

public class DateDeserializer extends JsonDeserializer<Date> {
    @Override
    public Date deserialize(JsonParser jsonParser, DeserializationContext context) 
            throws IOException, JsonProcessingException {
        Pattern pattern = Pattern.compile("/Date\\((\\d )([ -]\\d )\\)/");
        Matcher matcher = pattern.matcher(jsonParser.getText());
        if (matcher.find()) {
            String timestamp = matcher.group(1);
            String offset = matcher.group(2);
            Instant instant = Instant.ofEpochMilli(Long.parseLong(timestamp));
            ZonedDateTime zdt = instant.atZone(ZoneId.of(offset));
            instant = zdt.toInstant();
            return Date.from(instant);
        } else {
          throw new RuntimeException("Invalid format: "   jsonParser.getText());
        }
    }
}

CodePudding user response：

@DavidConrad Thank you, I will try your solution. By the way, for now I made a workaround that works for me for now:

@Override
    public Date deserialize(JsonParser jsonParser, DeserializationContext context) throws IOException, JsonProcessingException {
        SimpleDateFormat dateFormattter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dateStr = jsonParser.getText();
        String timeZone = dateStr.substring(dateStr.indexOf(" ")   1, dateStr.indexOf(")"));
        String timeZoneShift = String.format("%s:%s",
                timeZone.substring(0, timeZone.length()/2),
                timeZone.substring(timeZone.length()/2));
        dateFormattter.setTimeZone(TimeZone.getTimeZone(String.format("GMT %s", timeZoneShift)));
        Long millis = 0L;
        if (dateStr.contains(" ") && !dateStr.contains("-")) {
            millis = Long.parseLong(dateStr.substring(dateStr.indexOf("(")   1, dateStr.indexOf(" ")));
        } else if (dateStr.contains(" ") && !dateStr.contains("-")) {
            millis = Long.parseLong(dateStr.substring(dateStr.indexOf("(")   1, dateStr.indexOf(")")));
        }
        Date date = new Date(millis);
        String stringDate= dateFormattter.format(date);
        try {
            date = dateFormattter.parse(stringDate);
        } catch (ParseException e) {
            throw new RuntimeException(e);
        }
        return date;
    }