Unable to parse date value using Jackson and Gson-CodePudding

I have a Java Spring REST API that receives a JSON string in the body of a POST request. JSON string is large; it contains multiple nested objects.

Upon receiving the POST request, I am converting the string into a DTO object.

Problem

One of the nested object contains a key startDate that is not being de-serialized correctly.

Value of the startDate object is:

"startDate": 1622746800000

I have tried de-serializing the string using Jackson as well as Gson BUT both of them fail to parse the startDate correctly.

Exception thrown when using Gson:

java.text.ParseException: Unparseable date: "1622746800000"

If I pass the startDate as null, everything works fine - string is converted into DTO object correctly.

Question

Any idea what could be a possible cause for this problem? How can I fix it?

P.S. Value for startDate is received as part of a response from the backend. I am sending that same response string to the backend in the POST request body.

Code:

Following is the code that parses the string received in the request's body:

ObjectMapper mapper = new ObjectMapper();
MyDTOClass evData = mapper.convertValue(evDataJsonStr, MyDTOClass.class);

I have tried with Gson as well:

Gson mapper = new Gson();
MyDTOClass evData = mapper.fromJson(evDataJsonStr, MyDTOClass.class);

This

Above value when serialized becomes: 1622746800000 and this is what i am trying to de-serialize.

CodePudding user response：

In my understanding Gson cannot de-serialize epoch time by default. But Jackson can.

For Jackson you can do the following,

ObjectMapper mapper = new ObjectMapper();
MyDTOClass evData = mapper.readValue(evDataJsonStr, MyDTOClass.class);

Please note that its ObjectMapper's readValue method not convertValue method