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I have this serialized JSON given to me as string

"{\"UniqueId\":[\"69570d12-598d-4aca-abe9-4d0e7b286fe5\",\"949cd142-3eca-4fd8-b8ea-b681f65c69ca\"],\"CustomerOffers\":{\"137966\":[05],\"137986\":[11],\"137987\":[38]},\"Success\":true,\"ErrorMessages\":[\"No Error\"],\"ErrorType\":\"null\"}"

I need to deserialize it to Java object.

I created this object class 

public class Data {

    public List<UUID> UniqueId;
    public Map<Integer, List<Integer>> CustomerOffers;
    public Boolean Success;
    public List<String> ErrorMessages;
    public String ErrorType;    

   // Usual Getters and Setters here
}

Then I created the method to grab the String and deserialize it, using com.fasterxml.jackson.databind.ObjectMapper 

public class Deserializing {

public void processing(String input){

        ObjectMapper mapper = new ObjectMapper();
        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        mapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);

        try {

            // JSON string to Java object
            Data data = mapper.readValue(input, Data.class); //This returns exception
            System.out.println(data);

        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    
}

Then the main class to call the method. 

public class Testing {

    @Test
    private void testing() throws ClassNotFoundException {
    Deserializing deserializing = new Deserializing();
    String rawData =  "\"{\\\"UniqueId\\\":[\\\"69570d12-598d-4aca-abe9-4d0e7b286fe5\\\",\\\"949cd142-3eca-4fd8-b8ea-b681f65c69ca\\\"],\\\"CustomerOffers\\\":{\\\"137966\\\":[05],\\\"137986\\\":[11],\\\"137987\\\":[38]},\\\"Success\\\":true,\\\"ErrorMessages\\\":[\\\"No Error\\\"],\\\"ErrorType\\\":\\\"null\\\"}\"";
    deserializing.processing(rawData);
    }

}

After I run it (using TestNG), I get this error message

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance ofData(although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value

I am wondering, where could I do wrongly?

Thank You

PS: the original serialized JSON data that I get from the txt file looks like this "{\"UniqueId\":[\"69570d12-598d-4aca-abe9-4d0e7b286fe5\",\"949cd142-3eca-4fd8-b8ea-b681f65c69ca\"],\"CustomerOffers\":{\"137966\":[48],\"137986\":[48],\"137987\":[48]},\"Success\":true,\"ErrorMessages\":[\"No Error\"],\"ErrorType\":\"null\"}"
When I copy paste it to IntelliJ editor, escape string will need to be added (IntelliJ adds it automatically). If I grab the data straight from the txt file and use it, I just pass it to the method public void processing(String input) without worrying the escape characters. Not sure if this is correct though ...

keylogger
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    you have `\\\"` in your string which make it looks like \" in json so it might be cause for exception replace all of them with single `\"` – Mustahsan Sep 24 '19 at 05:47
  • Thanks for the comment. I added a note in the original posting. Thanks. – keylogger Sep 24 '19 at 05:54
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    If you are worried about IntelliJ auto inserting these, then dont paste your content inside `""` just directly paste the data you copied as it is already a string so you dont need to type qoutes yourself – Mustahsan Sep 24 '19 at 05:54
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    Also Jackson will not be able to parse numbers with leading zeros like `05`. See [this](https://stackoverflow.com/questions/27361565/why-is-json-invalid-if-an-integer-begins-with-a-leading-zero) – Michał Krzywański Sep 24 '19 at 05:55
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    for unescaping this `String` you could use `rawData = rawData.replace("\"", "").replace("\\", "\"");` – Michał Krzywański Sep 24 '19 at 06:00
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    Apparently the issue is caused by the raw data that was already escaped. The solution from @michalk works like charm. It needs to be un-escaped. May I ask what is the idea under the hood? As far as I know, those special characters always need to be escaped in Java before further processing. Why in this case, it is the other way around ? Is it Jackson's requirement? Thanks. – keylogger Sep 24 '19 at 09:30

0 Answers0