JSON Deserialization error in Java

Question

I am trying to deserialize some JSON which I got from the eBay API but I am getting the error: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.String out of START_ARRAY token

The JSON that is returned has many levels to it. e.g.

{"searchResult":[{"@count":"100","item":[{"itemId":["281492499859"],"title":["Panasonic Lumix TZ20 Digital Camera in Good Condition"],... etc

This is for a property called itemId in CompletedListing (class defined below)

I am calling this method with the line:

CompletedListingContainer listing = mapper.readValue(new File("C:\\resource\\jsonresult.txt"), CompletedListingContainer.class);`

Here are my classes.

CompletedListingContainer

public class CompletedListingContainer {

  private ArrayList<CompletedListing> item;

  private ArrayList<SearchResult> searchResult;

  private List<String> paginationOutput;

  @JsonIgnore
  public List<String> getPaginationOutput() {
      return paginationOutput;
  }

  public ArrayList<SearchResult> getSearchResult() {
      return searchResult;
  }

  public ArrayList<CompletedListing> getItem() {
      return item;
  } 
}

SearchResult

public class SearchResult {

  @JsonProperty("@count")
  private String count;

  private ArrayList<CompletedListing> item;

  @JsonIgnore
  public String getCount() {
      return count;
  }

  public ArrayList<CompletedListing> getItem() {
      return item;
  }
}

CompletedListing

public class CompletedListing {

  @JsonProperty("itemId")
  private String itemId;

  private String title;

  @JsonProperty("itemId")
  public String getItemId() {
    return itemId;
  }

  @JsonProperty("title")
  public String getTitle() {
    return title;
  }
}

Any help would be greatly appreciated. Let me know if you need any more information.

Vlad · Accepted Answer · 2014-11-18 13:32:29Z

1

{"itemId":["281492499859"] means your CompletedListing.itemId property should be a list or array.

answered Nov 18, 2014 at 13:32

Vlad

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3 Comments

James Fox Over a year ago

Thanks, this was the problem. I didn't realise it needed to be a List.

Vlad Over a year ago

@JamesFox glad to help, please note that same goes for title

James Fox Over a year ago

Yes, I am changing for all the properties as I have more that I didn't add to the question.

devops · Accepted Answer · 2014-11-18 13:31:49Z

0

put private ArrayList<CompletedListing> item in your SearchResult class and remove it from CompletedListingContainer

look at your json file structure:

{
   "searchResult":[
       {
        "count":"100",
        "item":[
               {"itemId":["281492499859"]...
       },
   ....
}

try this online tool to generate Java classes from json

answered Nov 18, 2014 at 13:31

devops

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1 Comment

James Fox Over a year ago

This hasn't fixed the issue but I can see that it was wrong to have that in the CompletedListingContainer class.

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