Converting map to POJO with Jackson ObjectMapper throws exception

Question

I have a MultivaluedMap<String, String> which represents the form parameters of a POST request. I'd like to convert a POJO from this class with only those fields I need for further processing. I found some answers which suggest using convertValue() from the Jackson ObjectMapper.

Convert a Map<String, String> to a POJO

public void process(MultivaluedMap<String, String> formParams) {
  ObjectMapper objectMapper = new ObjectMapper();
  final MyPojo myPojo = objectMapper.convertValue(formParams,MyPojo.class);
}

POJO

@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@JsonIgnoreProperties(ignoreUnknown = true)
public class MyPojo {

    private String status;

    @JsonProperty("order_no")
    private String orderId;

    @JsonProperty("tid")
    private String transactionId;
}

However this fails with the following exception:

com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.lang.String` out of START_ARRAY token
 at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: MyPojo["order_no"])

This is how the input looks like in the debugger:

Answer 1

I need to replace the String type with ArrayList<String> which seems to work:

@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@JsonIgnoreProperties(ignoreUnknown = true)

public class MyPojo {

    private ArrayList<String> status;

    @JsonProperty("order_no")
    private ArrayList<String> orderId;

    @JsonProperty("tid")
    private ArrayList<String> transactionId;
}