Deserializing JSON using Jackson 2

Question

I have a json

[
  {
    "host": {
      "name": "anotherfullhost",
      "id": 55602819,
      "operatingsystem_id": 1073012828,
      "hostgroup_id": null
    }
  },
  {
    "host": {
      "name": "dhcp.mydomain.net",
      "id": 219245707,
      "operatingsystem_id": 1073012828,
      "hostgroup_id": null
    }
  },
  {
    "host": {
      "name": "my5name.mydomain.net",
      "id": 980190962,
      "operatingsystem_id": 1073012828,
      "hostgroup_id": null
    }
  }
]

I would like to construct a Collection by deserializing the above json. What jackson annotations should I add to the below Host class


public class Host {
    @JsonProperty("id")
    private Long id;

    @JsonProperty("name")
    private String name;

    @JsonProperty("operatingsystem_id")
    private Long operatingSystemId;

    @JsonProperty("hostgroup_id")
    private Long hostGroupId;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Long getOperatingSystemId() {
        return operatingSystemId;
    }

    public void setOperatingSystemId(Long operatingSystemId) {
        this.operatingSystemId = operatingSystemId;
    }

    public Long getHostGroupId() {
        return hostGroupId;
    }

    public void setHostGroupId(Long hostGroupId) {
        this.hostGroupId = hostGroupId;
    }

    @Override
    public String toString() {
        return "Host{" +
                "name='" + name + '\'' +
                '}';
    }
}

Any suggestions?

Note - I am using jackson 2.x API.

Thanks.

Update Adding a wrapper object does the trick.


public class HostWrapper {
    @JsonProperty("host")
    private Host host;

    public Host getHost() {
        return host;
    }

    public void setHost(Host host) {
        this.host = host;
    }

    @Override
    public String toString() {
        return host.toString();
    }
}

and the below code to deserialize

        ObjectMapper mapper = new ObjectMapper();
        HostWrapper[] host = mapper.readValue(jsonString, HostWrapper[].class);

I do "Host[] host = mapper.readValue(jsonString, Host[].class);" and I get an exception - Caused by: com.fasterxml.jackson.databind.JsonMappingException: Current token not START_OBJECT (needed to unwrap root name 'Host[]'), but START_ARRAY — Andy Dufresne, Aug 28 '13 at 06:38
I even tried creating a wrapper object called HostWrapper which has a property Host but that too gives the same exception. — Andy Dufresne, Aug 28 '13 at 06:40

score 3 · Accepted Answer · edited May 23 '17 at 12:14

3

Please see this post - This should be the same issue than yours, even if a different API is used:

JsonMappingException: Current token not START_OBJECT (needed to unwrap root name 'Transaction[]'), but START_ARRAY

edited May 23 '17 at 12:14

Community

1
1

answered Aug 28 '13 at 07:40

Christopher Stock

1,399
15
18

1

Great this works. I had made a mistake of setting the UNWRAP_ROOT_VALUE to true. – Andy Dufresne Aug 28 '13 at 08:33

Deserializing JSON using Jackson 2

1 Answers1