Map JSON to pojo using Jackson for List that have different parameters

问题

JSON FORMAT:

[
{
    "0":
    {
        "cast":"",
        "showname":"woh pagle",
        "type":"Episodes"
    },
    "video":[
        {
            "src":"video.mp4"
        },
        {
            "DRM":"False"
        }
    ]
}
]

Here problem is I am getting below exception:

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token at [Source: java.io.StringReader@1c9ca1; line: 1, column: 55617] (through reference chain: com.apalya.myplex.valueobject.ThirdPartyContentDetailsArray["video"])

My pojo classes are :

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonProperty("0")
private ThirdPartySubContentDetails subContent;

@JsonProperty("video")
private List<ThirdPartySubContentVideoInfo> video;

My Sub class pojo is :

private String src;

@JsonIgnore
@JsonProperty("DRM")
private String drm;

Please help me to write a pojo for that video list.

回答1:

Your json starts as an array and not as an Object. The important part to change is how the Objectmapper should generate your json. For returning a List you need to do it this way:

List<FirstJson> jsonList = mapper.readValue(json, new TypeReference<List<FirstJson>>(){});

Here is my short working test I implement locally:

public static void main(String[] args) {
    String json = "[{\"0\":{\"cast\":\"\",\"showname\":\"wohpagle\",\"type\":\"Episodes\"},\"video\":[{\"src\":\"video.mp4\"},{\"DRM\":\"False\"}]}]";
    ObjectMapper mapper = new ObjectMapper();

    List<FirstJson> jsonList = mapper.readValue(json, new TypeReference<List<FirstJson>>(){});
    System.out.println(jsonList.toString());
}

The first part of your JsonArray in Pojo.(Named it FirstJson)

public class FirstJson{

        @JsonProperty("0")
        private FirstJson subContent;

        private String cast;
        private String showname;
        private String type;

        @JsonProperty("video")
        private List<Video> videos;

      //getter/setter

And the Video Pojo:

public class Video {

        private String src;

        @JsonProperty("DRM")
        private String drm;

      //getter/setter

Just a sidenote: If you declare your pojos in the same class file, the classes should be static. public static class FirstJson

回答2:

According to the JSON structure described in the question, the following should be the POJOs:

public class MainPojo
{
     @JsonProperty("0")
     private ThirdPartySubContentDetails subContent;

     @JsonProperty("video")
     private List<ThirdPartySubContentVideoInfo> video;

     // Getters and Setters for subContent and video
}

class ThirdPartySubContentDetails
{
    private String cast;
    private String showName;
    private String type;

    // Getters and Setters for cast, showName and type
}

@JsonIgnoreProperties(ignoreUnknown = true)
class ThirdPartySubContentVideoInfo
{
    @JsonProperty("src")
    private String src;

    @JsonProperty("DRM")
    private String drm;

    // Getters and Setters for src and drm
}

You should call the deserializer method as follows:

 List<MainPojo> list = new ObjectMapper().readValue(json, new TypeReference<List<MainPojo>>(){});

来源：https://stackoverflow.com/questions/36786514/map-json-to-pojo-using-jackson-for-list-that-have-different-parameters

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