want to deserialize json string into java object with arraylist

Question

java object: MyObject has a list of AnotherObject1 and AnotherObject1 also have a list of AnotherObject2

class MyObject{

private String                  status;

private String                  message;

private List<AnotherObject1>            data;
public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public List<AnotherObject1> getData() {
        return data;
    }

    public void setData(List<AnotherObject1> data) {
        this.data = data;
        }
}

Class AnotherObject1{
private Integer                 group_id;

 private List<AnotherObject2>           anotherList;
public Integer getGroup_id() {
   return group_id;
}

public void setGroup_id(Integer group_id) {
   this.group_id = group_id;
}

public List<AnotherObject2> getAnotherList() {
  return smsList;
}

public void setAnotherList(List<AnotherObject2> anotherList) {
   this.anotherList = anotherList;
}

}

class AnotherObject2{
  private String                    customid;

    private String                  customid1   ;

    private Long                    mobile;

    private String                  status;

    private String                  country;

    public String getCustomid() {
        return customid;
    }

    public void setCustomid(String customid) {
        this.customid = customid;
    }

    public String getCustomid1() {
        return customid1;
    }

    public void setCustomid1(String customid1) {
        this.customid1 = customid1;
    }

    public Long getMobile() {
        return mobile;
    }

    public void setMobile(Long mobile) {
        this.mobile = mobile;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }


}

JSON String: this is my json string by which i want to make an java object using object mapper

String response="{\"status\":\"OK\",\"data\":{\"group_id\":39545922,\"0\":{\"id\":\"39545922-1\",\"customid\":\"\",\"customid1\":\"\",\"customid2\":\"\",\"mobile\":\"910123456789\",\"status\":\"XYZ\",\"country\":\"IN\"}},\"message\":\"WE R Happy.\"}"

ObjectMapper code //convert string to response object

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
objectMapper.readValue(responseBody, MyObject.class);

exception: here is the exception

com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of START_OBJECT token
 at [Source: {"status":"OK","data":{"group_id":39545922,"0":{"id":"39545922-1","customid":"","customid1":"","customid2":"","mobile":"910123456789","status":"GOOD","country":"IN"}},"message":"We R happy."}; line: 1, column: 15] (through reference chain: MyObject["data"])
    at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:148)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:854)
    at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:850)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.handleNonArray(CollectionDeserializer.java:292)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:227)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:217)
    at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:25)
    at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:520)
    at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:95)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:256)
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:125)
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3702)
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2714)
    at abc.disp(RestClientImpl.java:210)
    at abc.disp(RestClientImpl.java:105)
    at Application.<init>(Application.java:42)
    at Application.main(Application.java:45)

please guide me how to make it possible.

Answer 1

Problem is quite simple: you claim data should become Java List; and this requires that JSON input for it should be JSON Array. But what JSON instead has is a JSON Object.

So you either need to change POJO definition to expect something compatible with JSON Object (a POJO or java.util.Map); or JSON to contain an array for data.

Answer 2

First as Naveen Ramawat said your code is not compilable as it is.

• In the class AnotherObject1 getSmsList should take AnotherObject2 and setSmsList should take AnotherObject2 also as parameter.
• In the class MyObject setData and getData should use AnotherObject1 as parameters

Second your JSON string is not valid it should be sommething like that:

{"status":"OK","data":[{"group_id":39545922,"smsList":[{"customid":"39545922-1","customid1":"","mobile":913456789,"status":"XYZ","country":"XYZ"}]}]}

Here is the code that I used :

MyObject.java:

    import java.util.List;

    class MyObject {

        private String status;

        private String message;

        private List<AnotherObject1> data;

        public String getStatus() {
            return status;
        }

        public void setStatus(String status) {
            this.status = status;
        }

        public String getMessage() {
            return message;
        }

        public void setMessage(String message) {
            this.message = message;
        }

        public List<AnotherObject1> getData() {
            return data;
        }

        public void setData(List<AnotherObject1> data) {
            this.data = data;
        }
    }

AnotherObject1.java :

    import java.util.List;

    public class AnotherObject1 {
        private Integer group_id;

        private List<AnotherObject2> smsList;

        public Integer getGroup_id() {
            return group_id;
        }

        public void setGroup_id(Integer group_id) {
            this.group_id = group_id;
        }

        public List<AnotherObject2> getSmsList() {
            return smsList;
        }

        public void setSmsList(List<AnotherObject2> smsList) {
            this.smsList = smsList;
        }
    }

AnotherObject2.java :

    public class AnotherObject2 {

        private String customid;

        private String customid1;

        private Long mobile;

        private String status;

        private String country;

        public String getCustomid() {
            return customid;
        }

        public void setCustomid(String customid) {
            this.customid = customid;
        }

        public String getCustomid1() {
            return customid1;
        }

        public void setCustomid1(String customid1) {
            this.customid1 = customid1;
        }

        public Long getMobile() {
            return mobile;
        }

        public void setMobile(Long mobile) {
            this.mobile = mobile;
        }

        public String getStatus() {
            return status;
        }

        public void setStatus(String status) {
            this.status = status;
        }

        public String getCountry() {
            return country;
        }

        public void setCountry(String country) {
            this.country = country;
        }

    }

To get the JSON string :

    import org.json.JSONObject;
    import org.json.XML;

    import com.google.gson.Gson;

    MyObject myObj = new MyObject();
    ArrayList<AnotherObject2> smsList = new ArrayList<AnotherObject2>();
    ArrayList<AnotherObject1> data = new ArrayList<AnotherObject1>();
    AnotherObject1 ao1 = new AnotherObject1();
    ao1.setGroup_id(39545922);
    ao1.setSmsList(smsList);
    AnotherObject2 sms = new AnotherObject2();
    sms.setCountry("XYZ");
    sms.setCustomid("39545922-1");
    sms.setCustomid1("");
    sms.setMobile((long) 913456789);
    sms.setStatus("XYZ");
    smsList.add(sms);
    ao1.setSmsList(smsList);
    data.add(ao1);
    myObj.setStatus("OK");
    myObj.setData(data);
    // Build a JSON string to display
    Gson gson = new Gson();
    String jsonString = gson.toJson(myObj);
    System.out.println(jsonString);
    // Get an object from a JSON string
    MyObject myObject2 = gson.fromJson(jsonString, MyObject.class);
    // Display the new object
    System.out.println(gson.toJson(myObject2));

Answer 3

Your code itself is not compailable ...

private List<AnotherObject1> data; // Your class member is list of AnotherObject1

and below it is used as List of SMSDTO in getter and setter

public List<SMSDTO> getData() {
    return data;
}