How to read a json file with array, how can i modify my code to read json which has result and HD

Question

I'm writing to write a small miroservice to read a json file and put it into postgredb. Currently it is working fine. But now i want to modify my json file with array. previously 'result' and 'HD' were not there.

{
"result": {
  "HD": [
  {
    "LOGADDR": "1000002624",
    "CATEGORY": "ADD",
    "NAME": "POLYTEC COMPOSITES GERMANY",
    "STATUS": "ACTI"
   }
  ]
 }
}

my below code is working is fine without result and HD

CommandLineRunner runner(ResponseService responseService) {
    return args -> {
        // read JSON and load json
        ObjectMapper mapper = new ObjectMapper();
        TypeReference<List<Response>> typeReference1 = new TypeReference<List<Response>>() {};
        InputStream inputStream1 = TypeReference.class.getResourceAsStream("/json/response.json");
        try {
            List<Response> responses = mapper.readValue(inputStream1, typeReference1);
            responseService.save(responses);
            System.out.println(responses);
            System.out.println("response saved");
        } catch (IOException e) {
            System.out.println("not saved" + e.getMessage());
        }

    };
}

my domain file

@AllArgsConstructor
@Data
@Entity
@Table(name = "receive")
@JsonIgnoreProperties(ignoreUnknown = true)
public class Response {
@Id
@JsonProperty("LOGADDR")
private String LOGADDR;

@JsonProperty("CATEGORY")
@Column(name = "CATEGORY")
private String CATEGORY;

@JsonProperty("NAME")
@Column(name = "NAME")
private String NAME;

@JsonProperty("STATUS")
@Column(name = "STATUS")
private String STATUS;

public Response() {

}
}

gantoin · Accepted Answer · 2021-03-22 11:36:55Z

1

You can update your domain object tree like your JSON :

    @Getter
    class Foo {
        Result result;
    }

    @Getter
    class Result {
        List<Response> hd;
    }

    @Getter
    class Response {
       ...
    }

    ObjectMapper mapper = new ObjectMapper();
    TypeReference<Foo> typeReference1=new TypeReference<Foo>(){};

    InputStream inputStream1 = TypeReference.class.getResourceAsStream("/json/response.json");try
    {
        Foo foo = mapper.readValue(inputStream1, typeReference1);
        List<Response> responses = foo.getResult().getHd();
        responseService.save(responses);
        System.out.println(responses);
        System.out.println("response saved");
   ...

answered Mar 22, 2021 at 11:36

gantoin

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4 Comments

coldfusion_xxxx Over a year ago

Thank you so much! it says Entities must not be null now

coldfusion_xxxx Over a year ago

in Result class getHD() is returning null. Am doing something wrong ?

gantoin Over a year ago

` @Getter class Result {; @JsonProperty("HD") List<Response> hd = new ArrayList<>(); } `

coldfusion_xxxx Over a year ago

Thank you very much! this is exactly what i was looking for! Just out of curiosity i just wanted to know what happens if i keep receiving more arrays more HD1, HD2.....HDN how to read those if in case i dont know how many arrays they are sending inside result

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