Return object as Json in java

Question

We would like to return Object class as JSON string

 public static String genJson(Response r, Auth auth) {
            Auth p = new Auth();
            ObjectMapper mapper = new ObjectMapper();

            String transactionResult = r.getTransactionResult();
            if (transactionResult.equalsIgnoreCase("APPROVED")) {
                p.setPay_resp_resp_code("00");
                p.setPay_resp_desc("Waiting");

                try {
                    jsonStr = mapper.writeValueAsString(p);
                } catch (JsonProcessingException e) {
                    e.printStackTrace();
                }
            }
            return jsonStr;
        }

In Auth class, I have five variables, but I only want it to display two, which are resp_code and resp_desc. But the above code always return 5 variables.

Edit

This is how our code suppose to work. First it will convert jsonString to object class named Auth. Then it will execute the if statement.

 @RequestMapping("/authstep")
    @ResponseBody
    private String AuthRequest(@RequestBody String jsonString) {

        log.info("========== Receive JSON object request ==========");

        if (jsonString != null) {

            Auth auth = new Auth();

            ObjectMapper mapper = new ObjectMapper();
            try {
                auth = mapper.readValue(jsonString, Auth.class);
            } catch (JsonGenerationException jge) {
                jge.printStackTrace();
            } catch (JsonMappingException jme) {
                jme.printStackTrace();
            } catch (JsonParseException jpe) {
                jpe.printStackTrace();
            } catch (IOException io) {
                io.printStackTrace();
            }

            if (auth.getSignature().equals(signature)) {
               Response response =xxx.getStep(auth);
               return Util.genJson(response, auth);
            }              
        }
        return null;
    }

Auth

@Data
public class Auth {

    @JsonIgnore
    private String cipher;

    @JsonIgnore
    private String month;

    @JsonIgnore
    private String signature;

    // need to return these two as json
    private String pay_resp_resp_code;
    private String pay_resp_desc;

}

After add @JsonIgnore, signature become null

how is the mapper supposed to know what attributes to encode and which not to encode? — Philipp Sander, Aug 09 '18 at 15:42
Is there a way to let the mapper know which attributes should be made ? — Hoo, Aug 09 '18 at 15:44
what library do you use to create the json? Some use the `@transient`annotation to know which variable should be ignored — jhamon, Aug 09 '18 at 15:45
I assume you're using Jackson: https://www.baeldung.com/jackson-ignore-properties-on-serialization — Philipp Sander, Aug 09 '18 at 15:45
yes you can use `@JsonProperty(access = Access.WRITE_ONLY) private String password;` this for all other three fields — Ryuzaki L, Aug 09 '18 at 15:45
Have you tried using `@JsonIgnore` annotation on some of the fields in your Auth.java? You might find it helpful. — Lai, Aug 09 '18 at 15:46

score 1 · Accepted Answer · answered Aug 09 '18 at 15:48

1

If you are using jackson 1.9 below version

  Add @IgnoreJson annotation on Getter method

If you are using newer version of jackson

@JsonProperty(access = Access.WRITE_ONLY) 
private String password;

answered Aug 09 '18 at 15:48

Ryuzaki L

37,302
12
68
98

Selindek · Answer 2 · 2018-08-09T15:55:17.310

1

If all the other properties in the Auth object are null then this could help:

mapper.setSerializationInclusion(Include.NON_NULL);

If the other properties (or some of them) are primitives then you have to annotate them with the

@JsonIgnore

annotation.

Or... if you cannot change/edit the Auth object then simply create an other private object which contains only the required properties.

edited Aug 09 '18 at 15:55

answered Aug 09 '18 at 15:50

Selindek

3,269
1
18
25

1

It seems that you use the same Auth object for the incoming and also for the outgoing message however some of the properties are used only in the request others only in the response. Use the @JsonProperty(access = Access.WRITE_ONLY) and @JsonProperty(access = Access.WRITE_READ) annotations. Or create two separate objects: AuthIn and AuthOut, each one only with the required properties. I prefer this latter solution, it's much more clear. – Selindek Aug 09 '18 at 16:33

Return object as Json in java

2 Answers2