Create Json String manually

Question

I'm trying to create a Json structure manually in Java. In the end, I need the a string representation of my Json object. Since my project already has a dependency to GSON, I wanted to use this. But after several hours of trying and googling, I think, I completely misunderstand something.

At the moment, I have the following (non-working) code:

JsonObject user_auth = new JsonObject();
user_auth.addProperty("user_name", username);
user_auth.addProperty("password", password);
JsonObject rest_data = new JsonObject();
Gson gson = new Gson();
rest_data.addProperty("user_auth", gson.toJson(user_auth));
rest_data.addProperty("application", APPLICATION_NAME);
String payload = gson.toJson(rest_data);

The problem I'm facing is that the "user_auth" element gets escaped quotes (\" instead of " when it is added to the outer element. How can I prevent this? I also tried to use

rest_data.addProperty("user_auth", user_auth.toString());

but this did exactely the same.

Regards,

You're doubly-encoding your JSON. Just add user_auth directly to the enclosing JsonObject, don't JSONify it. — Hot Licks
– Hot Licks, Commented Jan 3, 2014 at 13:12
(Before you do the toJson call your entire object structure should toString to look almost exactly like the intended JSON result.) — Hot Licks
– Hot Licks, Commented Jan 3, 2014 at 13:14
(Converting JSON to and from Maps/Lists is perfectly natural and uncomplicated. Stuff like Jackson makes it more complicated, not less.) — Hot Licks
– Hot Licks, Commented Jan 3, 2014 at 13:16
Hot Licks' comment should be an answer, and accepted, as it solves OP's question concisely and completely without editorial comment. (Just remove the "toJson" from user_auth, win!) — tekHedd
– tekHedd, Commented Feb 27, 2023 at 23:33

fluminis · Accepted Answer · 2014-01-03 13:39:19Z

13

Writing the JSON manually is not a good solution.

It seems that you encode user_auth twice.

Try this instead:

JsonObject user_auth = new JsonObject();
user_auth.addProperty("user_name", username);
user_auth.addProperty("password", password);

JsonObject rest_data = new JsonObject();
rest_data.addProperty("user_auth", user_auth);
rest_data.addProperty("application", APPLICATION_NAME);

Gson gson = new Gson();
String payload = gson.toJson(rest_data);

answered Jan 3, 2014 at 13:39

fluminis

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1 Comment

tekHedd Over a year ago

Strong disagree. Writing JSON manually is frequently a good solution. Asserted without evidence, dismissed without evidence.

Eugene Lebedev · Accepted Answer · 2018-01-21 10:20:51Z

1

Another way is directly convert POJO into JSON.

1. Create POJO object

i.e. user class:

class User {

    @JsonProperty("user_name") // this annotation helps you to specify
                               // property name in result json
    private String userName;

    @JsonProperty("first_name")
    private String firstName;

    // ...

    // getters and setters here, hashcode, equals, etc.

}

2. Convert POJO to JSON string

for example:

User user = new User("superlogin", "superpass", ...);

String jsonString = new Gson().toJson(user);

Thats all :)

I think it's more convenient way than build json structure manually.

edited Jan 21, 2018 at 10:20

answered Jan 21, 2018 at 10:14

Eugene Lebedev

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Andre Leon Rangel · Accepted Answer · 2017-09-20 14:15:36Z

0

Use the addProperty() for the user_auth and then for the rest_data you need the payload.

String payloadJSON = gson.toJson(rest_data);

answered Sep 20, 2017 at 14:15

Andre Leon Rangel

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Arun · Accepted Answer · 2017-07-27 15:16:50Z

-2

If you dont wont to add external jar then, try this

return "{UPLOAD:"+upload+",UPLOADSTATUS:"+perUpload+",TRANSCODE:"+transcode+",TRANSCODESTATUS:"+transcodestatus+"}";

answered Jul 27, 2017 at 15:16

Arun

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1 Comment

Eugene Lebedev Over a year ago

bad advice in long term, imagine if you have 20 properties and 10 entities with manual to-json method (as you suggest). one day you need to add new 5 properties for each object. it's kinda little hell

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