How do I pretty-print existing JSON data with Java?

Question

I have a compact JSON string, and I want to format it nicely in Java without having to deserialize it first -- e.g. just like jsonlint.org does it. Are there any libraries out there that provides this?

A similar solution for XML would also be nice.

JSONObject has a `toString(int)` where you provide spacing for pretty printing. — Buhake Sindi, May 31 '11 at 09:14
@The Elite Gentleman: I would need to deserialize the JSON data to get a JSONObject, wouldn't I? — neu242, May 31 '11 at 10:26
@neu242, no, JSONObject is a JSON data already. Why do you want to do that? — Buhake Sindi, May 31 '11 at 10:29
I would look at Nashorn (part of a java installation). http://stackoverflow.com/questions/4105795/pretty-print-json-in-java#29094958 — jarry_dk, Jan 19 '17 at 10:11

Heath Borders · Answer 1 · 2014-10-28T13:10:57.203

97

int spacesToIndentEachLevel = 2;
new JSONObject(jsonString).toString(spacesToIndentEachLevel);

Using org.json.JSONObject (built in to JavaEE and Android)

edited Oct 28 '14 at 13:10

answered Oct 18 '14 at 17:57

Heath Borders

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What library does this use? As is it is not a very helpful answer. – Andrew Oct 28 '14 at 09:47
@Andrew Backer, this is not a library. As Heath Borders said, it is built into the Android libraries. I've tested this and it works perfectly without any libraries. – Tamby Kojak Nov 25 '14 at 08:11
1

Hm... I'm not developing for Android, and I don't deploy to a java EE container... hence the need for clarification. Thanks for adding that :) So for someone like me, distributing a java app targeting SE, it would be a library such as `org.json:json:20090211`? – Andrew Nov 26 '14 at 09:29
for those of us using Android, this is very useful and not really clear in the quick view of the docs. Didn't expect it to be built in. – manroe Jun 05 '15 at 22:40
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**`org.json.JSONObject` is not built into JavaEE**. The `JSON-P` library for `JsonObject` is `javax.json.JsonObject`. – Buhake Sindi Jul 11 '16 at 08:07
greattttt, this is very useful – dadan Oct 19 '17 at 03:15
The dependency with group ID of `org.json` and artifact ID of `json` in the Maven POM file or in your Gradle also supports prettifying JSON data by passing in the indent level in the `toString(int)` method. – tom_mai78101 May 15 '20 at 18:50
This is really useful in Spring Boot. – Arjun Sunil Kumar May 22 '20 at 14:23
this is very useful. but one problem. if data is large, all data not showing in. Any suggestion – Aminul Haque Aome Jun 10 '21 at 10:37

score 24 · Answer 2 · answered Jul 23 '17 at 13:24

Use gson. https://www.mkyong.com/java/how-to-enable-pretty-print-json-output-gson/

Gson gson = new GsonBuilder().setPrettyPrinting().create();
String json = gson.toJson(my_bean);

output

{
  "name": "mkyong",
  "age": 35,
  "position": "Founder",
  "salary": 10000,
  "skills": [
    "java",
    "python",
    "shell"
  ]
}

score 15 · Answer 3 · answered Aug 22 '17 at 15:36

15

Another way to use gson:

String json_String_to_print = ...
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
return gson.toJson(jp.parse(json_String_to_print));

It can be used when you don't have the bean as in susemi99's post.

answered Aug 22 '17 at 15:36

vcycyv

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Instantiating `JsonParser` is now deprecated. Use the static method `JsonParser.parseString(json_String_to_print)` instead. – kousen Oct 09 '19 at 22:31
This is the right answer let's up vote it !! – Dan Ortega Dec 17 '19 at 22:41
this must be accepted answer! – aligur Jul 29 '20 at 12:49

score 11 · Answer 4 · edited Jul 11 '16 at 08:06

11

If you are using jackson you can easily achieve this with configuring a SerializationFeature in your ObjectMapper:

com.fasterxml.jackson.databind.ObjectMapper mapper = new ObjectMapper();

mapper.configure(SerializationFeature.INDENT_OUTPUT, true);

mapper.writeValueAsString(<yourObject>);

Thats it.

edited Jul 11 '16 at 08:06

Buhake Sindi

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answered Feb 19 '14 at 16:00

Lars Rückemann

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score 4 · Accepted Answer · edited Sep 17 '13 at 15:17

4

I think for pretty-printing something, it's very helpful to know its structure.

To get the structure you have to parse it. Because of this, I don't think it gets much easier than first parsing the JSON string you have and then using the pretty-printing method toString mentioned in the comments above.

Of course you can do similar with any JSON library you like.

edited Sep 17 '13 at 15:17

Alois Mahdal

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answered May 31 '11 at 09:45

Waldheinz

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Links are broken. – Valentyn Kolesnikov Oct 18 '19 at 04:37

score 2 · Answer 6 · answered Aug 18 '16 at 08:09

I fount a very simple solution:

<dependency>
    <groupId>com.cedarsoftware</groupId>
    <artifactId>json-io</artifactId>
    <version>4.5.0</version>
</dependency>

Java code:

import com.cedarsoftware.util.io.JsonWriter;
//...
String jsonString = "json_string_plain_text";
System.out.println(JsonWriter.formatJson(jsonString));

Valentyn Kolesnikov · Answer 7 · 2021-03-16T17:45:01.657

2

Underscore-java library has methods U.formatJson(json) and U.formatXml(xml).

edited Mar 16 '21 at 17:45

answered Aug 17 '19 at 10:04

Valentyn Kolesnikov

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How do I pretty-print existing JSON data with Java?

7 Answers7

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