Pretty printing JSON from Jackson 2.2's ObjectMapper

Question

Right now I have an instance of org.fasterxml.jackson.databind.ObjectMapper and would like to get a String with pretty JSON. All of the results of my Google searches have come up with Jackson 1.x ways of doing this and I can't seem to find the proper, non-deprecated way of doing this with 2.2. Even though I don't believe that code is absolutely necessary for this question, here's what I have right now:

ObjectMapper mapper = new ObjectMapper();
mapper.setSerializationInclusion(Include.NON_NULL);
System.out.println("\n\n----------REQUEST-----------");
StringWriter sw = new StringWriter();
mapper.writeValue(sw, jsonObject);
// Want pretty version of sw.toString() here

gregwhitaker · Accepted Answer · 2013-07-12T15:07:58.757

309

You can enable pretty-printing by setting the SerializationFeature.INDENT_OUTPUT on your ObjectMapper like so:

mapper.enable(SerializationFeature.INDENT_OUTPUT);

edited Jul 12 '13 at 15:07

answered Jul 12 '13 at 14:59

gregwhitaker

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I have also tried this but it seems that `SerializationConfig` is resolved but `SerializationConfig.Feature` is not. This seems to be another method of pretty printing that's also deprecated unless I'm missing something. There is a `Feature` class that's separated out on its own, but does not have an `INDENT_OUTPUT` constant inside. :( – Anthony Atkinson Jul 12 '13 at 15:02
Excellent! I'd love to know how you found that ;) – Anthony Atkinson Jul 12 '13 at 15:15
2

I looked at one of my projects, but it appears that it is also here: https://github.com/FasterXML/jackson-databind under "Commonly used Features" – gregwhitaker Jul 12 '13 at 15:18
The relevant import needed is import com.fasterxml.jackson.databind.{SerializationFeature, ObjectMapper} – dgh Aug 26 '13 at 06:49
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on 2.2.1 this is what it took for me: import org.codehaus.jackson.map.SerializationConfig.Feature; mapper.enable(Feature.INDENT_OUTPUT); – harschware Dec 16 '13 at 20:31
This did not work for with the 2.5.3 api, I've added the updated api call in my answer – Rian May 23 '15 at 09:45
ObjectMapper mapper = new ObjectMapper(); mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonObject)); – Learn More Jun 14 '22 at 09:38

score 52 · Answer 2 · edited Mar 05 '15 at 20:44

52

According to mkyong, the magic incantation is defaultPrintingWriter to pretty print JSON:

Newer versions:

System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonInstance));

Older versions:

System.out.println(mapper.defaultPrettyPrintingWriter().writeValueAsString(jsonInstance));

Seems I jumped the gun a tad quickly. You could try gson, whose constructor supports pretty-printing:

Gson gson = new GsonBuilder().setPrettyPrinting().create();
String jsonOutput = gson.toJson(someObject);

Hope this helps...

edited Mar 05 '15 at 20:44

NicolasMoise

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answered Jul 12 '13 at 14:38

hd1

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I found this article and was disappointed to find that this is one of those deprecated ways of pretty printing. `defaultPrettyPrintingWriter()` is no longer available (even as a deprecated method) on the `ObjectMapper` class. – Anthony Atkinson Jul 12 '13 at 14:39
I was actually thinking about doing this, but my application is already heavily Jackson-oriented and all of the functionality is actually complete. The web application server that this will be hosted on is already being taxed pretty heavily, and I wouldn't want to load extra libraries simply for logging requests and responses. I will definitely up-vote your answer, though. – Anthony Atkinson Jul 12 '13 at 14:59
8

@AnthonyAtkinson in Jackson 2.3 there is a method `ObjectMapper.writerWithDefaultPrettyPrinter()` – matt b Jan 21 '14 at 22:41

score 39 · Answer 3 · answered May 23 '15 at 09:41

39

The jackson API has changed:

new ObjectMapper()
.writer()
.withDefaultPrettyPrinter()
.writeValueAsString(new HashMap<String, Object>());

answered May 23 '15 at 09:41

Rian

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It’s still possible (with Jackson 2.7.6) to use `new ObjectMapper().configure(SerializationFeature.INDENT_OUTPUT, true).writer().writeValueAsString(new HashMap());`. You just have to make sure to use the writer you get from the configured `ObjectMapper`. – Martin Jul 11 '17 at 14:04

score 4 · Answer 4 · answered Mar 18 '15 at 17:28

the IDENT_OUTPUT did not do anything for me, and to give a complete answer that works with my jackson 2.2.3 jars:

public static void main(String[] args) throws IOException {

byte[] jsonBytes = Files.readAllBytes(Paths.get("C:\\data\\testfiles\\single-line.json"));

ObjectMapper objectMapper = new ObjectMapper();

Object json = objectMapper.readValue( jsonBytes, Object.class );

System.out.println( objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString( json ) );
}

Saved my day @Stan. Wish I could give a million upvotes ! – Ajay Kumar Sep 04 '22 at 04:08 — Ajay Kumar, Sep 04 '22 at 04:08

score 0 · Answer 5 · answered Apr 10 '15 at 02:17

If you'd like to turn this on by default for ALL ObjectMapper instances in a process, here's a little hack that will set the default value of INDENT_OUTPUT to true:

val indentOutput = SerializationFeature.INDENT_OUTPUT
val defaultStateField = indentOutput.getClass.getDeclaredField("_defaultState")
defaultStateField.setAccessible(true)
defaultStateField.set(indentOutput, true)

score 0 · Answer 6 · answered Mar 09 '16 at 06:31

if you are using spring and jackson combination you can do it as following. I'm following @gregwhitaker as suggested but implementing in spring style.

<bean id="objectMapper" class="com.fasterxml.jackson.databind.ObjectMapper">
    <property name="dateFormat">
        <bean class="java.text.SimpleDateFormat">
            <constructor-arg value="yyyy-MM-dd" />
            <property name="lenient" value="false" />
        </bean>
    </property>
    <property name="serializationInclusion">
        <value type="com.fasterxml.jackson.annotation.JsonInclude.Include">
            NON_NULL
        </value>
    </property>
</bean>

<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject">
        <ref bean="objectMapper" />
    </property>
    <property name="targetMethod">
        <value>enable</value>
    </property>
    <property name="arguments">
        <value type="com.fasterxml.jackson.databind.SerializationFeature">
            INDENT_OUTPUT
        </value>
    </property>
</bean>

score 0 · Answer 7 · answered Feb 01 '20 at 00:41

If others who view this question only have a JSON string (not in an object), then you can put it into a HashMap and still get the ObjectMapper to work. The result variable is your JSON string.

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.HashMap;
import java.util.Map;

// Pretty-print the JSON result
try {
    ObjectMapper objectMapper = new ObjectMapper();
    Map<String, Object> response = objectMapper.readValue(result, HashMap.class);
    System.out.println(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(response));
} catch (JsonParseException e) {
    e.printStackTrace();
} catch (JsonMappingException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

score -8 · Answer 8 · edited Feb 26 '15 at 05:34

-8

Try this.

 objectMapper.enable(SerializationConfig.Feature.INDENT_OUTPUT);

edited Feb 26 '15 at 05:34

Mayank Jain

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answered Feb 26 '15 at 04:37

Nagappa L M

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Duplicating the chosen answer after 7 months is not really helpful. – Igor Rodriguez Mar 02 '15 at 13:39
1

might helpful to some one as i mentioned in one line,i feel good in sharing whatever i am knowing. – Nagappa L M Mar 04 '15 at 03:16

Pretty printing JSON from Jackson 2.2's ObjectMapper

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