Jackson – How to enable pretty print JSON output

In Jackson, we can use writerWithDefaultPrettyPrinter() to pretty print the JSON output.

Tested with Jackson 2.9.8

1. Pretty Print JSON

1.1 By default, Jackson print in compact format:

	ObjectMapper mapper = new ObjectMapper();
	Staff staff = createStaff();
	String json = mapper.writeValueAsString(staff);
	System.out.println(json);

Output

{"name":"favtuts","age":38,"skills":["java","python","node","kotlin"]}

1.2 To enable pretty print on demand.

	ObjectMapper mapper = new ObjectMapper();
	Staff staff = createStaff();
	// pretty print
	String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(staff);
	System.out.println(json);

Output

{
  "name" : "favtuts",
  "age" : 38,
  "skills" : [ "java", "python", "node", "kotlin" ]
}

1.3 To enable pretty print globally.

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

	// pretty print
	ObjectMapper mapper = new ObjectMapper().enable(SerializationFeature.INDENT_OUTPUT);
	Staff staff = createStaff();
	String json = mapper.writeValueAsString(staff);
	System.out.println(json);

Output

{
  "name" : "favtuts",
  "age" : 38,
  "skills" : [ "java", "python", "node", "kotlin" ]
}

Note

To display the pretty print JSON output on an HTML page, wraps it with pre tags.

<pre>${pretty-print-json-output}</pre>

Note – 12/12/2013

The article is updated to use writerWithDefaultPrettyPrinter(), the old defaultPrettyPrintingWriter() is deprecated.

References

• Jackson – How to parse JSON
• Gson – How to enable pretty print JSON output