Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Relaxed JSON parsing

DZone's Guide to

Relaxed JSON parsing

· Java Zone ·
Free Resource

Get the Edge with a Professional Java IDE. 30-day free trial.

JSON is a good alternative when you need a lightweight format to specify structured data. But sometimes (for example when you want the user to specify JSON manually) you would like to relax the formalism required to specify “valid” JSON data. For example the following snippet is not valid as per the spec, although its intent is quite clear:

[{ foo: 'bar' }]

To make this standard compliant we would need to write it as:

[{ "foo": "bar" }]

We shouldn’t run out and blame the standard of course since it needs to balance many contradictory requirements (ambiguity of encoded data, ease of understanding, ease of writing parsers, etc). If you decide that you want to strike the balance differently (make the definition of valid data more relaxed) you can do this easily with the Jackson parser:

JsonParser parser = new JsonFactory()
	.createJsonParser("[{ foo: 'bar' }]")
		.enable(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES)
		.enable(JsonParser.Feature.ALLOW_SINGLE_QUOTES);
JsonNode root = new ObjectMapper().readTree(parser);
 
assertEquals("bar", root.get(0).get("foo").asText());

If your tool of choice is gson, it is slightly more complicated but still doable. See the linked source code for a complete example.

JSON is a good tool for semi-structured data and using a relaxed parsing can make the programs you write easier to use.

 

From http://www.transylvania-jug.org/archives/324

Get the Java IDE that understands code & makes developing enjoyable. Level up your code with IntelliJ IDEA. Download the free trial.

Topics:

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}