JSONPath

JSON-JEP integrates the Jayway JsonPath implementation to natively work with the JSON-JEP API. There are two ways to execute a JsonPath query:

• Using the JSONPathFactory to compile and create a JSONPath instance
• Using the select*() functions on either the JSONObject or JSONArray interfaces.

Using the JSONPathFactory

The JSONPathFactory allows you to create a JSONPath instance by compiling a JSONPath expression, then executing the query against a JSONNode instance (either a JSONObject or JSONArray). Once the JSONPath instance is created, you can execute a query using one of the select* methods:

• JSONArray select(JSONNode context) : apply the compiled JsonPath query to the current JSONNode. Returns a JSONArray of zero or more results
• <T> T selectValue(JSONNode context) : Return a typed value from the query

The JSONPathFactory includes two methods:

• static JSONPath compile(String jsonPath, Option... options)
• static JSONPath compile(String jsonPath, Criteria criteria, Option...options)

The following is an example of using the JSONPathFactory

/*
JSONObject obj = ... (see the Getting Started page for how to initialize a JSONObject
*/
JSONPath jsonPath = JSONPathFactory.compile("$.store.book[*].author");
JSONArray results = jsonPath.select(obj);
results.spliterator()... //stream out the values;

Likewise, you can get a single value using the selectValue(JSONNode) context:

JSONPath jsonPath = JSONPathFactory.compile("$.store.book[0].author");
String author = jsonPath.selectValue(obj);

Using the select* methods directly from a JSONNode

The JSONNode interface includes several select* methods which assumes that the current node is the context from which to apply the JsonPath query.

final JSONNode node = ParserFactory.getParser().parse(getClass().getResourceAsStream("/us-reps.json"));

final JSONArray dems = node.select("$.objects[?(@.party=='Democrat')]");
final JSONArray gop = node.select("$.objects[?(@.party=='Republican')]");

JSONObject jaredPolis = dems.selectValue("$.*[?(@.person.lastname=='Polis')]");
System.out.println(jaredPolis.prettyPrint());