json-path/src/main/java/io/restassured/path/json/JsonPath.java
public JsonPath param(String key, Object value) {
        JsonPath newP = new JsonPath(this, config);
        if (newP.params == null) {
            newP.params = new HashMap<String, Object>();
        }
        newP.params.put(key, value);
        return newP;
    }
public JsonPath param(String key, Object value) {
        JsonPath newP = new JsonPath(this, config);
        if (newP.params == null) {
            newP.params = new HashMap<String, Object>();
        }
        newP.params.put(key, value);
        return newP;
    }
Add a parameter for the expression. Example:
<pre>
String name = System.console().readLine();
List&lt;Map&gt; books = with(Object).param("name", name).get("store.book.findAll { book -> book.author == name }");
</pre>

@param key   The name of the parameter. Just use this name in your expression as a variable
@param value The value of the parameter
@return New JsonPath instance with the parameter set