how to Validate if JSON Path Exists in JSON - json

Question

In a given json document, how to validate if a json path exists ?
I am using jayway-jsonpath and have the below code
JsonPath.read(jsonDocument, jsonPath)
The above code can potentially throw below exception
com.jayway.jsonpath.PathNotFoundException: No results for path:
$['a.b.c']
In order to mitigate it, I intend to validate if the path exists before trying to read it with JsonPath.read
For reference I went through the following 2 documentations, but couldn't really get what I want.
http://www.baeldung.com/guide-to-jayway-jsonpath
https://github.com/json-path/JsonPath

Answer 1

Whilst it is true that you can catch an exception, like it is mentioned in the comments there might be a more elegant way to check if a path exists without writing try catch blocks all over the code.
You can use the following configuration option with jayway-jsonpath:
com.jayway.jsonpath.Option.SUPPRESS_EXCEPTIONS
With this option active no exception is thrown. If you use the read method, it simply returns null whenever a path is not found.
Here is an example with JUnit 5 and AssertJ showing how you can use this configuration option, avoiding try / catch blocks just for checking if a json path exists:
#ParameterizedTest
#ArgumentsSource(CustomerProvider.class)
void replaceStructuredPhone(JsonPathReplacementArgument jsonPathReplacementArgument) {
DocumentContext dc = jsonPathReplacementHelper.replaceStructuredPhone(
JsonPath.parse(jsonPathReplacementArgument.getCustomerJson(),
Configuration.defaultConfiguration().addOptions(Option.SUPPRESS_EXCEPTIONS)),
"$.cps[5].contactPhoneNumber", jsonPathReplacementArgument.getUnStructuredPhoneNumberType());
UnStructuredPhoneNumberType unstructRes = dc.read("$.cps[5].contactPhoneNumber.unStructuredPhoneNumber");
assertThat(unstructRes).isNotNull();
// this path does not exist, since it should have been deleted.
Object structRes = dc.read("$.cps[5].contactPhoneNumber.structuredPhoneNumber");
assertThat(structRes).isNull();
}

Answer 2

You can also create a JsonPath object or ReadContext with a Configuration if you have a use case to check multiple paths.
// Suppress errors thrown by JsonPath and instead return null if a path does not exist in a JSON blob.
Configuration suppressExceptionConfiguration = Configuration
.defaultConfiguration()
.addOptions(Option.SUPPRESS_EXCEPTIONS);
ReadContext jsonData = JsonPath.using(suppressExceptionConfiguration).parse(jsonString);
for (int i = 0; i < listOfPaths.size(); i++) {
String pathData = jsonData.read(listOfPaths.get(i));
if (pathData != null) {
// do something
}