It is not possible to retrieve the value of a method input parameter.
For annotation the parameters can be read:
MATCH (c:Class)-[:DECLARES]->()-[:ANNOTATED_BY]->(an:Annotation)-[:OF_TYPE]->(:Type{name:"RequestMapping"})
MATCH (an)-[:HAS]->(:Value{name:"value"})-[:CONTAINS]->(v:Value)
What is the best approach to retrieve the value of an input method of a class method?