这是名为'abc‘的json文件。我想访问文件，然后我想访问a，b，c，d，e，f的值。如何在groovy语言中访问？

import groovy.json.JsonSlurper

def jsonText = '''
{
  "a": 1,
  "b": "hello",
  "c": true,
  "d": [1, 2, 3],
  "e": {
    "name": "John",
    "age": 30
  },
  "f": null
}
'''

def jsonSlurper = new JsonSlurper()
def json = jsonSlurper.parseText(jsonText)

def a = json.a
def b = json.b
def c = json.c
def d = json.d
def e = json.e
def f = json.f

println "a: $a"
println "b: $b"
println "c: $c"
println "d: $d"
println "e: $e"
println "f: $f"

a: 1
b: hello
c: true
d: [1, 2, 3]
e: [name:John, age:30]
f: null