编辑代码

import groovy.json.*
class ReqParam{
    String billingCode
}
def paramConvert(param){
    def json = new JsonSlurper()
    println param
    println param.getClass()
    def keys = param.keySet()
    def reqParam = new ReqParam(billingCode:keys[0])
    return JsonOutput.toJson(reqParam)
}