grails动态调用方法

见例子：就在这一行：operationImplService."${processAction}"(params1,params2)

def operationImplService
    def test() {
        def processAction = "dm"
        def postResult = operationImplService."${processAction}"('abc')
        println "postResult:"+postResult
    }
}
class OperationImplService {
    def dm(String param) {
        println "调用我了，参数：${param}"
        return true
    }
}      

def arg = [1,2]
def tools = new Tools()
println tools."max"(*arg)