我正在使用 google golang reset 服務(wù)，當(dāng)我嘗試運行此代碼時，post 方法出現(xiàn)問題，它顯示 post 數(shù)據(jù)未定義    package mainimport (    "code.google.com/p/gorest"    "fmt"    "net/http")type Invitation struct {    User string}//Service Definitiontype HelloService struct {    gorest.RestService    //gorest.RestService `root:"/tutorial/"`    helloWorld gorest.EndPoint `method:"GET" path:"/hello-world/" output:"string"`    sayHello   gorest.EndPoint `method:"GET" path:"/hello/{name:string}" output:"string"`    posted     gorest.EndPoint `method:"POST" path:"/post/"  postdata:"User" `}func main() {    gorest.RegisterService(new(HelloService)) //Register our service    http.Handle("/", gorest.Handle())    http.ListenAndServe(":8787", nil)}func (serv HelloService) Posted(posted User) {    fmt.Println(User)}func (serv HelloService) HelloWorld() string {    return "Hello World"}func (serv HelloService) SayHello(name string) string {    return "Hello " + name}這是我得到的錯誤# command-line-arguments./registation.go:28: undefined: User./registation.go:29: undefined: User請幫忙解決這個問題