比如有一個public class UserServiceImpl (){private User u;//這里帶構造函數 并且有參數public UserServiceImpl (User u){this.u=u;}}public class TestController(){//這里怎么實例化上面的service//我想把參數傳給service的構造函數@Autowiredprivate UserServiceImpl service;  @RequestMapping("/save")public @ResponseBodyString save(User u){//這里通過瀏覽器輸入傳過來一個User對象//如何把這個User對象傳給上述servicereturn "saved";}}