Spring Security代码中获取认证之后用户数据

@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String hello() {
      Authentication authentication = SecurityContextHolder
        .getContext().getAuthentication();
      User principal = (User) authentication.getPrincipal();
      System.out.println("身份 :"+principal.getUsername());
      System.out.println("凭证 :"+authentication.getCredentials());
      System.out.println("权限 :"+authentication.getAuthorities());
      return "hello security";
    }
}