springmvc 中 request.getAttribute("XXX")断点执行两次

java代码:

@Controller
public class TestController {
    @RequestMapping("test")
    public String test(HttpServletRequest request,
            HttpSession session,
            HttpServletResponse response, Model model){
//      System.out.println("11111111111111111");
        System.out.println("22222222222222222");
        Customer customer = (Customer) request.getAttribute(
                "customer");
        return "tml/common/voucher";
    }
}

断点打在
Customer customer = (Customer) request.getAttribute("customer");,
但是打印信息只打印了一次!