/**转发**/ 

@RequestMapping("/login.do")

public String login(HttpServletRequest request,HttpServletResponse response){

request.setAttribute("message", "hello");

return "forward:/index.do"; //forward在跳转后可以取到message值

}

@RequestMapping("/index.do")

public String index(HttpServletRequest request,HttpServletResponse response){

return "welcome";

}

/**重定向**/

@RequestMapping("/logout.do")

public String logout(HttpServletRequest request,HttpServletResponse response){

request.setAttribute("message", "hello");

return "redirect:/register.do"; //redirect在跳转后无法取到message值

}

@RequestMapping("/register.do")

public String register(HttpServletRequest request,HttpServletResponse response){

return "register";

}

@RequestMapping(“/update.do”)

public String update( RedirectAttributes redirectAttributes) {

redirectAttributes.addFlashAttribute("message", "操作成功");

return "redirect:/admin/user";

}