一、跳转
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping; @Controller
public class Login{ /**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";
}
}
另外forward跳转后地址栏URL不会改变 而redirect会改变
二、传参
@RequestMapping(value = "update", method = RequestMethod.POST)
public String update(@Valid @ModelAttribute("user") User user,
RedirectAttributes redirectAttributes) {
accountService.updateUser(user);
redirectAttributes.addFlashAttribute("message", "更新用户" + user.getLoginName() + "成功");
return "redirect:/admin/user";
}
为了防止用户刷新重复提交，save操作之后一般会redirect到另一个页面，同时带点操作成功的提示信息。因为是Redirect，Request里的attribute不会传递过去，如果放在session中，则需要在显示后及时清理，不然下面每一页都带着这个信息也不对。Spring在3.1才提供了这个能力，原理是放到session中，session在跳到页面后马上移除对象。所以你刷新一下后这个值就会丢掉。