import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

@Controller
public class HelloController {
    
    /**
     * 转发形式
     * @param name
     * @param model
     * @return
     */
    @RequestMapping("/helloForward")
    public String helloForward(@RequestParam(value="name", required=false, defaultValue="World2017") String name, Model model) {
        model.addAttribute("name", name);
        return "hello";
    }
    
    
    
    @RequestMapping("/hello")
    public String hello() {        
        return "hello";       
    }
    
    /**
     * 使用RedirectAttributes类
     * @param name
     * @param redirectAttributes
     * @return
     */
    @RequestMapping("/helloRedirect")
    public String helloRedirect(@RequestParam(value="name", required=false ) String name, RedirectAttributes redirectAttributes) {
       
        redirectAttributes.addFlashAttribute("name", name);
        
        return "redirect:/hello";
    }
    
    
    @RequestMapping("/hello2")
    public String hello2(Model model,HttpServletRequest request) {
        
        HttpSession session = request.getSession();
        model.addAttribute("name",session.getAttribute("name"));
        return "hello";      
    }
    
    /**
     * 常规做法，重定向之前把参数放进Session中，在重定向之后的controller中把参数从Session中取出并放进ModelAndView
     * @param name
     * @param request
     * @return
     */
    @RequestMapping("/helloRedirect2")
    public String helloRedirect2(@RequestParam(value="name", required=false ) String name, HttpServletRequest request) {
       
        request.getSession().setAttribute("name", name);
        
        return "redirect:/hello2";
    }
    
    
}