I want to insert a set of values and display a list of inserted data on the same page. What should I do in the controller class?

Here are all my codes

UserController.java

    package com.crud.controll;
    
    import com.crud.model.UserEntity;
    import com.crud.service.UserDao;
    import java.util.List;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    
    
    @Controller
    public class UserController {
        
        private final UserDao userDao;
    
        public UserController(UserDao userDao) {
            super();
            this.userDao = userDao;
        }
        
        
        
        @GetMapping("/home")
        public String Home(Model model){
            
            List<UserEntity> users = userDao.findBookAll();
            model.addAttribute("users", users);
            model.addAttribute("userForm", new UserEntity());
            return "display";
        }
    
    
    
    @PostMapping("/home")
    public String createUser(@ModelAttribute UserEntity userEntity, Model model) {
        
        userDao.createANewUser(userEntity);
        
        return "display";
    }
}

So, this is the page that i want

enter image description here

CodePudding user response：

I think it will be easy if you update your method as follows:

   @GetMapping("/home")
    public Model Home(Model model){
        
        List<UserEntity> users = userDao.findBookAll();
        model.addAttribute("users", users);
        model.addAttribute("userForm", new UserEntity());
        return model;
    }

CodePudding user response：

I recommend Post/Redirect/Get pattern.

If you do not need info about inserted user use this:

@PostMapping("/home")
public String createUser(@ModelAttribute UserEntity userEntity, Model model) {
        
        userDao.createANewUser(userEntity);
        
        return "redirect:/home";
    }

If you need info about inserted user, you can use flash attributes:

@PostMapping("/home")
public RedirectView createUser(@ModelAttribute UserEntity userEntity, Model model, RedirectAttributes redirectAttributes) {
        
        userDao.createANewUser(userEntity);
        
        redirectAttributes.addFlashAttribute ("newUser", userEntity);

        return new RedirectView("/home", true);
    }

and in Home method use:

 @GetMapping("/home")
 public String Home(Model model, HttpServletRequest request){
            
            List<UserEntity> users = userDao.findBookAll();
            model.addAttribute("users", users);
            model.addAttribute("userForm", new UserEntity());


            Map<String, ?> inputFlashMap = 
            RequestContextUtils.getInputFlashMap(request);
            if (inputFlashMap != null) {
                UserEntity newUser = (UserEntity) inputFlashMap.get("newUser");
                model.addAttribute("newUser", newUser);
            }
 
            return "display";
        }

Or you can put newUser into userForm property to fill out form.

More info about flash attributes: Link. Maybe there is even nicer way to extract flash attributes in Home method.