spring-mvc - Spring MVC CRUD Controller 最佳实践

Question

我正在尝试为 Spring MVC 简单 CRUD Controller 找到最佳实践方法。网络上和本论坛上都有很多 CRUD Controller 的示例，但大多数都存在以下两个问题之一:

保存/或更新或删除后，它们会显示保存和更新发生的消息，但它们点击的 URL 上仍然有“/update/{id}”或“/delete/{id}”。这是“错误的”，因为显示的内容通常是对象列表。

或者

Controller 重定向到“showAll” View ，但是没有消息表明发生了操作，这对用户不友好。

有没有人有一个没有这两个问题的 crud Controller 的例子？

谢谢，

亨利

@Controller
@RequestMapping(value="/role")
public class RoleController {
    private static final Logger log = Logger.getLogger(RoleController.class);

    @Autowired
    private RoleValidator validator = null;
    @Autowired
    private RoleService service = null;


    public void setService(RoleService  service) {
        this.service = service;
    }

    public void setValidator(RoleValidator validator) {
        this.validator = validator;
    }


    @RequestMapping(method=RequestMethod.GET)
    public String showForm(ModelMap model){
        List<Role> domainObjectList = service.getRoles();
        model.addAttribute("domainObjectList", domainObjectList);
        return "role";
    }

    @RequestMapping(value="/add", method=RequestMethod.GET)
    public String preAdd(ModelMap model){
        Role domainObject = new Role();
        model.addAttribute("domainObject", domainObject);
        addConstrainedFields(model);
        return "roleEdit";
    }

    @RequestMapping(value="/add", method=RequestMethod.POST)
    public ModelAndView add(@ModelAttribute(value="domainObject") Role domainObject, BindingResult result) {
        validator.validate(domainObject, result);
        ModelAndView mv = new ModelAndView("role");
        if(result.hasErrors()){
            mv = new ModelAndView("roleEdit");
            mv.addObject("domainObject", domainObject);
            return mv;
        }
        service.insertRole( domainObject );
        mv.addObject("domainObjectList", service.getRoles());
        mv.addObject("messageKey","label.form.item.added");
        //PROBLEM: the URL will remain "/add", but the content will be one of showing all roles + message that role was added. 
        return mv;
    }

    @RequestMapping(value="/update/{id}")
    public String preUpdate(@PathVariable Integer id, ModelMap model) {
        Role domainObject = service.getRole( id );
        model.addAttribute("domainObject", domainObject);
        return "roleEdit";
    }


    @RequestMapping(value="/update", method=RequestMethod.POST)
    public String update(@ModelAttribute(value="domainObject") Role domainObject, ModelMap model, BindingResult result){
        validator.validate(domainObject, result);
        ModelAndView mv = new ModelAndView("role");
        if(result.hasErrors()){        
            model.addAttribute("domainObject", domainObject);
            return "roleEdit";
        }
        service.insertRole(domainObject);
        model.addAttribute("messageKey","label.form.item.added");
        model.addAttribute("domainObjectList", service.getRoles());
        //PROBLEM: the message that the object was updated will be lost, but the URL will be /role and we will show all roles.
        return "redirect:/role";
    }

    @RequestMapping(value="/delete/{id}")
    public String delete(@PathVariable Integer id, ModelMap model) {
        Role domainObject = service.getRole( id );
        if (domainObject == null) {
            model.addAttribute("messageKey","label.form.item.notfound");
            return showForm(model);
        }
        service.deleteRole(domainObject);
        model.addAttribute("messageKey","label.form.item.deleted");
        return showForm(model);
    }

    @RequestMapping(value="/delete", method=RequestMethod.POST)
    public ModelAndView delete(@ModelAttribute(value="domainObject") Role domainObject, BindingResult result){
        validator.validate(domainObject, result);
        ModelAndView mv = new ModelAndView("role");
        if(!result.hasErrors()){
            service.deleteRole(domainObject);
            mv.addObject("messageKey","label.form.item.deleted");
            domainObject = new Role();
            mv.addObject("domainObject", domainObject);
        }
        mv.addObject("domainObjectList", service.getRoles());
        return mv;
    }

}

Answer 1

您应该使用 RESTful URL 设计，使用 get 读取，post 来创建，put 到更新，delete 到删除。使用 HiddenHttpMethodFilter对于不 PUT 或 DELETE 的用户代理。

使用 Post-Redirect-Get避免重新发布的模式。

使用 Flash Attributes在后续页面上显示成功/失败消息。