Java / Spring model forms framework_问答_开发者

开发者 https://www.devze.com 2023-02-14 12:36 出处：网络

Is there any model/entity form abstraction library available i can use in Spring projects ? I\'m looking something like \"Django forms framework\" or \"Symfony Forms\" in the Java/Spring world.

Is there any model/entity form abstraction library available i can use in Spring projects ?

I'm looking something like "Django forms framework" or "Symfony Forms" in the Java/Spring world.

The basic idea is to simplify JPA开发者_如何学编程 entities form creation and the easier creation of multiform handling controllers.

If i've understood you correctly you're after a way to bind an entity to a form (and allow a user to add/edit entities)? In which case theres no need for another framework Spring already does this really well. A quick example:

Our controller would look like this:

@Controller
@RequestMapping(value = "/addUser.html")
public class UserController {

  @Autowired
  private UserAccountService service;

  @Autowired
  @Qualifier("userValidator")
  private Validator userValidator;

  @ModelAttribute("user")
  public User getBackingObject() {
    //This gets the object we're letting the user edit.
    //This can be any POJO so a JPA entity should be fine.
    //Note that we're creating an object here but we could 
    //just as easily fetch one we already have from a database/service etc
    return new User();
  }

  @RequestMapping(method = RequestMethod.GET)
  public String showForm() {
    //The form to present to the user
    return "/addUser";
  }

  @RequestMapping(method = RequestMethod.POST)
  //note: here Spring has automatically bound the entries that have been input into the webform into the User param supplied here
  protected String onSubmit(User user, Errors errors, HttpServletRequest request) {

    userValidator.validate(user, errors);
    if (errors.hasErrors()) {
      //The validator showed up some errors so send the object back to let the user correct it
      return "/addUser";
    }

    //save our new user
    service.saveUser(user);

    //best practice is to redirect to another view to make sure the backing object is cleared
    return "redirect:/success.html";
  }

}

Then we can use spring form macros in our JSP to create the form:

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<title>Add a user</title>
</head>
<body>

<form:form commandName="user">
  <label for="firstname">first name</label> 
  <form:input path="firstname" /> <form:errors cssClass="errorText" path="firstname" />
  <label for="lastname">last name</label> 
  <form:input path="lastname" /> <form:errors cssClass="errorText" path="lastname" />
  <input type="submit" value="Save" />
</form:form>
</body>
</html>

I think spring roo does what you want to do.