Spring MVC + Hibernate - 从表单更新一些属性

Question

I have this controller:

@RequestMapping(value="admins", method=RequestMethod.POST, params="editar")
public String editarAdmin(@ModelAttribute("cadastroform") Usuario usuario){
    usuarioService.atualizaUsuario(usuario); //do the update
    return "redirect:/admin/admins?listar";
}

As you can see, I'm receiving the Usuario object and updating it, but, for that, I need to have this form on my jsp:

<sf:form id="formCadastrarAdmin" method="post" modelAttribute="cadastroform">
<label for="tfNome">Nome*: </label>
<sf:input path="nome" type="text" id="tfNome" name="nome" placeholder="Digite o nome do novo administrador"/>
<label for="tfEmail">E-mail*: </label>
<sf:input path="email" type="text" id="tfEmail" name="email" placeholder="Digite o email do novo administrador"/>

<c:choose>
    <c:when test="${!empty param.editar}">
        <sf:input path="login" type="hidden" id="tfLogin" name="login" placeholder="Digite o login do novo administrador"/>
        <sf:input path="senha" type="hidden" name="senha" placeholder="Digitar senha de acesso"/>
    </c:when>
    <c:otherwise>
        <label for="tfLogin">Login*:  </label>
        <sf:input path="login" type="text" id="tfLogin" name="login" placeholder="Digite o login do novo administrador"/>
        <label for="tfSenha">Senha*: </label>
        <sf:input path="senha" type="password" id="tfSenha" name="senha" placeholder="Digitar senha de acesso"/>
        <label for="tfSenhaRepeat">Confirmação de senha*: </label>
        <input type="password" id="tfSenhaRepeat" name="senhaRepeat" placeholder="Redigitar senha de acesso"/>
    </c:otherwise>
</c:choose>

<label for="sfTipo">Autoridades*: </label>

<div id="autoridades">
    <sf:checkboxes items="${listaAutoridades}" delimiter="</br>" path="authorities" cssClass="box_autoridade"
                   itemValue="authority" itemLabel="descricao"></sf:checkboxes>
</div>

<sf:input type="hidden" path="foto" value="default"/>  
<sf:input type="hidden" path="tipo" value="default"/>  
<sf:input type="hidden" path="id"/>
<sf:input type="hidden" path="dataCadastro"/>

<br/>
<button type="submit" id="btEnviar" onclick="return false">Cadastrar</button>
<button type="reset" id="btLimpar">Limpar</button>    

So, I'm having a lot of hidden fields, in order to fill all the attributes of the Usuario object that I don't want to change. I could just omit all these hidden fields and retrieve the object from database in my controller, but I think it wouldn't be correct.

My question is: is the hidden field approach correct? If it's not, what's the most recommended way to update an object from a form?

Thank you.

Answer 1

I think, the best approach depends on what you need from your application. Security? - sending unnecessary data to the client may be a bad idea. Scalability? - your approach probably is the most scalable. Performance? - you may consider storing your usuario object in a session attribute between controller invocations instead of retrieving its data from the DB.

If you decide to store the Usuario form backing object as a session attribute between controller invocations, Spring MVC has the @SessionAttribute annotation. Here is an example of its usage.

Answer 2

Mostly when I have a form that doesn't exactly matches the persisted object I end up creating a new class which will represent that particular piece of data. You could also refactor your domain object into several classes which will individually match a form. The major benefit from this approach is that can easily validate each instance which would be difficult if you expect the full, in this case, User object with partial data when submitting the form.

This example is just for illustration. In general it's better to create separate tables/entities instead of one big table/entity.

@Entity
class User extends UserDetails {
    @Id
    private Long id;
}


@MappedSuperclass
class User extends UserDetails {
    @NotNull
    @NotBlank
    private String username;
    private String password;
}


@MappedSuperclass
class UserProfile {
    private String name;
    private String address;
    @Email
    private String email;
}