提交带有选择字段的表单时出错

Question

在我目前的spring项目中,我的表单实现了这样的结构:

<form class="form" id="Pagina" role="form" method="POST" action="/loja/Pagina/cadastra" enctype="multipart/form-data">
...
</form>

并且它在服务器中由此方法处理:

调节器

@RequestMapping(value="cadastra", method=RequestMethod.POST)
@ResponseBody
@ResponseStatus(HttpStatus.CREATED)
public E cadastra(@ModelAttribute("object") E object, BindingResult result, @RequestParam(value="file", required=false) MultipartFile file, @RequestParam(value="icone", required=false) MultipartFile icone, @RequestParam(value="screenshot", required=false) MultipartFile screenshot[]) throws Exception {
    E ret = serv.cadastra(object, file, icone, screenshot);
    if (ret != null)
        return ret;
    else
        throw new Exception();
}

服务

@PreAuthorize("hasPermission(#user, 'cadastra_'+#this.this.name)")
@Transactional
public E cadastra(E e, MultipartFile file, MultipartFile icone, MultipartFile[] screenshot) {
    return dao.persist(e);
}

我的问题是当表单有这样的字段时:

<label>pagina</label>
<select name="pagina.id" class="form-control select" data-lista="/loja/Pagina/listagem.json">
...
</select>

<label>produto</label>
<select name="produto.id" class="form-control select" data-lista="/loja/Produto/listagem.json">
...
</select>

在entiy类中映射这样的属性:

@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name="pagina_mae", nullable = true)
@Order(value=5)
@Select(name="pagina", ordem = 5)
@Sidebar
private Pagina pagina;

@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name="produto_mae", nullable = true)
@Order(value=6)
@Select(name="produto", ordem = 6)
@Sidebar
private Produto produto;

里面的选项看起来像这样:

<option value="">.</option>
<option value="...">...</option>

如果我提交选择了空白选项的表单,我会收到此错误:

object references an unsaved transient instance - save the transient instance before flushing: com.spring.loja.model.pagina.persistence.model.Pagina; nested exception is org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.spring.loja.model.pagina.persistence.model.Pagina

但是,例如,如果在数据库中手动插入记录(在我的情况下,使用pgAdmin3),并在select中选择此项,则表单将无错误地提交.

任何人都可以告诉我如何解决这个问题,允许我提交包含或不包含选定数据的表单<select>.

UPDATE

该类的代码Pagina:

@Entity
@Table(name="pagina")
@MainForm(grupo = 2, icone = "file")
public class Pagina extends ModelEntity {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;

    @Column(name = "nome", unique = true)
    @Order(value=1)
    @Input(type="hidden", name="nome", ordem = 1)
    private String nome;

    @Column(name = "titulo", nullable = false)
    @Order(value=2)
    @Input(name="titulo", ordem = 2)
    private String titulo;

    @Column(name = "descricao", length=65535)
    @Order(value=4)
    @Textarea(name="descricao", ordem = 4)
    private String descricao;

    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name="pagina_mae", nullable = true)
    @Order(value=5)
    @Select(name="pagina", ordem = 5)
    @Sidebar
    private Pagina pagina;

    @OneToOne(fetch = FetchType.EAGER)
    @JoinColumn(name="produto_mae", nullable = true)
    @Order(value=6)
    @Select(name="produto", ordem = 6)
    @Sidebar
    private Produto produto;
}

更新2

PaginaEditor.java

@Component
public class PaginaEditor extends PropertyEditorSupport {

    @Inject
    private PaginaService paginaService;

    @Override
    public void setAsText(String text) {
        if (!text.isEmpty()) {
            Pagina pagina = paginaService.getObject(text);
            setValue(pagina);
        }
    }

}

方法添加到我的控制器:

@InitBinder
public void initBinder(WebDataBinder binder) {
    binder.registerCustomEditor(Pagina.class, new PaginaEditor());
}

Answer 1

在Spring MVC中选择是棘手的.

我认为你的问题是,当你的主要实体进入要保持的数据层时,关系就不存在了.

尝试调试并检查上面的确认是否属实.

有两种方法可以对此进行排序.

让我们假设一个联系人系统中的公司/联系人关系.公司有很多联系人,联系人有一家公司.

公司片段.

// package declaration imports and all
@Entity
@Table(name = "company")
public class Company {

    private String name;

    @OneToMany(mappedBy = "company")
    private List<Contact> contacts = new ArrayList<Contact>();

    // getter and setters and any extra stuff you fancy putting here

}

联系代码段

// package declaration imports and all
@Entity
@Table(name = "contact")
public class Contact {

    private String name;

    @ManyToOne
    private Company company;

    // getter and setters and any extra stuff you fancy putting here

}

和一个带选择的jsp片段.我们假设模型中存在"联系"对象和客户列表.

<form:form modelAttribute="contact">
    <form:input path="name" />
    <form:select path="customer" items="${customers}" itemValue="id" itemLabel="name" />
</form:form>

使用此代码,您可以使用像这样的PropertyEditor.

@Component
public class CustomerEditor extends PropertyEditorSupport {

    @Inject
    private CustomerService customerService;

    @Override
    public void setAsText(String text) {
        if (StringUtils.isNotBlank(text)) {
            Customer customer = this.customerService.findById(Integer
                    .valueOf(text));
            this.setValue(customer);
        }
    }

}

并在你的Spring Context中注册.

@InitBinder
public void initBinder(WebDataBinder binder) {
    binder.registerCustomEditor(Customer.class, this.customerEditor);
}

这里发生的是,每当Spring找到一个Customer类型的Object时,它将使用PropertyEditor将(在这种情况下)Id转换为对象,并通过类型将联系人(在本例中)转换为数据层(Hibernate) ),适当的客户实体将在那里等待拉里的快乐.

这是一种自动化的方式.

另一种方法是创建表单/ DTO或您想要调用的任何内容,并添加包含customerId字段的字段(在本例中)并在保存实体之前转换您的自身.

我希望我能理解你的问题,因为我花了几分钟写这个... :)