Spring form:select multiple selected value? - spring

Question

I have this edit form:
I want that the roles of the user get selected. If this were one-to-many relation I know that I can do something like this:
<form:label path="roles">Roles:</form:label>
<form:select multiple="true" path="roles">
<c:forEach items="${roles}" var="rol">
<c:choose>
<c:when
test="${usuarioEdit.rol.id ==rol.id}">
<option value="${rol.id}" selected="selected">${rol.nombre}</option>
</c:when>
<c:otherwise>
<option value="${rol.id}">${rol.nombre}</option>
</c:otherwise>
</c:choose>
</c:forEach>
</form:select>
<form:errors cssStyle="color:red" path="roles"></form:errors>
But this is a many-to-many relation. How can I get selected the options in an edit form?. Is there an easy form?
This code works, but I wonder if spring gives any facilities:
<form:select multiple="true" path="roles">
<c:forEach items="${roles}" var="rol">
<c:set var="isSelected" value="false" />
<c:forEach items="${rolesUsu}" var="rolUsu">
<c:if test="${rolUsu.getRol().getId()==rol.id}">
<c:set var="isSelected" value="true" />
</c:if>
</c:forEach>
<c:choose>
<c:when test="${isSelected}">
<option value="${rol.id}" selected="selected">${rol.nombre}</option>
</c:when>
<c:otherwise>
<option value="${rol.id}">${rol.nombre}</option>
</c:otherwise>
</c:choose>
</c:forEach>
</form:select>
Edit:
In my controller I have:
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(Set.class, "roles",
new RolCollectionEditor(Set.class, rolDao));
}
RolCollectionEditor:
public class RolCollectionEditor extends CustomCollectionEditor {
private final RolDAO rolDao;
public RolCollectionEditor(Class<?> collectionType, RolDAO rolDao) {
super(collectionType);
this.rolDao = rolDao;
}
#Override
protected Object convertElement(Object element) {
String rolId = (String) element;
Rol rol = rolDao.findById(rolId);
Usuario_Rol usuRol = new Usuario_Rol();
//Agregamos un usuario vacio temporal
//y lo sobreescribimos en el controlador
Usuario usuario = new Usuario();
usuRol.setUsuario(usuario);
usuRol.setRol(rol);
usuRol.setFechaCreacion(new Date());
usuRol.setFechaModificacion(new Date());
usuRol.setStatus("activo");
return usuRol;
}
}
Here Usuario_Rol is an intermediate table for the many to many relation, that have other attributes besides the userId and rolId.
Edit2:
Rol class:
#Entity
#Table(name = "rol", uniqueConstraints = { #UniqueConstraint(columnNames = "nombre") })
public class Rol implements Serializable{
#Id
#Column(name = "_id")
private String id;
#Column(name = "nombre")
#NotNull
private String nombre;
#Column(name = "descripcion")
private String descripcion;
#Column(name = "status")
private String status;
#Column(name = "fechaCreacion")
private Date fechaCreacion;
#Column(name = "fechaModificacion")
private Date fechaModificacion;
#Column(name = "fechaSincronizacion")
private Date fechaSincronizacion;
#OneToMany(fetch = FetchType.EAGER, mappedBy = "usuarioRol_pk.rol", orphanRemoval = true, cascade=CascadeType.ALL)
private Set<Usuario_Rol> usuarios = new HashSet<Usuario_Rol>(0);
//getters and setters
#Override
final public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((nombre == null) ? 0 : nombre.hashCode());
return result;
}
#Override
final public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Rol))
return false;
Rol other = (Rol) obj;
if (nombre == null) {
if (other.nombre != null)
return false;
} else if (!nombre.equals(other.nombre))
return false;
return true;
}
Class Usuario:
#Entity
#Table(name = "usuario", uniqueConstraints = {
#UniqueConstraint(columnNames = "login"),
#UniqueConstraint(columnNames = "correo") })
public class Usuario implements Serializable {
#Id
#Column(name = "_id")
private String id;
#Column(name = "nombre")
#NotEmpty
private String nombre;
#Column(name = "apellido")
#NotEmpty
private String apellido;
#Column(name = "login")
#Size(min = 4)
#NotEmpty
private String login;
#Column(name = "password")
#NotEmpty
#Size(min = 4)
private String password;
#Column(name = "salt")
private String salt;
#Column(name = "correo")
#NotEmpty
#Email
private String correo;
#Column(name = "token")
private String token;
#Column(name = "status")
private String status;
#Column(name = "fechaUltimoLogin")
private Date fechaUltimoLogin;
#Column(name = "fechaCreacion")
private Date fechaCreacion;
#Column(name = "fechaModificacion")
private Date fechaModificacion;
#Column(name = "fechaSincronizacion")
private Date fechaSincronizacion;
#NotEmpty
#OneToMany(fetch = FetchType.EAGER, mappedBy = "usuarioRol_pk.usuario", orphanRemoval = true, cascade = CascadeType.ALL)
private Set<Usuario_Rol> roles = new HashSet<Usuario_Rol>(0);
//constructor, getters and setters.
#Override
final public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((login == null) ? 0 : login.hashCode());
return result;
}
#Override
final public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Usuario))
return false;
Usuario other = (Usuario) obj;
if (login == null) {
if (other.login != null)
return false;
} else if (!login.equals(other.login))
return false;
return true;
}
Intermediate class:
#Entity
#Table(name = "usuario_rol")
#AssociationOverrides({
#AssociationOverride(name = "usuarioRol_pk.usuario", joinColumns = #JoinColumn(name = "idUsuario")),
#AssociationOverride(name = "usuarioRol_pk.rol", joinColumns = #JoinColumn(name = "idRol"))
})
public class Usuario_Rol implements Serializable{
#EmbeddedId
private Usuario_RolId usuarioRol_pk = new Usuario_RolId();
#Temporal(TemporalType.DATE)
#Column(name = "fechaCreacion")
private Date fechaCreacion;
#Temporal(TemporalType.DATE)
#Column(name = "fechaModificacion")
private Date fechaModificacion;
#Temporal(TemporalType.DATE)
#Column(name = "fechaSincronizacion")
private Date fechaSincronizacion;
#Column(name = "status")
private String status;
//gettters, setters
#Override
final public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((usuarioRol_pk == null) ? 0 : usuarioRol_pk.hashCode());
return result;
}
#Override
final public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Usuario_Rol))
return false;
Usuario_Rol other = (Usuario_Rol) obj;
if (usuarioRol_pk == null) {
if (other.usuarioRol_pk != null)
return false;
} else if (!usuarioRol_pk.equals(other.usuarioRol_pk))
return false;
return true;
}
Usuario_RolId:
#Embeddable
public class Usuario_RolId implements Serializable{
#ManyToOne
private Usuario usuario;
#ManyToOne
private Rol rol;
public Usuario getUsuario() {
return usuario;
}
public void setUsuario(Usuario usuario) {
this.usuario = usuario;
}
public Rol getRol() {
return rol;
}
public void setRol(Rol rol) {
this.rol = rol;
}
#Override
final public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((rol == null) ? 0 : rol.hashCode());
result = prime * result + ((usuario == null) ? 0 : usuario.hashCode());
return result;
}
#Override
final public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (!(obj instanceof Usuario_RolId))
return false;
Usuario_RolId other = (Usuario_RolId) obj;
if (rol == null) {
if (other.rol != null)
return false;
} else if (!rol.equals(other.rol))
return false;
if (usuario == null) {
if (other.usuario != null)
return false;
} else if (!usuario.equals(other.usuario))
return false;
return true;
}
This last class is used for the trick of simulating a many to many relation. I have followed this tutorial: http://www.mkyong.com/hibernate/hibernate-many-to-many-example-join-table-extra-column-annotation/

Answer 1

Why are you writing your own? Spring should be able to do that for you. Instead of a <c:forEach /> replace that whole block with a <form options .. /> tags. Spring will then be able to do the selection itself (you might need a Converter or PropertyEditor for that).
<form:select multiple="true" path="roles" items="${roles}" itemLabel="nombre" itemValue="id" />
Something along these lines...
Links:
Form Options documentation
Form Select documentation
Reference Guide

Answer 2

If you use this:
<form:select multiple="true" path="roles" items="${roles}" itemLabel="nombre" itemValue="id" />
you need to override toString() method of Usuario_Rol, in the right way for your class, to ensure that Spring pre-selects the initial values for you.

Answer 3

If I understand the question correctly, what you want is your Spring tag to generate HTML like this one:
<select id="roles" name="roles multiple="multiple">
<option value="1">Administrador</option>
<option value="2">Usuario avanzado</option>
<option value="3" selected="selected">Usuario </option>
<option value="4" selected="selected">Invitado</option>
</select>
As you can see, two values are selected ("Usuario" and "Invitado").
The "roles" model attribute that "path" refers to in your Spring tag has be an array instead of a single value. It's as easy as that. Please be aware that I set the array by hand in my controller. I am not familiar with the implications on the ORM side of your code.

Answer 4

I think you want to expect output like this:
<select id="roles" name="roles" multiple="multiple">
<option value="1">Administrador</option>
<option value="2" selected="selected">Usuario avanzado</option>
<option value="3" selected="selected">Usuario </option>
</select>
In model class you can create method for "roles" which should return array. Add your business complexity in that method.
public Integer[] getRoles(){
Integer[] selectedRoles = {2,3};
return selectedRoles;
}
In JSP:
<form:select multiple="true" path="roles">
<form:options items="${...}" itemValue="..." itemLabel="..."/>
</form>