Question

我正在尝试在glassfish-3.1.2下开发一个应用程序。我有以下群组实体：

@Entity
@NamedQueries({
@NamedQuery(name = Groups.FIND_BY_ID, query="SELECT g FROM Groups g WHERE g.id = :id"),
@NamedQuery(name = Groups.FIND_BY_NAME, query="SELECT g FROM Groups g WHERE g.group_name = :name"),
@NamedQuery(name = Groups.FIND_ALL, query="SELECT g FROM Groups g ORDER BY g.group_name")})

public class Groups implements Serializable {

    public static final String FIND_ALL = "Groups.findAll";
    public static final String FIND_BY_ID = "Groups.findById";
    public static final String FIND_BY_NAME = "Groups.findByName";

    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String group_name;
    private String group_desc;
    @ManyToMany(mappedBy = "UsersGroups")
    private List<Users> user;
    /* Follow setters and getters

和固件实体：

@Entity
@NamedQueries({
@NamedQuery(name = "findById", query="SELECT f FROM Firmware f WHERE f.id = :id"),
@NamedQuery(name = "findByType", query="SELECT f FROM Firmware f WHERE f.type = "type"),
@NamedQuery(name = "findAll", query="SELECT f FROM Firmware f ORDER BY f.type")})
public class Firmware implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String type; 
    /* Follow getters and setters */

以及以下豆类

@Stateless
@LocalBean  
public class GroupsEJB {
@PersistenceContext private EntityManager em;

 public Groups persist(Groups group) {
    em.persist(group);
    return group;
}

 public Groups getById(Long id) {
    TypedQuery<Groups> query = em.createNamedQuery("findById",   Groups.class).setParameter("id", id);
    return query.getSingleResult();
}

public List<Groups> getAllGroups() {
    TypedQuery<Groups> query = em.createNamedQuery("findAll", Groups.class);
    return query.getResultList();
}

public List<Groups> getByName(String name) {
    TypedQuery<Groups> query = em.createNamedQuery("findByName", Groups.class).setParameter("group_name", name);
    return query.getResultList();
}
}


@Stateless
@LocalBean                                                                          
public class FirmwareEJB {
@PersistenceContext private EntityManager em;
/**
 * Creates a new instance of FirmwareEJB
 */
public FirmwareEJB() {
}
  public Firmware persist(Firmware firmware) {
    em.persist(firmware);
    return firmware;
}

public List<Firmware> getAllFirmware() {
    TypedQuery<Firmware> query = em.createNamedQuery("findAll", Firmware.class);
    return query.getResultList();
}

public List<Firmware> getByType(String type) {
    TypedQuery<Firmware> query = em.createNamedQuery("findByType", Firmware.class).setParameter("type", type);
    return query.getResultList();
}
 public Firmware getById(Long id) {
    TypedQuery<Firmware> query = em.createNamedQuery("findById", Firmware.class).setParameter("id", id);
    return query.getSingleResult();
    //Firmware f = em.find(Firmware.class, id);
    //return f;
}        
}

以及以下控制器

@ManagedBean
@RequestScoped
public class GroupsController {

@EJB
private GroupsEJB groupsEJB;

private Groups group = new Groups();
private List<Groups> groupsList = new ArrayList<Groups>();


/**
 * Creates a new instance of GroupsController
 */
public GroupsController() {
}

public String createGroup() {
    return "createGroup.xhtml";
}

public String saveGroup() {

    group = groupsEJB.persist(group);
    groupsList = groupsEJB.getAllGroups();
    return "listGroups.xhtml";
}

public String listGroups() {
    groupsList = groupsEJB.getAllGroups();
    return "listGroups.xhtml";
}

public Groups getGroup() {
    return group;
}

public void setGroup(Groups group) {
    this.group = group;
}

public List<Groups> getGroupsList() {
    return groupsList;
}

public void setGroupsList(List<Groups> groupsList) {
    this.groupsList = groupsList;
}



@ManagedBean
@RequestScoped
public class FirmwareController {

@EJB
private FirmwareEJB firmwareEJB;
private Firmware firmware = new Firmware();
private List<Firmware> firmwareList = new ArrayList<Firmware>();

/**
 * Creates a new instance of FirmwareController
 */
public FirmwareController() {
}

public String newFirmware() {
    return "newFirmware.xhtml";
}

public String saveFirmware() {
    List type = firmwareEJB.getByType(firmware.getType());
    if (!type.isEmpty()) {
        addMessage("Firmware already exist.");
        return "newFirmware.xhtml";
    }
    firmware = firmwareEJB.persist(firmware);
    firmwareList = firmwareEJB.getAllFirmware();
    return "listFirmware.xhtml";
}

public String listFirmware() {
    firmwareList = firmwareEJB.getAllFirmware();
    return "listFirmware.xhtml";

}

public String searchFirmware() {
    return "searchFirmware.xhtml";
}

public String searchFirmwareById() {
    Long id = firmware.getId();
    Firmware f = firmwareEJB.getById(id);
    addMessage("Firmware: " + f.getType());
    return "searchFirmware.xhtml";
}

public List<Firmware> getFirmwareList() {
    return firmwareList;
}

public void setFirmwareList(List<Firmware> firmwareList) {
    this.firmwareList = firmwareList;
}

public Firmware getFirmware() {
    return firmware;
}

public void setFirmware(Firmware firmware) {
    this.firmware = firmware;
}

所以，当我使用以下jsf时：

 <ui:composition template="./base.xhtml">

        <ui:define name="content">
            <h:dataTable value="${groupsController.groupsList}" var="g" >

                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Group Name" />
                    </f:facet>
                    <h:outputText value="${g.group_name}" />
                </h:column>
                <h:column>
                    <f:facet name="header">
                        <h:outputText value="Group Description" />
                    </f:facet>
                    <h:outputText value="${g.group_desc}" />
                </h:column>

            </h:dataTable>
        </ui:define>

    </ui:composition>

显示组列表，我获取

javax.el.PropertyNotFoundException: /listGroups.xhtml @25,65 value="${g.group_name}": The class 'entities.Firmware' does not have the property 'group_name'.

我重建，重写，没有解决方案。我无法找到解决方案。任何人都可以帮助我吗？

Answer 1

要看到吸气剂和制定者会很好。只是在黑暗中拍摄：在属性中使用下划线不符合Java Bean cnovention。我相信这也可能是你问题的根源。我相信如果你摆弄套管，你可以解决它。我强烈建议您将该属性重命名为groupName并具有setGroupName和getGroupName，并使用g.groupName作为表达式。

奇怪的javax.el.propertynotfoundexception

1 个答案: