Primefaces selectOneMenu转换器已调用但不起作用 [英] Primefaces selectOneMenu converter called but not working

问题描述

我查看了此和

转换器:

@FacesConverter("defConverter")
public class DefConverter implements Converter
{
    private static final Logger LOG = Logger.getLogger(DefConverter.class.getName());
    @EJB
    private DefFacade defFacade;

    @Override
    public Object getAsObject(FacesContext fc, UIComponent uic, String string)
    {
        LOG.info("getAsObject: " + string);
        try
        {
            return defFacade.findWithNFieldsWithValue("name", string, "=").get(0);
        }
        catch (Exception ex)
        {
            LOG.log(Level.SEVERE, "Error while fetching Def for " + string, ex);
        }
        return null;
    }

    @Override
    public String getAsString(FacesContext fc, UIComponent uic, Object obj)
    {
        LOG.info("getAsString obj class: " + obj.getClass().getName());
        if(obj instanceof Def)
        {
            Def def = (Def)obj;
            LOG.info("getAsString def name: " + def.getName());
            return def.getName();
        }
        else
        {
            StringBuilder sbError = new StringBuilder("The object of class ");
            sbError.append(obj.getClass().getName()).append(" is not of Def");
            throw new ClassCastException(sbError.toString());
        }
    }
}

实体类被剪断(生成):

...
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "defid")
private Long defid;
...

@Override
public int hashCode()
{
    int hash = 0;
    hash += (defid != null ? defid.hashCode() : 0);
    return hash;
}

@Override
public boolean equals(Object object)
{
    // TODO: Warning - this method won't work in the case the id fields are not set
    if (!(object instanceof Def))
    {
        return false;
    }
    Def other = (Def) object;
    if ((this.defid == null && other.defid != null) || (this.defid != null && !this.defid.equals(other.defid)))
    {
        return false;
    }
    return true;
}

页面加载后，我可以看到以下日志语句:

getAsString obj class: com.xyz.Def
getAsString def name: Name 1
getAsString obj class: com.xyz.Def
getAsString def name: Name 2
getAsString obj class: com.xyz.Def
getAsString def name: Name 3

因此将调用转换器并返回正确的值，但是在页面上它仍然是 com.xyz.Def [defid = 1] (下拉并正常显示)

解决方案

转换器似乎正在运行，但是您并未发布整个<p:selectOneMenu>代码，尤其是<f:selectItems>.它应该看起来像这样

<p:selectOneMenu id="defid" 
                 value="#{abcController.selected.defid}"
                 converter="defConverter">
    <f:selectItems value="#{abcController.defs}" var="def"
                       itemLabel="#{def.name}" itemValue="#{def.defId}" />
</p:selectOneMenu>

itemLabel负责打印显示的值.

I've looked at the other questions this and this, etc, the problem is that my convert gets called but the values of selectOneMenu doesn't change. My entity class is generated, and has equals as well as hashCode and I would like not to change anything in it - if it gets regenerated then all changes will be lost (The work around is to change toString of the entity class).

The XHTML code snipped:

<p:selectOneMenu id="defid" 
                 value="#{abcController.selected.defid}"
                 converter="defConverter">

The Converter:

@FacesConverter("defConverter")
public class DefConverter implements Converter
{
    private static final Logger LOG = Logger.getLogger(DefConverter.class.getName());
    @EJB
    private DefFacade defFacade;

    @Override
    public Object getAsObject(FacesContext fc, UIComponent uic, String string)
    {
        LOG.info("getAsObject: " + string);
        try
        {
            return defFacade.findWithNFieldsWithValue("name", string, "=").get(0);
        }
        catch (Exception ex)
        {
            LOG.log(Level.SEVERE, "Error while fetching Def for " + string, ex);
        }
        return null;
    }

    @Override
    public String getAsString(FacesContext fc, UIComponent uic, Object obj)
    {
        LOG.info("getAsString obj class: " + obj.getClass().getName());
        if(obj instanceof Def)
        {
            Def def = (Def)obj;
            LOG.info("getAsString def name: " + def.getName());
            return def.getName();
        }
        else
        {
            StringBuilder sbError = new StringBuilder("The object of class ");
            sbError.append(obj.getClass().getName()).append(" is not of Def");
            throw new ClassCastException(sbError.toString());
        }
    }
}

The entity class snipped (this is generated):

...
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "defid")
private Long defid;
...

@Override
public int hashCode()
{
    int hash = 0;
    hash += (defid != null ? defid.hashCode() : 0);
    return hash;
}

@Override
public boolean equals(Object object)
{
    // TODO: Warning - this method won't work in the case the id fields are not set
    if (!(object instanceof Def))
    {
        return false;
    }
    Def other = (Def) object;
    if ((this.defid == null && other.defid != null) || (this.defid != null && !this.defid.equals(other.defid)))
    {
        return false;
    }
    return true;
}

When the page loads, I can see the log statements as follow:

getAsString obj class: com.xyz.Def
getAsString def name: Name 1
getAsString obj class: com.xyz.Def
getAsString def name: Name 2
getAsString obj class: com.xyz.Def
getAsString def name: Name 3

Thus the converter gets called and returns the correct values but on the page it is still com.xyz.Def[ defid=1 ] (Drop down and normal)

解决方案

The converter seems to be working, but you didn't post the whole <p:selectOneMenu> code, in particular <f:selectItems>. It should look something like this

<p:selectOneMenu id="defid" 
                 value="#{abcController.selected.defid}"
                 converter="defConverter">
    <f:selectItems value="#{abcController.defs}" var="def"
                       itemLabel="#{def.name}" itemValue="#{def.defId}" />
</p:selectOneMenu>

itemLabel is responsible for printing displayed values.

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