Question

我已查看其他问题this和this等，问题是我的转换被调用但selectOneMenu的值不会改变< / strong>即可。我的实体类是生成的，并且具有equals和hashCode，我不想更改其中的任何内容 - 如果它被重新生成，那么所有更改都将丢失（解决方法是更改实体类的String）。

XHTML代码剪断：

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

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()); } } }

实体类已剪切（生成此内容）：

... @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; }

当页面加载时，我可以看到日志语句如下：

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

因此转换器被调用并返回正确的值，但在页面上它仍然是 com.xyz.Def [defid = 1] （下拉和正常）

Answer 1

转换器似乎正在运行，但您没有发布整个<p:selectOneMenu>代码，特别是<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。

Answer 2

尝试以下代码

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

Converter用于在复杂的Java对象和String表示之间进行转换。为此，您需要将整个def对象指定为项目值。您还应确保＃{abcController.selected.def}引用def属性，而不是某些表示def ID的Long属性。

Primefaces selectOneMenu转换器调用但不工作

2 个答案: