blocks|key|248885|text|您可以使用<f:selectItems+value="#{carBean.carList}"+/>并返回包装枚举的SelectItem实例列表(使用Status.values()获取所有可能的值)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|248886|entityMap^0|5|18|1L|A|22|F|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

You could use <code>&lt;f:selectItems value="#{carBean.carList}" /&gt;</code> and return a list of <code>SelectItem</code> instances that wrap the enum (use <code>Status.values()</code> to get all possible values).

blocks|key|245256|text|JSF有一个用于enum的内置转换器，因此应该这样做：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|245257|@Named
@ApplicationScoped
public+class+Data+{

++++public+Status[]+getStatuses()+{
++++++++return+Status.values();
++++}

}|code-block|syntax|javascript|245258|使用|245259|<h:selectOneMenu+value="#{bean.question.status}"+>
++++<f:selectItems+value="#{data.statuses}"+/>
</h:selectOneMenu>|245260|(注意:从JSF2.0开始，不再需要提供SelectItem[]或List<SelectItem>__，也接受T[]和List<T>，您可以通过var属性访问当前项)|245261|如果您碰巧使用JSF实用程序库OmniFaces，那么您可以使用而不是bean。|245262|<o:importConstants+type="com.example.Status"+/>

<h:selectOneMenu+value="#{bean.question.status}"+>
++++<f:selectItems+value="#{Status}"+/>
</h:selectOneMenu>|245263|如果您还想控制标签，可以将它们添加到Status枚举中：|245264|public+enum+Status+{

++++SUBMITTED("Submitted"),
++++REJECTED("Rejected"),
++++APPROVED("Approved");

++++private+String+label;

++++private+Status(String+label)+{
++++++++this.label+=+label;
++++}

++++public+String+getLabel()+{
++++++++return+label;
++++}

}|245265|245266|<f:selectItems+value="#{data.statuses}"+var="status"
++++itemValue="#{status}"+itemLabel="#{status.label}"+/>|245267|或者，更好的做法是将枚举值设置为本地化资源包的属性键(需要EL+3.0+)：|245268|<f:selectItems+value="#{data.statuses}"+var="status"
++++itemValue="#{status}"+itemLabel="#{text['data.status.'+%2B=+status]}"+/>|245269|在与资源束#{text}相关联的属性文件中|245270|data.status.SUBMITTED+=+Submitted
data.status.REJECTED+=+Rejected
data.status.APPROVED+=+Approved|245271|entityMap|0|LINK|mutability|MUTABLE|url|https://omnifaces.org/^0|8|4|0|0|0|0|K|C|X|G|1J|3|1N|7|20|3|0|F|9|0|0|0|I|6|0|0|0|0|0|0|5|7|0|0^^$0|@$1|2|3|4|5|6|7|1H|8|@$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1K|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1L|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1M|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1N|8|@$9|1O|A|1P|B|C]|$9|1Q|A|1R|B|C]|$9|1S|A|1T|B|C]|$9|1U|A|1V|B|C]|$9|1W|A|1X|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1Y|8|@]|D|@$9|1Z|A|20|1|21]]|E|$]]|$1|S|3|T|5|H|7|22|8|@]|D|@]|E|$I|J]]|$1|U|3|V|5|6|7|23|8|@$9|24|A|25|B|C]]|D|@]|E|$]]|$1|W|3|X|5|H|7|26|8|@]|D|@]|E|$I|J]]|$1|Y|3|L|5|6|7|27|8|@]|D|@]|E|$]]|$1|Z|3|10|5|H|7|28|8|@]|D|@]|E|$I|J]]|$1|11|3|12|5|6|7|29|8|@]|D|@]|E|$]]|$1|13|3|14|5|H|7|2A|8|@]|D|@]|E|$I|J]]|$1|15|3|16|5|6|7|2B|8|@$9|2C|A|2D|B|C]]|D|@]|E|$]]|$1|17|3|18|5|H|7|2E|8|@]|D|@]|E|$I|J]]|$1|19|3|-4|5|6|7|2F|8|@]|D|@]|E|$]]]|1A|$1B|$5|1C|1D|1E|E|$1F|1G]]]]

JSF has a builtin converter for <code>enum</code>, so this should do:
<pre class="lang-java prettyprint-override"><code>@Named
@ApplicationScoped
public class Data {

 public Status[] getStatuses() {
 return Status.values();
 }

}
</code></pre>
with
<pre class="lang-html prettyprint-override"><code>&lt;h:selectOneMenu value=&quot;#{bean.question.status}&quot; &gt;
 &lt;f:selectItems value=&quot;#{data.statuses}&quot; /&gt;
&lt;/h:selectOneMenu&gt;
</code></pre>
(note: since JSF 2.0 there's no need anymore to provide a <code>SelectItem[]</code> or <code>List&lt;SelectItem&gt;</code>, a <code>T[]</code> and <code>List&lt;T&gt;</code> are accepted as well and you can access the current item by <code>var</code> attribute)
If you happen to use JSF utility library <a href="https://omnifaces.org" rel="nofollow noreferrer">OmniFaces</a>, then you could use <a href="https://showcase.omnifaces.org/taghandlers/importConstants" rel="nofollow noreferrer"><code>&lt;o:importConstants&gt;</code></a> instead of a bean.
<pre class="lang-html prettyprint-override"><code>&lt;o:importConstants type=&quot;com.example.Status&quot; /&gt;

&lt;h:selectOneMenu value=&quot;#{bean.question.status}&quot; &gt;
 &lt;f:selectItems value=&quot;#{Status}&quot; /&gt;
&lt;/h:selectOneMenu&gt;
</code></pre>
If you intend to control the labels as well, you could add them to the <code>Status</code> enum:
<pre class="lang-java prettyprint-override"><code>public enum Status {

 SUBMITTED(&quot;Submitted&quot;),
 REJECTED(&quot;Rejected&quot;),
 APPROVED(&quot;Approved&quot;);

 private String label;

 private Status(String label) {
 this.label = label;
 }

 public String getLabel() {
 return label;
 }

}
</code></pre>
with
<pre class="lang-html prettyprint-override"><code>&lt;f:selectItems value=&quot;#{data.statuses}&quot; var=&quot;status&quot;
 itemValue=&quot;#{status}&quot; itemLabel=&quot;#{status.label}&quot; /&gt;
</code></pre>
Or, better, make the enum value a property key of a localized resource bundle (EL 3.0 required):
<pre class="lang-html prettyprint-override"><code>&lt;f:selectItems value=&quot;#{data.statuses}&quot; var=&quot;status&quot;
 itemValue=&quot;#{status}&quot; itemLabel=&quot;#{text['data.status.' += status]}&quot; /&gt;
</code></pre>
with this in a properties file associated with resource bundle <code>#{text}</code>
<pre class="lang-none prettyprint-override"><code>data.status.SUBMITTED = Submitted
data.status.REJECTED = Rejected
data.status.APPROVED = Approved
</code></pre>

blocks|key|250195|text|对于本地化，我们也可以使用这个解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|250196|public+enum+Status+{+SUBMITTED,+REJECTED,+APPROVED+}

data.status.SUBMITTED=Submitted
data.status.REJECTED=Rejected
data.status.APPROVED=Approved

<h:selectOneMenu+value="#{bean.question.status}"+>
++++<f:selectItems
++++++++value="#{data.statuses}"
++++++++var="status"
++++++++itemValue="#{status}"
++++++++itemLabel="#{text['data.status.'.concat(status)]}"+/>
</h:selectOneMenu>|code-block|syntax|javascript|250197|因此本地化字符串的资源路径不是硬编码在Enum中的。|250198|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

For localization we can use also this solution:

<pre><code>public enum Status { SUBMITTED, REJECTED, APPROVED }

data.status.SUBMITTED=Submitted
data.status.REJECTED=Rejected
data.status.APPROVED=Approved

&lt;h:selectOneMenu value="#{bean.question.status}" &gt;
 &lt;f:selectItems
 value="#{data.statuses}"
 var="status"
 itemValue="#{status}"
 itemLabel="#{text['data.status.'.concat(status)]}" /&gt;
&lt;/h:selectOneMenu&gt;
</code></pre>

So the resource path for localization strings are not hardcoded in Enum.

blocks|key|250209|text|例如，您可以使用以下实用工具el函数来获取枚举值并在SelectOneMenu中使用它们。不需要创建bean和样板方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|250210|public+final+class+ElEnumUtils
{
++++private+ElEnumUtils()+{+}

++++/**
+++++*+Cached+Enumerations,+key+equals+full+class+name+of+an+enum
+++++*/
++++private+final+static+Map<String,+Enum<?>[]>+ENTITY_ENUMS+=+new+HashMap<>();;

++++/**
+++++*+Retrieves+all+Enumerations+of+the+given+Enumeration+defined+by+the
+++++*+given+class+name.
+++++*
+++++*+@param+enumClassName+Class+name+of+the+given+Enum.
+++++*
+++++*+@return
+++++*
+++++*+@throws+ClassNotFoundException
+++++*/
++++@SuppressWarnings("unchecked")
++++public+static+Enum<?>[]+getEnumValues(final+String+enumClassName)+throws+ClassNotFoundException
++++{
++++++++//+check+if+already+cached+-+use+classname+as+key+for+performance+reason
++++++++if+(ElEnumUtils.ENTITY_ENUMS.containsKey(enumClassName))
++++++++++++return+ElEnumUtils.ENTITY_ENUMS.get(enumClassName);

++++++++final+Class<Enum<?>>+enumClass+=+(Class<Enum<?>>)+Class.forName(enumClassName);

++++++++final+Enum<?>[]+enumConstants+=+enumClass.getEnumConstants();

++++++++//+add+to+cache
++++++++ElEnumUtils.ENTITY_ENUMS.put(enumClassName,+enumConstants);

++++++++return+enumConstants;
++++}
}|code-block|syntax|javascript|250211|在taglib文件中将其注册为el函数：|250212|<function>
++++<description>Retrieves+all+Enumerations+of+the+given+Enumeration+defined+by+the+given+class+name.</description>
++++<function-name>getEnumValues</function-name>
++++<function-class>
++++++++package.ElEnumUtils
++++</function-class>
++++<function-signature>
++++++++java.lang.Enum[]+getEnumValues(java.lang.String)
++++</function-signature>
</function>|250213|最后，我们这样称呼它：|250214|<p:selectOneMenu+value="#{bean.type}">
++++<f:selectItems+value="#{el:getEnumValues('package.BeanType')}"+var="varEnum"+
++++++++itemLabel="#{el:getEnumLabel(varEnum)}"+itemValue="#{varEnum}"/>
</p:selectOneMenu>|250215|与BalusC答案类似，您应该使用带有本地化枚举标签的资源包，并且为了使代码更简洁，您还可以创建像getEnumLabel(enum)这样的函数|250216|entityMap^0|Q|D|0|0|0|0|0|0|1D|I|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@]|D|@]|E|$]]|$1|Q|3|R|5|H|7|13|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|V|$]]

You can use following utility el function to obtain the enum values and use them in a <code>SelectOneMenu</code> for example. No need to create beans and boilerplate methods.

<pre><code>public final class ElEnumUtils
{
 private ElEnumUtils() { }

 /**
 * Cached Enumerations, key equals full class name of an enum
 */
 private final static Map&lt;String, Enum&lt;?&gt;[]&gt; ENTITY_ENUMS = new HashMap&lt;&gt;();;

 /**
 * Retrieves all Enumerations of the given Enumeration defined by the
 * given class name.
 *
 * @param enumClassName Class name of the given Enum.
 *
 * @return
 *
 * @throws ClassNotFoundException
 */
 @SuppressWarnings("unchecked")
 public static Enum&lt;?&gt;[] getEnumValues(final String enumClassName) throws ClassNotFoundException
 {
 // check if already cached - use classname as key for performance reason
 if (ElEnumUtils.ENTITY_ENUMS.containsKey(enumClassName))
 return ElEnumUtils.ENTITY_ENUMS.get(enumClassName);

 final Class&lt;Enum&lt;?&gt;&gt; enumClass = (Class&lt;Enum&lt;?&gt;&gt;) Class.forName(enumClassName);

 final Enum&lt;?&gt;[] enumConstants = enumClass.getEnumConstants();

 // add to cache
 ElEnumUtils.ENTITY_ENUMS.put(enumClassName, enumConstants);

 return enumConstants;
 }
}
</code></pre>

Register it as an el function in a taglib file:

<pre><code>&lt;function&gt;
 &lt;description&gt;Retrieves all Enumerations of the given Enumeration defined by the given class name.&lt;/description&gt;
 &lt;function-name&gt;getEnumValues&lt;/function-name&gt;
 &lt;function-class&gt;
 package.ElEnumUtils
 &lt;/function-class&gt;
 &lt;function-signature&gt;
 java.lang.Enum[] getEnumValues(java.lang.String)
 &lt;/function-signature&gt;
&lt;/function&gt;
</code></pre>

And finally call it like:

<pre><code>&lt;p:selectOneMenu value="#{bean.type}"&gt;
 &lt;f:selectItems value="#{el:getEnumValues('package.BeanType')}" var="varEnum" 
 itemLabel="#{el:getEnumLabel(varEnum)}" itemValue="#{varEnum}"/&gt;
&lt;/p:selectOneMenu&gt;
</code></pre>

Similiar to BalusC answer you should be using a resource bundle with localized enum labels and for cleaner code you can also create a function like <code>getEnumLabel(enum)</code>

I want to make a selectOneMenu dropdown so I can select a status on my question. Is it possible to make the f:selectItem more flexible considering what happens if the order of the enums changes, and if the list was large? And could I do this better? And is it possible to automatically "select" the item that the question have?

Enum class

<pre><code>public enum Status {
 SUBMITTED,
 REJECTED,
 APPROVED
}
</code></pre>

Question entity

<pre><code>@Enumerated(EnumType.STRING)
private Status status;
</code></pre>

JSF

<pre><code>&lt;div class="field"&gt;
 &lt;h:outputLabel for="questionStatus" value="Status" /&gt;
 &lt;h:selectOneMenu id="questionStatus" value="#{bean.question.status}" &gt;
 &lt;f:selectItem itemLabel="Submitted" itemValue="0" /&gt;
 &lt;f:selectItem itemLabel="Rejected" itemValue="1" /&gt;
 &lt;f:selectItem itemLabel="Approved" itemValue="2" /&gt;
 &lt;/h:selectOneMenu&gt;
 &lt;hr /&gt;
&lt;/div&gt;
</code></pre>

How to use enum values in f:selectItem(s)

我想创建一个selectOneMenu下拉列表，这样我就可以选择我的问题的状态。有没有可能让f:selectItem更灵活，考虑到如果枚举的顺序改变了会发生什么，如果列表很大会发生什么？我能做得更好吗？是否有可能自动“选择”问题所具有的项目？枚举类public enum Status {    SUBMITTED,  ...

问如何在f:selectItem(s)中使用枚举值
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