entityMap|0|type|LINK|mutability|MUTABLE|data|url|http://blog.primefaces.org/?p=1867|blocks|key|e6u97|text|通过进程(在JSF规范中称为execute)，您告诉JSF将处理限制到指定的组件，其他所有内容都被忽略。|unstyled|depth|inlineStyleRanges|entityRanges|62vt7|update指示当服务器响应您的请求时将更新哪个元素。|19d1s|@all：每个组件都被处理/渲染。|fi8uf|@this：处理/呈现具有execute属性的请求组件。|5d7ij|@form：处理/呈现包含请求组件的表单。|8p1v8|@parent：处理/呈现包含请求组件的父组件。|jula|有了Primefaces，你甚至可以使用JQuery选择器，看看这个博客：http://blog.primefaces.org/?p=1867|offset|length^0|0|0|0|0|0|0|11|Y|0^^$0|$1|$2|3|4|5|6|$7|8]]]|9|@$A|B|C|D|2|E|F|W|G|@]|H|@]|6|$]]|$A|I|C|J|2|E|F|X|G|@]|H|@]|6|$]]|$A|K|C|L|2|E|F|Y|G|@]|H|@]|6|$]]|$A|M|C|N|2|E|F|Z|G|@]|H|@]|6|$]]|$A|O|C|P|2|E|F|10|G|@]|H|@]|6|$]]|$A|Q|C|R|2|E|F|11|G|@]|H|@]|6|$]]|$A|S|C|T|2|E|F|12|G|@]|H|@$U|13|V|14|A|15]]|6|$]]]]

By process (in the JSF specification it's called execute) you tell JSF to limit the processing to component that are specified every thing else is just ignored. 

update indicates which element will be updated when the server respond back to you request.

@all : Every component is processed/rendered.

@this: The requesting component with the execute attribute is processed/rendered.

@form : The form that contains the requesting component is processed/rendered.

@parent: The parent that contains the requesting component is processed/rendered.

With Primefaces you can even use JQuery selectors, check out this blog: <a href="http://blog.primefaces.org/?p=1867" rel="noreferrer">http://blog.primefaces.org/?p=1867</a>

entityMap|0|type|LINK|mutability|MUTABLE|data|url|http://docs.oracle.com/javaee/7/api/javax/faces/component/UIComponent.html|1|http://docs.oracle.com/javaee/7/api/javax/faces/component/EditableValueHolder.html|2|http://docs.oracle.com/javaee/7/api/javax/faces/component/ActionSource.html|3|http://docs.oracle.com/javaee/7/api/javax/faces/event/ActionEvent.html|4|http://docs.oracle.com/javaee/7/api/javax/faces/component/UIForm.html|5|https://stackoverflow.com/questions/20080861/how-do-primefaces-selectors-as-in-update-myclass-work|6|https://stackoverflow.com/questions/14790014|7|8|9|https://stackoverflow.com/questions/10449862/what-is-the-correct-way-to-deal-with-jsf-2-0-exceptions-for-ajaxified-components/|10|https://stackoverflow.com/questions/8634156|11|https://stackoverflow.com/questions/20146630|12|https://stackoverflow.com/questions/30934671|13|https://stackoverflow.com/questions/28236228|14|https://stackoverflow.com/questions/7371903|blocks|key|1jiis|text|The+process属性是服务器端的，并且只能影响UIComponentS实现EditableValueHolder(输入字段)或ActionSource(命令字段)。The+process属性使用以空格分隔的客户机ID列表告诉JSF，在(部分)表单提交时必须在整个JSF生命周期中处理哪些组件。|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|UNDERLINE|entityRanges|8jnv0|然后，JSF将应用请求值(根据组件自己的客户端ID查找HTTP请求参数，然后在以下情况下将其设置为提交值EditableValueHolder组件或对新的ActionEvent在以下情况下ActionSource组件)，执行转换、验证和更新模型值(EditableValueHolder组件)，并最终调用排队的ActionEvent(ActionSource仅限组件)。JSF将跳过对未包含的所有其他组件的处理process属性。此外，还包括以下组件：rendered属性的计算结果为false在应用请求值期间，也将跳过阶段，作为防止篡改请求的保护措施的一部分。|3m1mp|请注意，它是在以下情况下使用的ActionSource组件(如)非常重要的一点是，还应将组件本身包含在process属性，特别是当您打算调用与组件关联的操作时。因此，下面的示例打算在调用某个命令组件时仅处理特定的输入组件，它将不起作用：|f137p|它将只处理#{bean.foo}和注释the+#{bean.action}。您还需要包括命令组件本身：|7l66l|或者，正如您显然发现的，使用@parent如果它们恰好是唯一具有共同父项的组件：|3j6ib|或者，如果它们都恰好是父元素的唯一组件UIForm组件，则还可以使用@form|5ukci|如果表单包含更多您希望在处理过程中跳过的输入组件，这有时是不可取的，当您希望基于ajax侦听器方法中的当前输入组件更新另一个输入组件或某些UI部分时，这种情况更常见。也就是说，您不希望其他输入组件上的验证错误妨碍ajax侦听器方法的执行。|65cer|然后是@all。这在process属性，但仅限于update属性。Aprocess="@all"的行为与process="@form"。HTML不支持一次提交多个表单。|e430|顺便说一句，还有一个@none这在您绝对不需要处理任何东西的情况下可能很有用，但是仅限我想通过以下方式更新一些特定的部件update，特别是那些内容不依赖于提交的值或操作侦听器的部分。|1ggu9|需要注意的是，process属性具有没有对HTTP请求负载(请求参数数量)的影响。这意味着，默认的发送包含在HTML表示中的“一切”的HTML行为将不会受到影响。如果您有一个很大的表单，并且想要将HTTP请求有效负载减少到处理过程中绝对需要的负载，即只包含process属性，则可以将partialSubmit属性在PrimeFaces+Ajax组件中，如或。你也可以通过编辑来进行全局配置web.xml并添加|d1pjc|primefaces.SUBMIT
++++partial|code-block|syntax|javascript|lv6l|或者，您也可以使用默认情况下使用此行为的OmniFaces+3.0%2B。|f1tlm|标准JSF等效于特定于PrimeFaces的process是execute从。它的行为完全相同，只是它不支持逗号分隔的字符串，而PrimeFaces支持(尽管我个人建议只坚持空格分隔的约定)，也不支持@parent关键字。此外，知道它的缺省值可能会很有用@formwhile，缺省为@this。最后，知道这一点也很有用process支持所谓的"PrimeFaces选择器“，另请参阅update=“@（.myClass）”中的PrimeFaces选择器如何工作？|b77l5|The+update属性是客户端的，并且可以影响所有UIComponents.update属性使用一个空格分隔的客户机in列表告诉JavaScript+(负责处理ajax请求/响应的那个)，HTML+DOM树中的哪些部分需要更新以响应表单提交。|9v4aa|然后，JSF将为此准备正确的ajax响应，其中包含仅限要更新的请求部件。JSF将跳过未涵盖的所有其他组件update属性，从而保持响应有效负载较小。此外，还包括以下组件：rendered属性的计算结果为false将跳过渲染响应阶段。请注意，即使它会返回true，则JavaScript无法在HTML+DOM树中更新它false。您需要包装它或更新它的父级。另请参阅Ajax更新/渲染在具有渲染属性的组件上不起作用。|opeq|通常，你会想要更新仅限这些组件真的吗需要在(部分)表单提交时在客户端“刷新”。下面的示例通过@form|9364s|(请注意process属性被省略，因为它缺省为@form已经)|2evke|虽然这可能会很好地工作，但在这个特定的例子中，输入和命令组件的更新是不必要的。除非您更改模型值foo和bar内部action方法(这反过来在UX透视图中是不直观的)，那么更新它们就没有意义了。消息组件是唯一真的吗需要更新：|4g295|然而，当你有很多这样的东西时，这就变得单调乏味了。这就是PrimeFaces选择器存在的原因之一。这些消息组件在生成的HTML输出中有一个通用的样式类ui-message，因此也应该执行以下操作：|ekmuh|(请注意，您应该将ID保留在消息组件上，否则@(...)没用的！同样，请参阅|bmb6t|update=“@（.myClass）”中的PrimeFaces选择器如何工作有关详细信息，请参见)|41msd|The+@parent仅更新父组件，从而覆盖当前组件和所有同级及其子项。如果您将表单分成不同的组，每个组都有自己的职责，这会更有用。The+@this显然，只更新当前组件。通常，只有当您需要在action方法中更改组件自己的HTML属性之一时，才需要这样做。例如。|fa650|想象一下oncomplete需要使用value中更改的action，那么如果组件没有更新，那么这个构造就不会工作，原因很简单oncomplete是生成的HTML输出的一部分(因此，在render响应期间会计算其中的所有EL表达式)。|ck34j|The+@all更新整个文档，请谨慎使用。通常，您希望为此使用真正的GET请求，而不是通过普通链接(+or+]或通过?faces-redirect=true或ExternalContext#redirect()进行POST后重定向。在效果上，表单process=“@update=”@ajax“@ajax”与非ajax(非部分)提交具有完全相同的效果。在我的整个JSF职业生涯中，我遇到的唯一合理的@all用例是在ajax请求期间出现异常的情况下完整地显示错误页面。另请参阅处理AJAXified+components?的JSF2.0异常的正确方法是什么|bhd0h|标准JSF等效于特定于PrimeFaces的update是render从。它的行为完全相同，只是它不支持逗号分隔的字符串，而PrimeFaces支持(尽管我个人建议只坚持空格分隔的约定)，也不支持@parent关键字。两者都有update和render默认为@none(即"nothing")。|3bkmt|另请参阅：|b3jod|如何查找ajax+update/render组件的客户端ID？找不到从"bar"|unordered-list-item|bfajn|引用了表达式"foo“的组件按PrimeFaces+p:commandButton时事件的执行顺序|9c6sm|如何在例如p:dataTable分页期间减少p:ajax的请求负载|ebqe|如何在p:对话框中显示p:dataTable中当前行的详细信息，并在保存后更新|3n3jo|如何在JSF页面中使用？单一形式？多种形式？嵌套表单？|ak4ov|atomic|52md5^0|4|7|Q|B|14|J|1U|C|2H|7|Q|B|14|J|1U|C|Q|B|0|14|J|1|1U|C|2|0|1G|J|25|B|2M|C|3G|J|4B|B|4N|C|5P|7|6A|8|6Q|5|25|B|25|B|3|0|F|C|1F|7|0|5|B|N|E|0|E|7|0|J|6|J|6|Y|5|J|6|4|0|0|3|4|A|7|O|6|Y|E|1G|F|0|A|5|1O|6|0|7|7|3K|7|3Y|D|5F|7|0|0|0|M|7|U|7|2S|7|3J|5|3X|5|4F|7|5B|14|5|0|4|6|Q|B|13|6|0|1G|6|2D|8|2T|5|3I|4|4E|5|52|P|6|0|1A|5|0|4|7|N|5|0|1B|3|1F|3|1K|6|0|23|A|0|M|6|0|0|13|7|0|4|7|1Y|5|0|4|A|I|5|R|6|1Q|A|0|4|4|1M|K|27|Q|3F|U|5J|4|1E|57|8|6L|N|9|0|M|6|T|6|2Q|7|35|6|3C|6|3L|5|0|0|0|14|A|0|E|R|B|0|0|X|C|0|0|13|D|0|0|R|E|0|0^^$0|$1|$2|3|4|5|6|$7|8]]|9|$2|3|4|5|6|$7|A]]|B|$2|3|4|5|6|$7|C]]|D|$2|3|4|5|6|$7|E]]|F|$2|3|4|5|6|$7|G]]|H|$2|3|4|5|6|$7|I]]|J|$2|3|4|5|6|$7|K]]|L|$2|3|4|5|6|$7|I]]|M|$2|3|4|5|6|$7|-4]]|N|$2|3|4|5|6|$7|O]]|P|$2|3|4|5|6|$7|Q]]|R|$2|3|4|5|6|$7|S]]|T|$2|3|4|5|6|$7|U]]|V|$2|3|4|5|6|$7|W]]|X|$2|3|4|5|6|$7|Y]]]|Z|@$10|11|12|13|2|14|15|38|16|@$17|39|18|3A|19|1A]|$17|3B|18|3C|19|1A]|$17|3D|18|3E|19|1A]|$17|3F|18|3G|19|1A]|$17|3H|18|3I|19|1A]|$17|3J|18|3K|19|1B]|$17|3L|18|3M|19|1B]|$17|3N|18|3O|19|1B]]|1C|@$17|3P|18|3Q|10|3R]|$17|3S|18|3T|10|3U]|$17|3V|18|3W|10|3X]]|6|$]]|$10|1D|12|1E|2|14|15|3Y|16|@$17|3Z|18|40|19|1A]|$17|41|18|42|19|1A]|$17|43|18|44|19|1A]|$17|45|18|46|19|1A]|$17|47|18|48|19|1A]|$17|49|18|4A|19|1A]|$17|4B|18|4C|19|1A]|$17|4D|18|4E|19|1A]|$17|4F|18|4G|19|1A]|$17|4H|18|4I|19|1B]]|1C|@$17|4J|18|4K|10|4L]]|6|$]]|$10|1F|12|1G|2|14|15|4M|16|@$17|4N|18|4O|19|1A]|$17|4P|18|4Q|19|1A]]|1C|@]|6|$]]|$10|1H|12|1I|2|14|15|4R|16|@$17|4S|18|4T|19|1A]|$17|4U|18|4V|19|1A]]|1C|@]|6|$]]|$10|1J|12|1K|2|14|15|4W|16|@$17|4X|18|4Y|19|1A]]|1C|@]|6|$]]|$10|1L|12|1M|2|14|15|4Z|16|@$17|50|18|51|19|1B]|$17|52|18|53|19|1A]|$17|54|18|55|19|1A]]|1C|@$17|56|18|57|10|58]]|6|$]]|$10|1N|12|1O|2|14|15|59|16|@]|1C|@]|6|$]]|$10|1P|12|1Q|2|14|15|5A|16|@$17|5B|18|5C|19|1A]|$17|5D|18|5E|19|1A]|$17|5F|18|5G|19|1A]|$17|5H|18|5I|19|1A]|$17|5J|18|5K|19|1A]]|1C|@]|6|$]]|$10|1R|12|1S|2|14|15|5L|16|@$17|5M|18|5N|19|1A]|$17|5O|18|5P|19|1A]]|1C|@]|6|$]]|$10|1T|12|1U|2|14|15|5Q|16|@$17|5R|18|5S|19|1A]|$17|5T|18|5U|19|1A]|$17|5V|18|5W|19|1A]|$17|5X|18|5Y|19|1A]]|1C|@]|6|$]]|$10|1V|12|1W|2|1X|15|5Z|16|@]|1C|@]|6|$1Y|1Z]]|$10|20|12|21|2|14|15|60|16|@]|1C|@]|6|$]]|$10|22|12|23|2|14|15|61|16|@$17|62|18|63|19|1A]|$17|64|18|65|19|1A]|$17|66|18|67|19|1A]|$17|68|18|69|19|1A]|$17|6A|18|6B|19|1A]|$17|6C|18|6D|19|1A]]|1C|@$17|6E|18|6F|10|6G]]|6|$]]|$10|24|12|25|2|14|15|6H|16|@$17|6I|18|6J|19|1A]|$17|6K|18|6L|19|1A]|$17|6M|18|6N|19|1A]]|1C|@]|6|$]]|$10|26|12|27|2|14|15|6O|16|@$17|6P|18|6Q|19|1A]|$17|6R|18|6S|19|1A]|$17|6T|18|6U|19|1A]|$17|6V|18|6W|19|1A]|$17|6X|18|6Y|19|1A]]|1C|@$17|6Z|18|70|10|71]]|6|$]]|$10|28|12|29|2|14|15|72|16|@$17|73|18|74|19|1A]]|1C|@]|6|$]]|$10|2A|12|2B|2|14|15|75|16|@$17|76|18|77|19|1A]|$17|78|18|79|19|1A]]|1C|@]|6|$]]|$10|2C|12|2D|2|14|15|7A|16|@$17|7B|18|7C|19|1A]|$17|7D|18|7E|19|1A]|$17|7F|18|7G|19|1A]]|1C|@]|6|$]]|$10|2E|12|2F|2|14|15|7H|16|@$17|7I|18|7J|19|1A]]|1C|@]|6|$]]|$10|2G|12|2H|2|14|15|7K|16|@$17|7L|18|7M|19|1A]]|1C|@]|6|$]]|$10|2I|12|2J|2|14|15|7N|16|@]|1C|@$17|7O|18|7P|10|7Q]]|6|$]]|$10|2K|12|2L|2|14|15|7R|16|@$17|7S|18|7T|19|1A]|$17|7U|18|7V|19|1A]]|1C|@]|6|$]]|$10|2M|12|2N|2|14|15|7W|16|@$17|7X|18|7Y|19|1A]|$17|7Z|18|80|19|1A]|$17|81|18|82|19|1A]|$17|83|18|84|19|1A]]|1C|@]|6|$]]|$10|2O|12|2P|2|14|15|85|16|@$17|86|18|87|19|1A]|$17|88|18|89|19|1A]|$17|8A|18|8B|19|1A]|$17|8C|18|8D|19|1A]|$17|8E|18|8F|19|1A]]|1C|@$17|8G|18|8H|10|8I]|$17|8J|18|8K|10|8L]]|6|$]]|$10|2Q|12|2R|2|14|15|8M|16|@$17|8N|18|8O|19|1A]|$17|8P|18|8Q|19|1A]|$17|8R|18|8S|19|1A]|$17|8T|18|8U|19|1A]|$17|8V|18|8W|19|1A]|$17|8X|18|8Y|19|1A]]|1C|@]|6|$]]|$10|2S|12|2T|2|14|15|8Z|16|@]|1C|@]|6|$]]|$10|2U|12|2V|2|2W|15|90|16|@]|1C|@$17|91|18|92|10|93]]|6|$]]|$10|2X|12|2Y|2|2W|15|94|16|@]|1C|@$17|95|18|96|10|97]]|6|$]]|$10|2Z|12|30|2|2W|15|98|16|@]|1C|@$17|99|18|9A|10|9B]]|6|$]]|$10|31|12|32|2|2W|15|9C|16|@]|1C|@$17|9D|18|9E|10|9F]]|6|$]]|$10|33|12|34|2|2W|15|9G|16|@]|1C|@$17|9H|18|9I|10|9J]]|6|$]]|$10|35|12|-4|2|36|15|9K|16|@]|1C|@]|6|$]]|$10|37|12|-4|2|14|15|9L|16|@]|1C|@]|6|$]]]]

<h2><code>&lt;p:commandXxx process&gt;</code> <code>&lt;p:ajax process&gt;</code> <code>&lt;f:ajax execute&gt;</code></h2>
The <code>process</code> attribute is server side and can only affect <a href="http://docs.oracle.com/javaee/7/api/javax/faces/component/UIComponent.html" rel="noreferrer"><code>UIComponent</code></a>s implementing <a href="http://docs.oracle.com/javaee/7/api/javax/faces/component/EditableValueHolder.html" rel="noreferrer"><code>EditableValueHolder</code></a> (input fields) or <a href="http://docs.oracle.com/javaee/7/api/javax/faces/component/ActionSource.html" rel="noreferrer"><code>ActionSource</code></a> (command fields). The <code>process</code> attribute tells JSF, using a space-separated list of client IDs, which components exactly must be processed through the entire JSF lifecycle upon (partial) form submit.
JSF will then apply the request values (finding HTTP request parameter based on component's own client ID and then either setting it as submitted value in case of <code>EditableValueHolder</code> components or queueing a new <a href="http://docs.oracle.com/javaee/7/api/javax/faces/event/ActionEvent.html" rel="noreferrer"><code>ActionEvent</code></a> in case of <code>ActionSource</code> components), perform conversion, validation and updating the model values (<code>EditableValueHolder</code> components only) and finally invoke the queued <code>ActionEvent</code> (<code>ActionSource</code> components only). JSF will skip processing of all other components which are not covered by <code>process</code> attribute. Also, components whose <code>rendered</code> attribute evaluates to <code>false</code> during apply request values phase will also be skipped as part of safeguard against tampered requests.
Note that it's in case of <code>ActionSource</code> components (such as <code>&lt;p:commandButton&gt;</code>) very important that you also include the component itself in the <code>process</code> attribute, particularly if you intend to invoke the action associated with the component. So the below example which intends to process only certain input component(s) when a certain command component is invoked ain't gonna work:
<pre><code>&lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; /&gt;
&lt;p:commandButton process=&quot;foo&quot; action=&quot;#{bean.action}&quot; /&gt;
</code></pre>
It would only process the <code>#{bean.foo}</code> and not the <code>#{bean.action}</code>. You'd need to include the command component itself as well:
<pre><code>&lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; /&gt;
&lt;p:commandButton process=&quot;@this foo&quot; action=&quot;#{bean.action}&quot; /&gt;
</code></pre>
Or, as you apparently found out, using <code>@parent</code> if they happen to be the only components having a common parent:
<pre><code>&lt;p:panel&gt;&lt;!-- Type doesn't matter, as long as it's a common parent. --&gt;
 &lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; /&gt;
 &lt;p:commandButton process=&quot;@parent&quot; action=&quot;#{bean.action}&quot; /&gt;
&lt;/p:panel&gt;
</code></pre>
Or, if they both happen to be the only components of the parent <a href="http://docs.oracle.com/javaee/7/api/javax/faces/component/UIForm.html" rel="noreferrer"><code>UIForm</code></a> component, then you can also use <code>@form</code>:
<pre><code>&lt;h:form&gt;
 &lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; /&gt;
 &lt;p:commandButton process=&quot;@form&quot; action=&quot;#{bean.action}&quot; /&gt;
&lt;/h:form&gt;
</code></pre>
This is sometimes undesirable if the form contains more input components which you'd like to skip in processing, more than often in cases when you'd like to update another input component(s) or some UI section based on the current input component in an ajax listener method. You namely don't want that validation errors on other input components are preventing the ajax listener method from being executed.
Then there's the <code>@all</code>. This has no special effect in <code>process</code> attribute, but only in <code>update</code> attribute. A <code>process=&quot;@all&quot;</code> behaves exactly the same as <code>process=&quot;@form&quot;</code>. HTML doesn't support submitting multiple forms at once anyway.
There's by the way also a <code>@none</code> which may be useful in case you absolutely don't need to process anything, but only want to update some specific parts via <code>update</code>, particularly those sections whose content doesn't depend on submitted values or action listeners.
Noted should be that the <code>process</code> attribute has no influence on the HTTP request payload (the amount of request parameters). Meaning, the default HTML behavior of sending &quot;everything&quot; contained within the HTML representation of the <code>&lt;h:form&gt;</code> will be not be affected. In case you have a large form, and want to reduce the HTTP request payload to only these absolutely necessary in processing, i.e. only these covered by <code>process</code> attribute, then you can set the <code>partialSubmit</code> attribute in PrimeFaces Ajax components as in <code>&lt;p:commandXxx ... partialSubmit=&quot;true&quot;&gt;</code> or <code>&lt;p:ajax ... partialSubmit=&quot;true&quot;&gt;</code>. You can also configure this 'globally' by editing <code>web.xml</code> and add
<pre><code>&lt;context-param&gt;
 &lt;param-name&gt;primefaces.SUBMIT&lt;/param-name&gt;
 &lt;param-value&gt;partial&lt;/param-value&gt;
&lt;/context-param&gt;
</code></pre>
Alternatively, you can also use <a href="http://showcase.omnifaces.org/components/form" rel="noreferrer"><code>&lt;o:form&gt;</code></a> of OmniFaces 3.0+ which defaults to this behavior.
The standard JSF equivalent to the PrimeFaces specific <code>process</code> is <code>execute</code> from <code>&lt;f:ajax execute&gt;</code>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the <code>@parent</code> keyword. Also, it may be useful to know that <code>&lt;p:commandXxx process&gt;</code> defaults to <code>@form</code> while <code>&lt;p:ajax process&gt;</code> and <code>&lt;f:ajax execute&gt;</code> defaults to <code>@this</code>. Finally, it's also useful to know that <code>process</code> supports the so-called &quot;PrimeFaces Selectors&quot;, see also <a href="https://stackoverflow.com/questions/20080861/how-do-primefaces-selectors-as-in-update-myclass-work">How do PrimeFaces Selectors as in update=&quot;@(.myClass)&quot; work?</a>
<hr />
<h2><code>&lt;p:commandXxx update&gt;</code> <code>&lt;p:ajax update&gt;</code> <code>&lt;f:ajax render&gt;</code></h2>
The <code>update</code> attribute is client side and can affect the HTML representation of all <code>UIComponent</code>s. The <code>update</code> attribute tells JavaScript (the one responsible for handling the ajax request/response), using a space-separated list of client IDs, which parts in the HTML DOM tree need to be updated as response to the form submit.
JSF will then prepare the right ajax response for that, containing only the requested parts to update. JSF will skip all other components which are not covered by <code>update</code> attribute in the ajax response, hereby keeping the response payload small. Also, components whose <code>rendered</code> attribute evaluates to <code>false</code> during render response phase will be skipped. Note that even though it would return <code>true</code>, JavaScript cannot update it in the HTML DOM tree if it was initially <code>false</code>. You'd need to wrap it or update its parent instead. See also <a href="https://stackoverflow.com/questions/14790014">Ajax update/render does not work on a component which has rendered attribute</a>.
Usually, you'd like to update only the components which really need to be &quot;refreshed&quot; in the client side upon (partial) form submit. The example below updates the entire parent form via <code>@form</code>:
<pre><code>&lt;h:form&gt;
 &lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;foo_m&quot; for=&quot;foo&quot; /&gt;
 &lt;p:inputText id=&quot;bar&quot; value=&quot;#{bean.bar}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;bar_m&quot; for=&quot;bar&quot; /&gt;
 &lt;p:commandButton action=&quot;#{bean.action}&quot; update=&quot;@form&quot; /&gt;
&lt;/h:form&gt;
</code></pre>
(note that <code>process</code> attribute is omitted as that defaults to <code>@form</code> already)
Whilst that may work fine, the update of input and command components is in this particular example unnecessary. Unless you change the model values <code>foo</code> and <code>bar</code> inside <code>action</code> method (which would in turn be unintuitive in UX perspective), there's no point of updating them. The message components are the only which really need to be updated:
<pre><code>&lt;h:form&gt;
 &lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;foo_m&quot; for=&quot;foo&quot; /&gt;
 &lt;p:inputText id=&quot;bar&quot; value=&quot;#{bean.bar}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;bar_m&quot; for=&quot;bar&quot; /&gt;
 &lt;p:commandButton action=&quot;#{bean.action}&quot; update=&quot;foo_m bar_m&quot; /&gt;
&lt;/h:form&gt;
</code></pre>
However, that gets tedious when you have many of them. That's one of the reasons why PrimeFaces Selectors exist. Those message components have in the generated HTML output a common style class of <code>ui-message</code>, so the following should also do:
<pre><code>&lt;h:form&gt;
 &lt;p:inputText id=&quot;foo&quot; value=&quot;#{bean.foo}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;foo_m&quot; for=&quot;foo&quot; /&gt;
 &lt;p:inputText id=&quot;bar&quot; value=&quot;#{bean.bar}&quot; required=&quot;true&quot; /&gt;
 &lt;p:message id=&quot;bar_m&quot; for=&quot;bar&quot; /&gt;
 &lt;p:commandButton action=&quot;#{bean.action}&quot; update=&quot;@(.ui-message)&quot; /&gt;
&lt;/h:form&gt;
</code></pre>
(note that you should keep the IDs on message components, otherwise <code>@(...)</code> won't work! Again, see <a href="https://stackoverflow.com/questions/20080861/how-do-primefaces-selectors-as-in-update-myclass-work">How do PrimeFaces Selectors as in update=&quot;@(.myClass)&quot; work?</a> for detail)
The <code>@parent</code> updates only the parent component, which thus covers the current component and all siblings and their children. This is more useful if you have separated the form in sane groups with each its own responsibility. The <code>@this</code> updates, obviously, only the current component. Normally, this is only necessary when you need to change one of the component's own HTML attributes in the action method. E.g.
<pre><code>&lt;p:commandButton action=&quot;#{bean.action}&quot; update=&quot;@this&quot; 
 oncomplete=&quot;doSomething('#{bean.value}')&quot; /&gt;
</code></pre>
Imagine that the <code>oncomplete</code> needs to work with the <code>value</code> which is changed in <code>action</code>, then this construct wouldn't have worked if the component isn't updated, for the simple reason that <code>oncomplete</code> is part of generated HTML output (and thus all EL expressions in there are evaluated during render response).
The <code>@all</code> updates the entire document, which should be used with care. Normally, you'd like to use a true GET request for this instead by either a plain link (<code>&lt;a&gt;</code> or <code>&lt;h:link&gt;</code>) or a redirect-after-POST by <code>?faces-redirect=true</code> or <code>ExternalContext#redirect()</code>. In effects, <code>process=&quot;@form&quot; update=&quot;@all&quot;</code> has exactly the same effect as a non-ajax (non-partial) submit. In my entire JSF career, the only sensible use case I encountered for <code>@all</code> is to display an error page in its entirety in case an exception occurs during an ajax request. See also <a href="https://stackoverflow.com/questions/10449862/what-is-the-correct-way-to-deal-with-jsf-2-0-exceptions-for-ajaxified-components/">What is the correct way to deal with JSF 2.0 exceptions for AJAXified components?</a>
The standard JSF equivalent to the PrimeFaces specific <code>update</code> is <code>render</code> from <code>&lt;f:ajax render&gt;</code>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the <code>@parent</code> keyword. Both <code>update</code> and <code>render</code> defaults to <code>@none</code> (which is, &quot;nothing&quot;).
<hr />
See also:
<ul>
<li><a href="https://stackoverflow.com/questions/8634156">How to find out client ID of component for ajax update/render? Cannot find component with expression &quot;foo&quot; referenced from &quot;bar&quot;</a></li>
<li><a href="https://stackoverflow.com/questions/20146630">Execution order of events when pressing PrimeFaces p:commandButton</a></li>
<li><a href="https://stackoverflow.com/questions/30934671">How to decrease request payload of p:ajax during e.g. p:dataTable pagination</a></li>
<li><a href="https://stackoverflow.com/questions/28236228">How to show details of current row from p:dataTable in a p:dialog and update after save</a></li>
<li><a href="https://stackoverflow.com/questions/7371903">How to use &lt;h:form&gt; in JSF page? Single form? Multiple forms? Nested forms?</a></li>
</ul>

What exactly are <code>process</code> and <code>update</code> in PrimeFaces <code>p:commandXxx</code> components and <code>execute</code> and <code>render</code> in <code>f:ajax</code> tag?

Which works at the time of validation? What does <code>update</code> attribute do rather than updating value to component from back end? Do <code>process</code> attribute bind value to model? What exactly do <code>@this</code>, <code>@parent</code>, <code>@all</code> and <code>@form</code> in both attributes?

The example below is working fine, but I am a little confused in basic concepts.

<pre><code>&lt;p:commandButton process="@parent"
 update="@form"
 action="#{bean.submit}" 
 value="Submit" /&gt;
</code></pre>

Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes

服务器

 到底是什么process和update在PrimeFaces中p:commandXxx组件和execute和render在f:ajax标签？ 在验证时，哪一项有效？什么是update属性而不是将值从后端更新到组件？做process是否将属性值绑定到模型？具体做什么@this，@parent，@all和@form在这两...

问理解PrimeFaces进程/更新和JSF :ajax执行/呈现属性
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问理解PrimeFaces进程/更新和JSF :ajax执行/呈现属性EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问理解PrimeFaces进程/更新和JSF :ajax执行/呈现属性
EN