当第一页使用与第二页相同的托管bean时，f:viewParam是否仅在url中传递查询字符串? [英] Does f:viewParam only pass query string in url when first page uses the same managed bean as the second page?
问题描述
例如，使用搜索页面和结果页面.如果我有一个ViewScoped bean来处理我的搜索页面和结果页面，则可以使用类似以下内容的URL传递参数:
Let's use a search page and a results page for example. If i have a ViewScoped bean that handles my search page and my results page, i'm able to pass parameters through the url using something like this:
search.xhtml
search.xhtml
<p:commandButton value="Search" type="submit" action="#{searchBacker.search}" >
支持bean
@ManagedBean(name="search")
@ViewScoped
public class searchBacker extends AbstractBacking {
private String firstName = null;
private String lastName = null;
private String results = null;
public String search() {
return "results?faces-redirect=true&includeViewParams=true";
}
public void getResults() {
MyDAO dao = new MyDAO();
results = dao.getResults(firstName, lastName);
}
//getters and setters
}
results.xhtml
results.xhtml
<f:metadata>
<f:event type="preRenderView" listener="#{searchBacker.getResults}" />
<f:viewParam name="firstName" value="#{searchBacker.firstName}"/>
<f:viewParam name="lastName" value="#{searchBacker.lastName}"/>
</f:metadata>
现在让我说我有两个托管bean-一个用于搜索页面，一个用于结果页面.
Now lets say i have two managed beans - one for the search page and one for the results page.
查询字符串是否仍将使用两个不同的托管Bean构建在url中，还是仅在两个页面都使用相同的托管Bean时才起作用?
Will the query string still be built in the url with 2 different managed beans or does this only work when using the same managed bean for both pages?
更新
在search.xhtml和results.xhtml页面上，我具有相同的<f:viewParam>，但是唯一的区别是，我的f:viewParam value指向的results.xhtml中的支持者与search.xhtml中的支持者不同.当我这样做时，没有参数通过URL传递.当我将result.xhtml中的f:viewParam value指向与search.xhtml中使用的相同的支持者时，参数可以很好地通过url传递，但是该值在我需要的结果支持者中不存在.如果我的results.xhtml页面中有重复的f:viewParam-一个带有搜索支持者，另一个带有结果支持者，则一切正常.两个托管Bean拥有2个相同的f:viewParam是正确的方法吗?
I have the same <f:viewParam> on my search.xhtml and results.xhtml page, but the only difference is that my f:viewParam value points to a different backer in my results.xhtml than in my search.xhtml. When i do this, no params get passed through the url. When I point my f:viewParam value in results.xhtml to the same backer that i use in search.xhtml, the param gets passed through the url just fine, but the value doesn't exist in the results backer where i need it. If i have duplicate f:viewParams in my results.xhtml page - one with the search backer and one with the results backer, everything works fine. Is having 2 of the same f:viewParams with both managed beans the correct way to do this?
示例:
results.xhtml-参数通过url传递，但在我的resultsBacker中不可用
results.xhtml - params get passed through url, but are not available in my resultsBacker
<f:metadata>
<f:viewParam name="firstName" value="#{searchBacker.firstName}"/>
<f:viewParam name="lastName" value="#{searchBacker.lastName}"/>
</f:metadata>
results.xhtml-网址不传递任何参数
results.xhtml - no params get passed through url
<f:metadata>
<f:viewParam name="firstName" value="#{resultsBacker.firstName}"/>
<f:viewParam name="lastName" value="#{resultsBacker.lastName}"/>
</f:metadata>
results.xhtml-参数通过url传递，并且可以在我的resultsBacker中使用，但看起来很笨重.这是执行此操作的正确方法还是我仍然缺少某些东西?
results.xhtml - params get passed through url and are available in my resultsBacker, but seems clunky. Is this the correct way to do this or am i still missing something?
<f:metadata>
<f:viewParam name="firstName" value="#{searchBacker.firstName}"/>
<f:viewParam name="firstName" value="#{resultsBacker.firstName}"/>
<f:viewParam name="lastName" value="#{searchBacker.lastName}"/>
<f:viewParam name="lastName" value="#{resultsBacker.lastName}"/>
</f:metadata>
推荐答案
includeViewParams仅在源视图和目标视图均具有声明为<f:viewParam>的所需视图参数时都有效.
includeViewParams works only if both the source and target view have the desired view parameters declared as <f:viewParam>.
因此，在您的parituclar案例中，您需要在search.xhtml和results.xhtml中都放入具有相同name的<f:viewParam>.在幕后，includeViewParams即仅获取当前视图的视图参数，然后仅应用在目标视图中声明了 的那些参数.
So, in your parituclar case, you need to put the <f:viewParam>s with very same name in both the search.xhtml and results.xhtml. Under the covers, the includeViewParams namely only grabs the view params of the current view and then only applies the ones which are also declared in the target view.
无关与具体问题无关，您似乎实际上想要一个GET表单.在那种情况下，有一种比用参数执行POST-Redirect-GET更好的方法.请查看上方另请参阅"链接的底部.
Unrelated to the concrete problem, you seem to effectively want a GET form. In that case, there is a better way for that than performing a POST-Redirect-GET with parameters. Look at the bottom of the above "See also" link.
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