如何将参数传递给渲染的属性? [英] How to pass a parameter into rendered attribute?

问题描述

我尝试像这样将参数传递给admin方法:

I try to pass a parameter into method admin like this:

<p:toolbarGroup align="right" rendered="#{loginBean.admin('dataread'}">
                            <h:form>
                                <p:commandButton value="manage users" ajax="false"
                                                 icon="ui-icon-document" action="/admin/manageUsers.xhtml?faces-redirect=true"/>
                            </h:form>
                        </p:toolbarGroup>

我的托管Bean中的代码就是这样

the code in my managed Bean is like that

public boolean isAdmin(String role){
          FacesContext facesContext = FacesContext.getCurrentInstance();
          HttpServletRequest request = (HttpServletRequest) FacesContext.getCurrentInstance().getExternalContext().getRequest();
          return request.isUserInRole("admin");                
          }

推荐答案

rendered="#{loginBean.admin('dataread'}"

您在那里缺少)一个EL语法错误，该错误导致该值未被识别为EL表达式，因此被视为纯香草字符串，该字符串将在rendered属性中使用，因此默认为boolean true.另外，当指定动作表达式(例如#{bean.method()})而不是值表达式(例如#{bean.property})时，您应该指定完整的方法名称，因此要指定isAdmin()而不是admin().

You've there with the missing ) an EL syntax error which causes the value not being recognized as an EL expression and is thus treated as a plain vanilla string which would in the rendered attribute thus default to boolean true. Also, when specifying action expressions like #{bean.method()} instead of value expressions like #{bean.property}, you should specify the full method name, thus isAdmin() instead of admin().

所有，这应该做到:

rendered="#{loginBean.isAdmin('dataread')}"

---

与具体问题无关，#{request}已经在EL作用域中提供了HttpServletRequest，因此也不需要支持bean样板:

---

Unrelated to the concrete problem, the HttpServletRequest is already available in the EL scope by #{request}, so this should also do without the need for backing bean boilerplate:

rendered="#{request.isUserInRole('admin')}"

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