问题描述
如果我使用JSF Primefaces 7.0渲染xhtml文件以显示用户(括号内的用户名)或用户名(如果用户名为空或为空字符串),那么我希望仅显示不带括号的用户名。
pom.xml:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html
xmlns="http://www.w3.org/1999/xhtml"
xmlns:p="http://primefaces.org/ui"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
User: #{userReport.selectedUser.name} (#{userReport.selectedUser.username})
</html>
所以,现在这就是我正确渲染的东西:
user.xhtml:
User: John Doe (jdoe)
渲染(在网络浏览器内部):
#{userReport.selectedUser.name}
但是,如果User: (jdoe)
为null,则会在括号内显示用户名:
User: jdoe
我需要它来进行这样的渲染(不带括号):
? :
尝试使用三元运算符#{userReport.selectedUser.name ? userReport.selectedUser.name (#{userReport.selectedUser.username}) : #{userReport.selectedUser.username} }
javax.servlet.ServletException: The identifier [#] is not a valid Java identifier as required by section 1.19 of the EL specification (Identifier ::= Java language identifier). This check can be disabled by setting the system property org.apache.el.parser.SKIP_IDENTIFIER_CHECK to true.
at javax.faces.webapp.FacesServlet.executeLifecyle(FacesServlet.java:749)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:475)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:111)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
这将导致以下堆栈跟踪:
User:<c:choose>
<c:when test="#{not empty userReport.selectedUser.name}">
#{userReport.selectedUser.name} ({userReport.selectedUser.username})
</c:when>
<c:otherwise>
#{userReport.selectedUser.username}
</c:otherwise>
</c:choose>
使用以下方法解决:
? :
有没有一种更简单的方法来做到这一点?例如,使用三元select LOG_DATE,ITEM_ID,PROBLEM,(case when row_number() over (partition by CALL_DATE,UCID,ID,ACCOUNT_NO,CALL_STATUS order by log_date desc) = 1
then call_date
end) as call_date,CALL_STATUS order by log_date desc) = 1
then ucid
end) as ucid,. . .
from t;
运算符?
解决方法
使用? :
三元运算符和+=
串联运算符使它工作:
User: #{!empty(userReport.selectedUser.name) ? userReport.selectedUser.name += ' (' += userReport.selectedUser.username += ')' : userReportView.selectedUser.username}