唯有热爱，能抵漫长岁月

Think Big, Act Small

    • when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? ---- ---- FTL stack trace ("~" means nesting-related): - Failed at: ${((tag.thumbnail)?length > 0)?string... [in template "themes/halo-theme-sakura/tag.ftl" at line 13, column 49] ~ Reached through: #nested [in template "themes/halo-theme-sakura/header.ftl" in macro "header" at line 100, column 17] ~ Reached through: @header title="标签：${tag.name!} - ${bl... [in template "themes/halo-theme-sakura/tag.ftl" at line 7, column 1] ---- Java stack trace (for programmers): ---- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:134) at freemarker.core.EvalUtil.coerceModelToTextualCommon(EvalUtil.java:481) at freemarker.core.EvalUtil.coerceModelToStringOrUnsupportedMarkup(EvalUtil.java:434) at freemarker.core.Expression.evalAndCoerceToStringOrUnsupportedMarkup(Expression.java:139) at freemarker.core.BuiltInForString.getTargetString(BuiltInForString.java:34) at freemarker.core.BuiltInForString._eval(BuiltInForString.java:29) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.EvalUtil.compare(EvalUtil.java:113) at freemarker.core.ComparisonExpression.evalToBoolean(ComparisonExpression.java:78) at freemarker.core.BooleanExpression._eval(BooleanExpression.java:30) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.ParentheticalExpression._eval(ParentheticalExpression.java:50) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.BuiltInsForMultipleTypes$stringBI._eval(BuiltInsForMultipleTypes.java:765) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.MethodCall._eval(MethodCall.java:55) at freemarker.core.Expression.eval(Expression.java:101) at freemarker.core.DollarVariable.calculateInterpolatedStringOrMarkup(DollarVariable.java:100) at freemarker.core.DollarVariable.accept(DollarVariable.java:63) at freemarker.core.Environment.visit(Environment.java:347) at freemarker.core.Environment.visit(Environment.java:353) at freemarker.core.Environment.visit(Environment.java:389) at freemarker.core.Environment.invokeNestedContent(Environment.java:633) at freemarker.core.BodyInstruction.accept(BodyInstruction.java:60) at freemarker.core.Environment.visit(Environment.java:383) at freemarker.core.Environment.invokeMacroOrFunctionCommonPart(Environment.java:889) at freemarker.core.Environment.invokeMacro(Environment.java:825) at freemarker.core.UnifiedCall.accept(UnifiedCall.java:84) at freemarker.core.Environment.visit(Environment.java:347) at freemarker.core.Environment.visit(Environment.java:353) at freemarker.core.Environment.process(Environment.java:326) at freemarker.template.Template.process(Template.java:383) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.processTemplate(FreeMarkerView.java:391) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.doRender(FreeMarkerView.java:304) at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel(FreeMarkerView.java:255) at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel(AbstractTemplateView.java:179) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:316) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1396) at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1141) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1080) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) at javax.servlet.http.HttpServlet.service(HttpServlet.java:497) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) at javax.servlet.http.HttpServlet.service(HttpServlet.java:584) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799) at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1626) at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:228) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:103) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:103) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at run.halo.app.security.filter.ContentFilter.doAuthenticate(ContentFilter.java:59) at run.halo.app.security.filter.AbstractAuthenticationFilter.doFilterInternal(AbstractAuthenticationFilter.java:229) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at run.halo.app.filter.CorsFilter.doFilter(CorsFilter.java:53) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at run.halo.app.filter.LogFilter.doFilterInternal(LogFilter.java:40) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193) at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:548) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:602) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1435) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1350) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) at org.eclipse.jetty.server.Server.handle(Server.java:516) at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:388) at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:633) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:380) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105) at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:882) at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1036) at java.base/java.lang.Thread.run(Thread.java:833)