FreeMarker template error!
Expression introID is undefined on line 15, column 51 in tpl/2015/p/www.pusaite.net/about.html.The problematic instruction:----------==> ${introID} [on line 15, column 49 in tpl/2015/p/www.pusaite.net/about.html] in user-directive mytag.viewIntroduce [on line 15, column 1 in tpl/2015/p/www.pusaite.net/about.html]----------Java backtrace for programmers:----------freemarker.core.InvalidReferenceException: Expression introID is undefined on line 15, column 51 in tpl/2015/p/www.pusaite.net/about.html.at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)at freemarker.core.Expression.getStringValue(Expression.java:118)at freemarker.core.Expression.getStringValue(Expression.java:93)at freemarker.core.DollarVariable.accept(DollarVariable.java:76)at freemarker.core.Environment.visit(Environment.java:245)at freemarker.core.MixedContent.accept(MixedContent.java:92)at freemarker.core.Environment.visit(Environment.java:245)at freemarker.core.Environment.renderElementToString(Environment.java:1510)at freemarker.core.StringLiteral.getStringValue(StringLiteral.java:95)at freemarker.core.StringLiteral._getAsTemplateModel(StringLiteral.java:80)at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)at freemarker.core.UnifiedCall.accept(UnifiedCall.java:110)at freemarker.core.Environment.visit(Environment.java:245)at freemarker.core.MixedContent.accept(MixedContent.java:92)at freemarker.core.Environment.visit(Environment.java:245)at freemarker.core.Environment.process(Environment.java:225)at freemarker.template.Template.process(Template.java:117)at freemarker.ext.servlet.FreemarkerServlet.process(FreemarkerServlet.java:310)at freemarker.ext.servlet.FreemarkerServlet.doGet(FreemarkerServlet.java:245)at javax.servlet.http.HttpServlet.service(HttpServlet.java:114)at javax.servlet.http.HttpServlet.service(HttpServlet.java:91)at com.caucho.server.dispatch.ServletFilterChain.doFilter(ServletFilterChain.java:103)at shield.front.action.filter.NotAllowedToTunFilesFilter.doFilter(NotAllowedToTunFilesFilter.java:127)at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:87)at shield.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:81)at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:87)at shield.front.action.filter.InvalidXSSFilter.doFilter(InvalidXSSFilter.java:93)at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:87)at com.caucho.filters.GzipFilter.doFilter(GzipFilter.java:169)at com.caucho.server.dispatch.FilterFilterChain.doFilter(FilterFilterChain.java:87)at com.caucho.server.cache.CacheFilterChain.doFilter(CacheFilterChain.java:192)at com.caucho.server.webapp.WebAppFilterChain.doFilter(WebAppFilterChain.java:187)at com.caucho.server.dispatch.ServletInvocation.service(ServletInvocation.java:265)at com.caucho.server.hmux.HmuxRequest.handleRequest(HmuxRequest.java:436)at com.caucho.server.port.TcpConnection.run(TcpConnection.java:682)at com.caucho.util.ThreadPool$Item.runTasks(ThreadPool.java:743)at com.caucho.util.ThreadPool$Item.run(ThreadPool.java:662)at java.lang.Thread.run(Thread.java:662)