FreeMarker模板错误：以下内容已评估为null或缺失但不是 [英] FreeMarker template error: The following has evaluated to null or missing | BUT NOT TRUE
问题描述
我面临的错误是如此奇怪。一切看起来都很好，但是当浏览器将GET请求发送到服务器时，我收到此错误。我想要做的是实际捕获HTTP参数，将它们保存在发送到Freemarker模板的ArrayList中保存的对象中。
The error I'm facing is so weird. Everything looks fine, but I get this error when the browser sends the GET request to the server. What I'm trying to do is actually catching the HTTP parameters, save them in an object saved in an ArrayList sending to a Freemarker template.
你能帮帮我吗？非常感谢。
Could you please help me? Thanks a lot.
错误：
freemarker.log._JULLoggerFactory $ JULLogger错误严重：错误
执行FreeMarker模板FreeMarker模板错误：以下
已评估为null或缺失：
==> item.lat1 [in template view / result.ftl第18行，第15列
freemarker.log._JULLoggerFactory$JULLogger error SEVERE: Error executing FreeMarker template FreeMarker template error: The following has evaluated to null or missing: ==> item.lat1 [in template "view/result.ftl" at line 18, column 15]
freemarker.core.InvalidReferenceException：[...异常消息为
已打印;看看上面...]
freemarker.core.InvalidReferenceException.getInstance（InvalidReferenceException.java:131）
at freemarker.core.EvalUtil.coerceModelToString（EvalUtil.java:355）
at
freemarker.core.Expression.evalAndCoerceToString（Expression.java:82）
at freemarker.core.DollarVariable.accept（DollarVariable.java:41）at
freemarker.core.Environment.visit（ Environment.java:324）
freemarker.core.MixedContent.accept（MixedContent.java:54）at
freemarker.core.Environment.visitByHiddingParent（Environment.java:345）
at
freemarker.core.IteratorBlock $ IterationContext.executeNestedBlockInner（IteratorBlock.java:268）
at
freemarker.core.IteratorBlock $ IterationContext.executeNestedBlock（IteratorBlock.java:220）
at
freemarker.core.IteratorBlock $ IterationContext.accept（IteratorBlock.java:194）
at
freemarker.core.Environment.visitIteratorBlock（Environment.java:572)
at
freemarker.core.IteratorBlock.acceptWithResult（IteratorBlock.java:78）
at freemarker.core.IteratorBlock.accept（IteratorBlock.java:64）at
freemarker.core.Environment.visit （Environment.java:324）
freemarker.core.MixedContent.accept（MixedContent.java:54）at
freemarker.core.Environment.visit（Environment.java:324）
freemarker.core.Environment.process（Environment.java:302）at
freemarker.template.Template.process（Template.java:325）at
spark.template.freemarker.FreeMarkerEngine.render（FreeMarkerEngine。 java：71）
at controller.App.lambda $ main $ 1（App.java:57）at
spark.RouteImpl $ 1.handle（RouteImpl.java:58）at
spark.webserver .MatcherFilter.doFilter（MatcherFilter.java:162）at
spark.webserver.JettyHandler.doHandle（JettyHandler.java:61）at
org.eclipse.jetty.server.session.SessionHandler.doScope（SessionHandler） .java：189）
at
org.eclipse.jetty.server.handler.ScopedHan dler.handle（ScopedHandler.java:141）
at
org.eclipse.jetty.server.handler.HandlerWrapper.handle（HandlerWrapper.java:119）
at org.eclipse.jetty。 server.Server.handle（Server.java:517）at
org.eclipse.jetty.server.HttpChannel.handle（HttpChannel.java:302）at
org.eclipse.jetty.server.HttpConnection。 onFillable（HttpConnection.java:242）
at
org.eclipse.jetty.io.AbstractConnection $ ReadCallback.succeeded（AbstractConnection.java:245）
at org.eclipse.jetty.io。 FillInterest.fillable（FillInterest.java:95）
at
org.eclipse.jetty.io.SelectChannelEndPoint $ 2.run（SelectChannelEndPoint.java:75）
at
org.eclipse .jetty.util.thread.strategy.ExecuteProduceConsume.produceAndRun（ExecuteProduceConsume.java:213）
at
org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run（ExecuteProduceConsume.java:147）
at
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob（QueuedThreadPool.java:654）
at
org.eclipse.jetty.util.thread.QueuedThreadPool $ 3.run（QueuedThreadPool.java:572）
at java.lang.Thread.run（Thread.java:745）
freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:131) at freemarker.core.EvalUtil.coerceModelToString(EvalUtil.java:355) at freemarker.core.Expression.evalAndCoerceToString(Expression.java:82) at freemarker.core.DollarVariable.accept(DollarVariable.java:41) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.MixedContent.accept(MixedContent.java:54) at freemarker.core.Environment.visitByHiddingParent(Environment.java:345) at freemarker.core.IteratorBlock$IterationContext.executeNestedBlockInner(IteratorBlock.java:268) at freemarker.core.IteratorBlock$IterationContext.executeNestedBlock(IteratorBlock.java:220) at freemarker.core.IteratorBlock$IterationContext.accept(IteratorBlock.java:194) at freemarker.core.Environment.visitIteratorBlock(Environment.java:572) at freemarker.core.IteratorBlock.acceptWithResult(IteratorBlock.java:78) at freemarker.core.IteratorBlock.accept(IteratorBlock.java:64) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.MixedContent.accept(MixedContent.java:54) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.Environment.process(Environment.java:302) at freemarker.template.Template.process(Template.java:325) at spark.template.freemarker.FreeMarkerEngine.render(FreeMarkerEngine.java:71) at controller.App.lambda$main$1(App.java:57) at spark.RouteImpl$1.handle(RouteImpl.java:58) at spark.webserver.MatcherFilter.doFilter(MatcherFilter.java:162) at spark.webserver.JettyHandler.doHandle(JettyHandler.java:61) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:189) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:119) at org.eclipse.jetty.server.Server.handle(Server.java:517) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:302) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:242) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:245) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95) at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:75) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceAndRun(ExecuteProduceConsume.java:213) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:147) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:654) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:572) at java.lang.Thread.run(Thread.java:745)
[qtp285763673-17]错误spark.webserver.MatcherFilter -
java.lang.IllegalArgumentException：
freemarker.core.InvalidReferenceException：以下评估
为null或缺失：
==> item.lat1 [在模板view / result.ftl第18行第15列]
[qtp285763673-17] ERROR spark.webserver.MatcherFilter - java.lang.IllegalArgumentException: freemarker.core.InvalidReferenceException: The following has evaluated to null or missing: ==> item.lat1 [in template "view/result.ftl" at line 18, column 15]
..但是的确如此，因为我打印数组并且工作正常！
.. But true, because I do print the Array and it works fine!
final FreeMarkerEngine freeMarkerEngine = new FreeMarkerEngine();
final Configuration freeMarkerConfiguration = new Configuration();
freeMarkerConfiguration.setTemplateLoader(new ClassTemplateLoader(App.class, "/"));
freeMarkerEngine.setConfiguration(freeMarkerConfiguration);
get("/rest", (request, response) -> {
Double lat1 = Double.parseDouble(request.queryParams("lat1") != null ? request.queryParams("lat1") : "anonymous");
Double lon1 = Double.parseDouble(request.queryParams("lon1") != null ? request.queryParams("lon1") : "anonymous");
Double lat2 = Double.parseDouble(request.queryParams("lat2") != null ? request.queryParams("lat2") : "anonymous");
Double lon2 = Double.parseDouble(request.queryParams("lon2") != null ? request.queryParams("lon2") : "anonymous");
if (shouldReturnHtml(request)) {
response.status(200);
response.type("text/html");
Map<String, Object> attributes = new HashMap<>();
attributes.put("list",loadTheList(lat1,lon1,lat2,lon2));
return freeMarkerEngine.render(new ModelAndView(attributes, "/view/result.ftl"));
}
else {
response.status(200);
response.type("application/json");
return null;
}
});
}
private static boolean shouldReturnHtml(Request request) {
String accept = request.headers("Accept");
return accept != null && accept.contains("text/html");
}
public static ArrayList<Bereken> loadTheList(double lat1, double lon1, double lat2, double lon2) {
ArrayList<Bereken> list = new ArrayList<>();
list.add(new Bereken(lat1,lon1,lat2,lon2));
return list;
}
并且result.ftl：
And result.ftl:
<#list list as item>
<h2>${item.lat1}</h2>
<h2>${item.lon1}</h2>
<h2>${item.lat2}</h2>
<h2>${item.lon2}</h2>
</#list>
推荐答案
您正在向Bereken类添加1个实例清单。
所以我假设Bereken类不提供公共属性lat1，lat2，lon1，lon2或相应的getter方法。
You are adding 1 instance of the Bereken class to the "list". So i would assume the Bereken class does not provide public properties lat1, lat2, lon1, lon2 or coresponding getter methods.
这篇关于FreeMarker模板错误：以下内容已评估为null或缺失但不是的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
