当我尝试在 Spring MVC 应用程序中显示资源包中的标签时，当我尝试显示值时出现空错误。我使用 spring.ftl 定义了一些 utils 方法。我将其加载到类路径中并且配置没问题。您可以在下面找到我的 html 模板和 Fremmarker 配置。
配置：
private static Configuration getConfig() throws IOException, TemplateException {
// Create your Configuration instance, and specify if up to what FreeMarker
// version (here 2.3.32) do you want to apply the fixes that are not 100%
// backward-compatible. See the Configuration JavaDoc for details.
Configuration cfg = new Configuration(Configuration.VERSION_2_3_32);
// Specify the source where the template files come from. Here I set a
// plain directory for it, but non-file-system sources are possible too:
//cfg.setDirectoryForTemplateLoading(new File("/where/you/store/templates"));
// From here we will set the settings recommended for new projects. These
// aren't the defaults for backward compatibilty.
cfg.setDefaultEncoding("UTF-8");
// Sets how errors will appear.
// During web page *development* TemplateExceptionHandler.HTML_DEBUG_HANDLER is better.
cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
// Don't log exceptions inside FreeMarker that it will thrown at you anyway:
cfg.setLogTemplateExceptions(false);
// Wrap unchecked exceptions thrown during template processing into TemplateException-s:
cfg.setWrapUncheckedExceptions(true);
// Do not fall back to higher scopes when reading a null loop variable:
cfg.setFallbackOnNullLoopVariable(false);
cfg.setTemplateLoader(new ClassTemplateLoader(DocGeneratorUtils.class, "/templates"));
Properties settings = new Properties();
settings.setProperty("auto_import", "/spring.ftl as spring");
cfg.setSettings(settings);
return cfg;
}
HTML 模板：
<#import "/spring.ftl" as spring/>
<!DOCTYPE html>
<html>
<body>
<@spring.message "resource.bundle.key"/>
</body>
</html>
错误：
The following has evaluated to null or missing:
==> springMacroRequestContext [in template "spring.ftl" at line 28, column 24]
----
Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (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: ${springMacroRequestContext.getMessag... [in template "spring.ftl" in macro "message" at line 28, column 22]
- Reached through: @spring.message "sale.enum.TravelPass... [in template "MY_TEMPLATE" at line 7, column 9]
----
FreeMarker template error:
The following has evaluated to null or missing:
==> springMacroRequestContext [in template "spring.ftl" at line 28, column 24]
----
Tip: If the failing expression is known to legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (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: ${springMacroRequestContext.getMessag... [in template "spring.ftl" in macro "message" at line 28, column 22]
- Reached through: @spring.message "resource.bundle.key... [in template "MY_TEMPLATE" at line 53, column 9]
----
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.UnexpectedTypeException.newDescriptionBuilder(UnexpectedTypeException.java:85)
at freemarker.core.UnexpectedTypeException.<init>(UnexpectedTypeException.java:48)
at freemarker.core.NonHashException.<init>(NonHashException.java:49)
at freemarker.core.Dot._eval(Dot.java:48)
非常有趣的信息。感谢分享。