nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'freemarkEngine' defined in class path resource [conf/app-resources.xml]: Cannot resolve reference to bean 'freemarkerConfiguration' while setting bean property 'configuration';
nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'freemarkerConfiguration' defined in class path resource [conf/app-resources.xml]:
Invocation of init method failed;
nested exception is java.lang.NoSuchFieldError: DEFAULT_INCOMPATIBLE_IMPROVEMENTS

版本不对。使用新版本：
<!-- https://mvnrepository.com/artifact/org.freemarker/freemarker -->
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.23</version>
</dependency>


而不是：
                <dependency>
<groupId>freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.9</version>
</dependency>