现象

Error running 'App'
Command line is too long. In order to reduce its length classpath file can be used.
Would you like to enable classpath file mode for all run configurations of your project?

解决办法

办法一

.idea\workspace.xml ——>  <component name="PropertiesComponent"> ，在标签里加一行 
<property name="dynamic.classpath" value="true" />

办法二