Transitive dependencies in the package version conflicts
Regulating principles:
1 path recently, the principle of priority
if the use is version 4.2.4, you can manually add their own dependencies
that this time used the jar is spring-beans 4.2.4
2 first declaration takes precedence over the principles
to be used jar package version in front of the
exclusion principle:
version lock principle
to add the following content in front of the configuration file, lock spring-beans version
if there are multiple versions need to be locked jar package can extract variables
so that the following are the introduction of these jar package can not written version number.
