Spring applies external properties file to configure context error

The wildcard match in the Spring configuration file is comprehensive, but it is not possible to find the declaration of the element ' Context:property-placeholder ', which is basically the DTD parsing file that we did not introduce correctly when we introduced the namespace. Of course you have to import the appropriate package of spring into the correct case.
The solution is as follows:
xmlns:context= "Http://www.springframework.org/schema/context"
Also add a context-dependent parsing file to the Xsi:schemalocation string
Http://www.springframework.org/schema/context
Http://www.springframework.org/schema/context/spring-context-4.2.xsd.
Other such as Util namespace import way, just change the context to the corresponding util on it.

Spring applies external properties file to configure context error