maven中出现 ‘dependencies.dependency.version‘ for xxxx:jar is missing

mvn clean后，出现下面的log

[INFO] Scanning for projects...

[ERROR] [ERROR] Some problems were encountered while processing the POMs:

[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-nop:jar is missing. @ com.henry.flink:DataClean:[unknown-version], /home/appleyuchi/桌面/Flink_Code/flink清洗数据案例/FlinkProj/DataClean/pom.xml, line 57, column 21

@

[ERROR] The build could not read 1 project -> [Help 1]

[ERROR]

[ERROR] The project com.henry.flink:DataClean:1.0-SNAPSHOT (/home/appleyuchi/桌面/Flink_Code/flink清洗数据案例/FlinkProj/DataClean/pom.xml) has 1 error

[ERROR] 'dependencies.dependency.version' for org.slf4j:slf4j-nop:jar is missing. @ com.henry.flink:DataClean:[unknown-version], /home/appleyuchi/桌面/Flink_Code/flink清洗数据案例/FlinkProj/DataClean/pom.xml, line 57, column 21

[ERROR]

[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.

[ERROR] Re-run Maven using the -X switch to enable full debug logging.

[ERROR]

[ERROR] For more information about the errors and possible solutions, please read the following articles:

[ERROR] [Help 1] /confluence/display/MAVEN/ProjectBuildingException

Process finished with exit code 1

原因：

这个原因是因为父pom中定义了子pom中的版本，

当删除 父pom中的内容时，就会导致子pom所在的工程执行mvn出现上述版本消失的报错。