错误
Could not find artifact com.oracle:ojdbc6:pom:11.2.0.4 in central (https://repo.maven.apache.org/maven2)
原因
OJDBC6的Maven代码groupId写错了，正确的如下
<!-- https://mvnrepository.com/artifact/com.oracle.database.jdbc/ojdbc6 -->
<dependency>
<groupId>com.oracle.database.jdbc</groupId>
<artifactId>ojdbc6</artifactId>
<version>11.2.0.4</version>
</dependency>