在改造一个旧项目中，遇到各种问题。
旧项目有十多个模块，因为没有一个统一的父pom，它们对第三方的jar的版本没有统一。 虽然也存在公共的依赖模块，比如commons、util，但是，我们的模块中，有时候又会自己重复引用一些基础的、已经在公共依赖模块存在的对三方jar， 这样 就造成了很多的冲突。
当我考虑统一到一个父pom里面去的时候，发现了很多问题。
1
[ERROR]
[ERROR] The project com.wisdom:mint:1.0-SNAPSHOT (F:\dev\SVN\code\mint\pom.xml) has 1 error
[ERROR] Non-resolvable import POM: Could not transfer artifact io.netty:netty-bom:pom:3.6.10.Final from/to wisdom-public (http://192.168.1.95:8081/repository/wisdom-test67/): Failed to transfer file: http://192.168.1.95:8081/repository/wisdom-test67/io/netty/netty-bom/3.6.10.Final/netty-bom-3.6.10.Final.pom. Return code is: 400 , ReasonPhrase:Repository version policy: SNAPSHOT does not allow version: 3.6.10.Final. @ org.springframework.boot:spring-boot-dependencies:2.1.0.RELEASE, C:\Users\rx63\.m2\repository\org\springframework\boot\spring-boot-dependencies\2.1.0.RELEASE\spring-boot-dependencies-2.1.0.RELEASE.pom, line 988, column 25 -> [Help 2]
[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]
3.6.10.Final.是什么东东，发现是 子模块中写死的一个 property， 虽然没有在 dependency中使用它，但是它却生效了，真是神奇了。 大概是它把 spring-boot 的同名的 property 覆盖了吧， 但是 spring-boot 的当前版本依赖的netty 并不是 3.6.10.Final.， 所以就出现了这个问题。
怎么解决： 把3.6.10.Final. 的property 删除掉就好了。不过呢，“SNAPSHOT does not allow version” 是啥？ 搞不懂
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project mint: Could not resolve dependencies for project com.wisdom:mint:jar:1.0-SNAPSHOT: Failed to collect dependencies at org.springframework.boot:spring-boot-starter-web:jar:2.1.0.RELEASE -> org.hibernate.validator:hibernate-validator:jar:5.4.1.Final: Failed to read artifact descriptor for org.hibernate.validator:hibernate-validator:jar:5.4.1.Final: Could not transfer artifact org.hibernate.validator:hibernate-validator:pom:5.4.1.Final from/to wisdom-public (http://192.168.1.95:8081/repository/wisdom-test67/): Failed to transfer file: http://192.168.1.95:8081/repository/wisdom-test67/org/hibernate/validator/hibernate-validator/5.4.1.Final/hibernate-validator-5.4.1.Final.pom. Return code is: 400 , ReasonPhrase:Repository version policy: SNAPSHOT does not allow version: 5.4.1.Final. -> [Help 1]
[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] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
同上的原因。
2
[WARNING] Found duplicate and different resources in [org.springframework.data:spring-data-commons:1.13.17.RELEASE, org.springframework.data:spring-data-keyvalue:1.2.17.RELEASE, org.springframework.data:spring-data-redis:1.8.17.RELEASE]:
[WARNING] changelog.txt
...
[WARNING] Found duplicate classes/resources in test classpath.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 14.474 s
[INFO] Finished at: 2019-02-22T15:19:00+08:00
[INFO] Final Memory: 44M/418M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.basepom.maven:duplicate-finder-maven-plugin:1.2.1:check (duplicate-dependencies) on project mint: Found duplicate classes/resources! -> [Help 1]
一个changelog.txt 竟然引起了duplicate classes/resources问题，而且导致了编译错误。没有办法，只有把 相关的重复的jar 依赖去掉。去掉就好了。
经过仔细查找，发现 spring-boot-starters-1.5.18 依赖了duplicate-finder-maven-plugin：
C:\Users\rx63\.m2\repository\org\springframework\boot\spring-boot-starters\1.5.18.RELEASE\spring-boot-starters-1.5.18.RELEASE.pom
<plugin>
<groupId>org.basepom.maven</groupId>
<artifactId>duplicate-finder-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<id>duplicate-dependencies</id>
<phase>validate</phase>
<goals>
<goal>check</goal>
</goals>
<configuration>
<failBuildInCaseOfConflict>true</failBuildInCaseOfConflict>
</configuration>
</execution>
</executions>
</plugin>
3
还遇到各种神奇问题，format 也有问题。
[ERROR] Failed to execute goal io.spring.javaformat:spring-javaformat-maven-plugin:0.0.6:validate (default) on project wisteria-api: Formatting violations found in the following files:
[ERROR] * F:\dev\SVN\code\wisteria\wisteria-api\src\main\java\com\wisdom\wisteria\constants\search\TradeSearch.java
[ERROR] * F:\dev\SVN\code\wisteria\wisteria-api\src\main\java\com\wisdom\wisteria\trade\service\AccountTradeService.java
[ERROR]
[ERROR] Run `spring-javaformat:apply` to fix.
[ERROR] -> [Help 1]
经过仔细查找，发现spring-boot-parent-1.5.18 依赖了spring-javaformat-maven-plugin：
C:/Users/rx63/.m2/repository/org/springframework/boot/spring-boot-parent/1.5.18.RELEASE/spring-boot-parent-1.5.18.RELEASE.pom
<plugin>
<groupId>io.spring.javaformat</groupId>
<artifactId>spring-javaformat-maven-plugin</artifactId>
<version>${spring-javaformat.version}</version>
<executions>
<execution>
<phase>validate</phase>
<configuration>
<skip>${disable.checks}</skip>
</configuration>
<goals>
<goal>validate</goal>
</goals>
</execution>
</executions>
</plugin>
按照提示，执行下面的 命令 就好了：
mvn spring-javaformat:apply
javaformat这个插件真是烦人，只能接受tab作为缩进，4个空格等是不能通过validate的（我尝试通过IDEA对代码进行reformat，结果，这样的代码竟然都不能通过），
后面又做了对比，发现 spring-boot-1.5.18 这个版本真是奇葩，只有它是有duplicate-finder、 spring-javaformat 这些功能，其他的版本都没有的！！
4
[INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-rules) @ cactus-provider ---
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.BannedDependencies failed with message:
Found Banned Dependency: commons-logging:commons-logging:jar:1.1.1
Use 'mvn dependency:tree' to locate the source of the banned dependencies.
[WARNING] Found duplicate (but equal) classes in [org.apache.tomcat.embed:tomcat-embed-core:8.5.35, org.apache.tomcat:tomcat-juli:8.5.35]:
commons-logging:commons-logging:jar:1.1.1 被Banned 了 ？？ 不是很好理解，暂时把commons-logging 依赖去掉吧， 纳入exclusion 之后就好了！