api重复引用导致的诡异问题排查
最近一个项目上线前开发环境、测试环境都能正常打包并运行。然而到了准生产环境和生产环境则报一些诡异的错误信息：
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (default-compile) on project xxx: Compilation failure: Compilation failure:
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/util/ZipRsaCiph.java:[19,15] BASE64Decoder is internal proprietary API and may be removed in a future release
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/util/ZipRsaCiph.java:[19,15] BASE64Decoder is internal proprietary API and may be removed in a future release
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/util/ZipRsaCiph.java:[19,15] BASE64Decoder is internal proprietary API and may be removed in a future release
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/util/ZipRsaCiph.java:[19,15] BASE64Decoder is internal proprietary API and may be removed in a future release
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/util/ZipRsaCiph.java:[64,9] BASE64Decoder is internal proprietary API and may be removed in a future release
[ERROR] /data/release/xxx/xxx/src/main/java/com/xxx/testmodel/aop/Author.java:[95,90] error: cannot find symbol
[ERROR] -> [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/MojoFailureException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command咋一看莫名其妙，代码怎么找也找不到问题所在。查看代码修改部分，发现是重新引入了一个新的api。
通过mvn dependency:tree发现，同时引用了 test-api:jar:2.0.0 和 test-api:jar:3.12.0 两个版本的api。
而通过mvn dependency:analyze查看的结果为：
[WARNING] Used undeclared dependencies found:
[WARNING] com.xxx.auth:xxx-api:jar:2.0.0:compile
[WARNING] Unused declared dependencies found:
[WARNING] com.xxx.auth:xxx-api:jar:3.12.0:compile发现并没有引用新的api。Used undeclared dependencies ：指那些在项目中直接使用到的，但没有在POM中配置的依赖。Unused declared dependencies ：供我们参考，这表示那些我们配置了，但并未直接使用的依赖。
后来分析发现是有个第三方 api 引用了相同的api，从而导致这一诡异问题的出现。因而在引用api前可通过：
mvn dependency:tree 和 mvn dependency:analyze 看是否存在重复引用的api，如果存在重复引用的情况可将不需要的版本api排除掉即可。
<dependency>
<groupId>xxx</groupId>
<artifactId>xxx-api</artifactId>
<version>1.0</version>
<exclusions>
<exclusion>
<groupId>test</groupId>
<artifactId>test-api</artifactId>
</exclusion>
</exclusions>
</dependency>