maven无法启动tomcat，报错

Question

[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for cn.itcast:travel:war:1.0-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 121, column 21
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.141 s
[INFO] Finished at: 2020-10-30T19:54:41+08:00
[INFO] Final Memory: 6M/116M
[INFO] ------------------------------------------------------------------------

[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/confl...

Some problems were encountered while building the effective model for cn.itcast:travel:war:1.0-SNAPSHOT
'build.plugins.plugin.version' for org.apache.maven.plugins:maven-compiler-plugin is missing. @ line 121, column 21
It is highly recommended to fix these problems because they threaten the stability of your build.
For this reason, future Maven versions might no longer support building such malformed projects.

Answer 1

在构建cn.itcast:travel:war:1.0-SNAPSHOT时出现了一些问题。
org.apache.maven.plugins:maven-compiler-plugin插件未定义版本号。错误发生在121行，21列。
强烈的建议你修复这个问题，因为它会导致应用不稳定；这也是我们将在未来的maven版本中取消对此奇葩设置支持的原因。

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请确认是否没有为插件指定版本号，如果没有，请指定。