安装了MAVEN（寒假重做系统，eclipse无了重新用的idea）
解决了一个报错的小问题
maven运行报错代码
No goals have been specified for this build. You must specify a valid lifecycle phase or a goal in the format <plugin-prefix>:<goal> or <plugin-group-id>:<plugin-artifact-id>[:<plugin-version>]:<goal>. Available lifecycle phases are: validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources,
在pox.xml文件中的build标签中添加这一句话
<defaultGoal>compile</defaultGoal>（不明白干啥的 反正不报错了QAQ）
