1、 Packaging type of the project

jar

Default packaging format

war

Packaged into projects to be deployed

pom

The parent type is POM type

2、 POM

Simply put, a multi module project is defined by a parent POM referencing one or more sub modules.

3、 Finally

The main reason why this record should be made is that they are not familiar with the whole life cycle of Maven and are unfamiliar with multi modular project operations.

The conclusion is that if there are many project modules, you must pay attention to all the contents when building the project, including project name, hierarchical package name,

pom. XML file configuration; Because the hierarchical module, package name, dependent import and dependent scope of action will cause the project to fail to start!!!