java 模块化 与 maven java模块化开发

本节视频

概述

在多人协同开发时，特别是规模较大的项目，为了方便日后的代码维护和管理，我们会将每个开发人员的工作细分到具体的功能和模块上。随着项目的不断扩大，模块也会越来越多，后续会更加难以维护和扩展，为了应对这种情况后期我们还会采用微服务架构的方式进行开发。

以当前教程为例，我们可以将模块划分为如下形式：

统一的依赖管理(dependencies)

通用的工具类(commons)

领域模型(domain)

管理后台(admin)

商城前端(ui)

接口模块(api)

整个模块化开发过程主要是在开发思想上稍作了一些转变，只需要按照下面的流程操作即可。

创建根项目(工程)

创建一个名为 my-shop 的工程，pom.xml 文件如下：

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop
1.0.0-SNAPSHOT
pom

该项目称之为 Root 项目，主要作用是管理整个工程的全部模块，当有新模块加入时需要在 modules 元素下配置对应的模块目录

创建统一的依赖管理

创建一个名为 my-shop-dependencies 的项目，pom.xml 文件如下：

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop
1.0.0-SNAPSHOT
../pom.xml
my-shop-dependencies
pom
my-shop-dependencies
UTF-8
UTF-8
1.8
3.5
1.2
1.2.17
3.1.0
1.7.25
4.3.17.RELEASE
org.springframework
spring-context
${spring.version}
org.springframework
spring-webmvc
${spring.version}
javax.servlet
javax.servlet-api
${servlet-api.version}
provided
javax.servlet
jstl
${jstl.version}
org.slf4j
slf4j-api
${slf4j.version}
org.slf4j
slf4j-log4j12
${slf4j.version}
org.slf4j
jcl-over-slf4j
${slf4j.version}
org.slf4j
jul-to-slf4j
${slf4j.version}
log4j
log4j
${log4j.version}
org.apache.commons
commons-lang3
${commons-lang3.version}
org.apache.maven.plugins
maven-compiler-plugin
3.7.0
${java.version}
${java.version}
${project.build.sourceEncoding}
true
src/main/java
**/*.java
src/main/resources
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-dependencies 配置
创建通用的工具类
创建一个名为 my-shop-commons 的项目，pom.xml 文件如下：
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop-dependencies
1.0.0-SNAPSHOT
../my-shop-dependencies/pom.xml
my-shop-commons
jar
my-shop-commons
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-commons 配置
创建领域模型
创建一个名为 my-shop-domain 的项目，pom.xml 文件如下：
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop-dependencies
1.0.0-SNAPSHOT
../my-shop-dependencies/pom.xml
my-shop-domain
jar
my-shop-domain
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-domain 配置
创建管理后台
创建一个名为 my-shop-web-admin 的项目，pom.xml 文件如下：
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop-dependencies
1.0.0-SNAPSHOT
../my-shop-dependencies/pom.xml
my-shop-web-admin
war
my-shop-web-admin
com.funtl
my-shop-commons
${project.parent.version}
com.funtl
my-shop-domain
${project.parent.version}
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-web-admin 配置
创建商城前端
创建一个名为 my-shop-web-ui 的项目，pom.xml 文件如下：
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop-dependencies
1.0.0-SNAPSHOT
../my-shop-dependencies/pom.xml
my-shop-web-ui
war
my-shop-web-ui
com.funtl
my-shop-commons
${project.parent.version}
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-web-ui 配置
创建接口模块
创建一个名为 my-shop-web-api 的项目，pom.xml 文件如下：
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop-dependencies
1.0.0-SNAPSHOT
../my-shop-dependencies/pom.xml
my-shop-web-api
war
my-shop-web-api
com.funtl
my-shop-commons
${project.parent.version}
PS：别忘记在 my-shop 工程的 pom.xml 中增加 my-shop-web-api 配置
清理、编译、打包
至此一个完整的模块化工程创建完毕，此时的 Root 工程 pom.xml 文件如下：
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
com.funtl
my-shop
1.0.0-SNAPSHOT
pom
my-shop-dependencies
my-shop-commons
my-shop-domain
my-shop-web-admin
my-shop-web-ui
my-shop-web-api
我们可以在 Root 工程中使用 Maven 提供的 mvn clean 命令测试一下效果，控制台输出如下：
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] my-shop
[INFO] my-shop-dependencies
[INFO] my-shop-commons
[INFO] my-shop-domain
[INFO] my-shop-web-admin
[INFO] my-shop-web-ui
[INFO] my-shop-web-api
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-dependencies 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-dependencies ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-commons 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-commons ---
[INFO] Deleting D:\Workspace\my-shop\my-shop-commons\target
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-domain 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-domain ---
[INFO] Deleting D:\Workspace\my-shop\my-shop-domain\target
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-web-admin 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-web-admin ---
[INFO] Deleting D:\Workspace\my-shop\my-shop-web-admin\target
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-web-ui 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-web-ui ---
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building my-shop-web-api 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ my-shop-web-api ---
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] my-shop ............................................ SUCCESS [ 0.158 s]
[INFO] my-shop-dependencies ............................... SUCCESS [ 0.004 s]
[INFO] my-shop-commons .................................... SUCCESS [ 0.020 s]
[INFO] my-shop-domain ..................................... SUCCESS [ 0.016 s]
[INFO] my-shop-web-admin .................................. SUCCESS [ 0.033 s]
[INFO] my-shop-web-ui ..................................... SUCCESS [ 0.012 s]
[INFO] my-shop-web-api .................................... SUCCESS [ 0.008 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.400 s
[INFO] Finished at: 2018-06-12T07:47:58+08:00
[INFO] Final Memory: 8M/241M
[INFO] ------------------------------------------------------------------------