Maven 生命周期
Look：1036，By admin Posted On 2018-02-12
1、三套生命周期
对于maven的生命周期来说，共有三个相互独立的生命周期，分别是clean、default、site。clean生命周期目的是清理项目，default生命周期目的是构建项目，而site生命周期目的是建立项目站点。
每个生命周期分别包含一些阶段，这些阶段是有顺序的，并且后面的阶段依赖于前面的阶段。如clean生命周期包含pre-clean、clean和post-clean三个阶段，如果执行clean阶段，则会先执行pre-clean阶段。
较之于生命周期阶段有前后依赖关系，三套生命周期本身是相互独立的，用户可以仅调用clean生命周期的某个阶段，也可以不执行clean周期，而直接执行default生命周期的某几个阶段。
2、clean生命周期
clean生命周期包含三个阶段，主要负责清理项目，如下：
pre-clean |--executes processes needed prior to the actual project cleaning
clean |--remove all files generated by the previous build
post-clean |--executes processes needed to finalize the project cleaning
3、default生命周期
default生命周期定义了真正构建时所需要执行的所有步骤，包含的阶段如下：
validate validate the project is correct and all necessary information is available.
initialize initialize build state, e.g. set properties or create directories.
generate-sources generate any source code for inclusion in compilation.
process-sources process the source code, for example to filter any values.
generate-resources generate resources for inclusion in the package.
process-resources copy and process the resources into the destination directory, ready for packaging.
compile compile the source code of the project.
process-classes post-process the generated files from compilation, for example to do bytecode enhancement on Java classes.
generate-test-sources generate any test source code for inclusion in compilation.
process-test-sources process the test source code, for example to filter any values.
generate-test-resources create resources for testing.
process-test-resources copy and process the resources into the test destination directory.
test-compile compile the test source code into the test destination directory
process-test-classes post-process the generated files from test compilation, for example to do bytecode enhancement on Java classes. For Maven 2.0.5 and above.
test run tests using a suitable unit testing framework. These tests should not require the code be packaged or deployed.
prepare-package perform any operations necessary to prepare a package before the actual packaging. This often results in an unpacked, processed version of the package. (Maven 2.1 and above)
package take the compiled code and package it in its distributable format, such as a JAR.
pre-integration-test perform actions required before integration tests are executed. This may involve things such as setting up the required environment.
integration-test process and deploy the package if necessary into an environment where integration tests can be run.
post-integration-test perform actions required after integration tests have been executed. This may including cleaning up the environment.
verify run any checks to verify the package is valid and meets quality criteria.
install install the package into the local repository, for use as a dependency in other projects locally.
deploy done in an integration or release environment, copies the final package to the remote repository for sharing with other developers and projects.
4、site生命周期
siet生命周期的目的是建立和发布项目站点，maven能够基于POM所包含的信息，自动生成一个友好的站点，方便团队交流和发布项目信息，包含的阶段如下：
pre-site executes processes needed prior to the actual project site generation
site generates the project's site documentation
post-site executes processes needed to finalize the site generation, and to prepare for site deployment
site-deploy deploys the generated site documentation to the specified web server
5、命令行与生命周期
从命令行执行maven任务的最主要方式就是调用maven的生命周期阶段。需要注意的是，各个生命周期是相互独立的，而一个生命周期的阶段是有前后依赖关系的。例子如下：
1、$mvn clean ：该命令调用clean生命周期的clean阶段。实际执行的阶段为clean生命周期的pre-clean和clean阶段。
2、$mvn test：该命令调用default生命周期的test阶段。实际调用的是default生命周期的validate、initialize等，直到test的所有阶段。
3、$mvn clean install：该命令调换用clean生命周期的clean阶段和default生命周期的instal阶段。
