Spring Boot之mvnw的启动错误Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain
引言： 偶尔在Spring Boot的使用过程中，你会碰到这样的错误，于是满世界的找问题，有时候其实你想错了，不是maven的错，而是spring boot本身的某些设置才会有，本文将解决这个错误。
1. 错误信息
在下载了一个spring boot项目之后，将要运行启动项目之时，发现启动不了，报出如下错误信息：
[root@flybird WXDemo]# ./mvnw
Error: Could not find or load main class org.apache.maven.wrapper.MavenWrapperMain首先是按照mvn设置本身的问题方向来分析，M2_HOME, PATH等各种环境变量一通查，没有发现问题。于是切换了maven的版本，还是没有能够解决问题，于是网络一通四处搜索，但是都是说，应该是环境变量配错导致的问题，其实，我总觉得不应该是这个原因，因为mvn可以正常工作。
于是换个思路，是不是spring boot的某些内容带给了maven的设置修改，顺着这个思路查，万能的google帮忙我们找到了答案，缺少了某些配置信息和jar包。
3. 解决问题
网上的指令说使用： mvn –N io.takari:maven:wrapper
mvn –N io.takari:maven:wrapper
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building WXDemo 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Skipping WXDemo
[INFO] This project has been banned from the build due to previous failures.
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.909 s
[INFO] Finished at: 2016-08-11T18:43:48+08:00
[INFO] Final Memory: 8M/29M
[INFO] ------------------------------------------------------------------------
[ERROR] Unknown lifecycle phase "–N". You must specify a valid lifecycle phase or a goal in the format : or :[:]:. Available lifecycle phases are: validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy, pre-clean, clean, post-clean, pre-site, site, post-site, site-deploy. -> [Help 1]
[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/confluence/display/MAVEN/LifecyclePhaseNotFoundException 执行新的命令： mvn io.takari:maven:wrapper
[root@test WXDemo]# mvn io.takari:maven:wrapper
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building WXDemo 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven:0.3.3:wrapper (default-cli) @ meal ---
[INFO]
[INFO] The Maven Wrapper has been successfully setup for your project.
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.693 s
[INFO] Finished at: 2016-08-11T18:45:51+08:00
[INFO] Final Memory: 9M/29M
[INFO] ------------------------------------------------------------------------ 执行指令： ./mvnw
[root@test WXDemo]# ./mvnw
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.812 s
[INFO] Finished at: 2016-08-11T18:46:33+08:00
[INFO] Final Memory: 8M/29M
[INFO] ------------------------------------------------------------------------
[ERROR] No goals have been specified for this build. You must specify a valid lifecycle phase or a goal in the format : or :[:]:. Available lifecycle phases are: validate, initialize, generate-sources, process-sources, generate-resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources, test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install, deploy, pre-clean, clean, post-clean, pre-site, site, post-site, site-deploy. -> [Help 1]
[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/confluence/display/MAVEN/NoGoalSpecifiedException 5. mvn的版本
在官方给出的文档中的-N参数不支持的问题，可以归结为mvn版本之间的变化以及迁移。此测试中出现的mvn版本信息如下：
[root@flybird WXMeal]# mvn -version
Apache Maven 3.3.3 (7994120775791599e205a5524ec3e0dfe41d4a06; 2015-04-22T19:57:37+08:00)
Maven home: /opt/maven
Java version: 1.8.0_91, vendor: Oracle Corporation
Java home: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.91-0.b14.el7_2.x86_64/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "3.10.0-327.3.1.el7.x86_64", arch: "amd64", family: "unix"