XXX could not be redeployed because it could not be completely removed in the undeployment phase .

发布项目的时候Myeclipse弹出一个错误：

    XXX could not be redeployed because it could not be completely removed in the undeployment phase. the most common cuase of this problem is attempting to redeploy while the server is running,which has locked one or
more files.

把项目中引用的jar文件重新加一遍就行了，基本原因就是以前的jar文件不存在了，但是项目信息中还有，即项目的.classpath文件中还有不存在的jar文件引用。

可以右键点项目名称，选择Properties,选择Java Build Path,选择Libraries,把所有项目中的jar都remove，然后再点"add jars"，把项目中的jar文件都加进来，再次部署就正常了。

大不了删除项目，重新创建项目，再把想要jar包加进来，然后重新部署项目，启动，绝对能搞定！