如果部署GAE时正在upload files时退出，下次部署时会报错
Another transaction by user is already in progress for this app and major version. That user can undo the transaction with appcfg.py's "rollback" command
找到eclipse中的GAE SDK目录
如：D:\eclipse\plugins\com.google.appengine.eclipse.sdkbundle.1.3.8_1.3.8.v201010161055\appengine-java-sdk-1.3.8\bin
执行命令
appcfg.cmd rollback 后面跟gae项目war所在目录
如 appcfg.cmd rollback D:/spring/eclipse_workspace/taobaoke/war
执行：
********************************************************
Warning: Future versions of the Dev App Server will require Java 1.6 or later. P
lease upgrade your JRE.
********************************************************
Reading application configuration data...
2010-11-15 9:34:23 com.google.apphosting.utils.config.AppEngineWebXmlReader read
AppEngineWebXml
信息: Successfully processed D:/spring/eclipse_workspace/taobaoke/war\WEB-INF/ap
pengine-web.xml
2010-11-15 9:34:23 com.google.apphosting.utils.config.AbstractConfigXmlReader re
adConfigXml
信息: Successfully processed D:/spring/eclipse_workspace/taobaoke/war\WEB-INF/we
b.xml
2010-11-15 9:34:23 com.google.apphosting.utils.config.AbstractConfigXmlReader re
adConfigXml
信息: Successfully processed D:/spring/eclipse_workspace/taobaoke/war\WEB-INF/cr
on.xml
Beginning server interaction for taokeapp...
0% Rolling back the update.
Success.
Cleaning up temporary files...