配置文件的路径在.../jenkins/config.xml (线上路径是/usr/local/tomcat7/webapps/jenkins/config.xml)
修复办法：千万注意：修复前一定要提前备份config.xml文件
然后需要删除config.xml文件中的以下内容：
<useSecurity>true</useSecurity>
<authorizationStrategy class="hudson.security.ProjectMatrixAuthorizationStrategy">
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:dongjicheng</permission>
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:huanghuaicheng</permission>
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:limeng</permission>
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:liuxianpeng</permission>
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:shaoxiaogang</permission>
<permission>com.cloudbees.plugins.credentials.CredentialsProvider.View:tangyi</permission>
<permission>hudson.model.Hudson.Administer:admin</permission>
<permission>hudson.model.Hudson.Read:dongjicheng</permission>
<permission>hudson.model.Hudson.Read:huanghuaicheng</permission>
<permission>hudson.model.Hudson.Read:limeng</permission>
<permission>hudson.model.Hudson.Read:liuxianpeng</permission>
<permission>hudson.model.Hudson.Read:shaoxiaogang</permission>
<permission>hudson.model.Hudson.Read:tangyi</permission>
<permission>hudson.model.Item.Build:dongjicheng</permission>
<permission>hudson.model.Item.Build:huanghuaicheng</permission>
<permission>hudson.model.Item.Build:limeng</permission>
<permission>hudson.model.Item.Build:liuxianpeng</permission>
<permission>hudson.model.Item.Build:shaoxiaogang</permission>
<permission>hudson.model.Item.Build:tangyi</permission>
</authorizationStrategy>
<securityRealm class="hudson.security.HudsonPrivateSecurityRealm">
<disableSignup>true</disableSignup>
<enableCaptcha>false</enableCaptcha>
</securityRealm>
然后重新启动jenkins，这样就不需要login登陆，直接就可以进入jenkins界面了，就跟jenkins刚搭建好首次打开的状态一样。
进入系统管理-全局安全配置，设置完后保存。
进入系统管理-管理用户，可以直接重置admin登陆密码。