ubuntu12.04 tomcat7 无法启动，真的无法启动

java配置
 
 export JAVA_HOME=/opt/jdk1.7.0_40                                                                                                                  
 export JRE_HOME=$JAVA_HOME/jre
 export CLASSPATH=$JAVA_HOME/lib:$JRE_HOME/lib
bin/startup.sh 
Using CATALINA_BASE:   /home/xviubu/tomcat
Using CATALINA_HOME:   /home/xviubu/tomcat
Using CATALINA_TMPDIR: /home/xviubu/tomcat/temp
Using JRE_HOME:        /opt/jdk1.7.0_40/jre
Using CLASSPATH:      /home/xviubu/tomcat/bin/bootstrap.jar:/home/xviubu/tomcat/bin/tomcat-juli.jar没有错误输出，但是 ps aux | grep tomcat 没有进程
nmap localhost 没有8080端口，浏览器打不开bin/shutdown.sh
Using CATALINA_BASE:   /home/xviubu/tomcat
Using CATALINA_HOME:   /home/xviubu/tomcat
Using CATALINA_TMPDIR: /home/xviubu/tomcat/temp
Using JRE_HOME:        /opt/jdk1.7.0_40/jre
Using CLASSPATH:       /home/xviubu/tomcat/bin/bootstrap.jar:/home/xviubu/tomcat/bin/tomcat-juli.jar
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory
at org.apache.catalina.startup.Bootstrap.<clinit>(Bootstrap.java:60)
Caused by: java.lang.ClassNotFoundException: org.apache.juli.logging.LogFactory
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
我真的无法搞定了，昨天还好好的今天开机运行就不行了
深夜求助tomcatubuntu