Question

我已经创建了一个实例后，我在NoClassDefFoundError上收到org.apache.commons.logging.LogFactory个异常。我可以创建一个LogFactory对象并从中获取org.apache.commons.logging.Log的实例但是在创建类型为org.apache.axis.description.TypeDesc的对象时，当此类尝试时会抛出NoClassDefFoundError从org.apache.commons.logging.Log获取LogFactory的实例。似乎应该在第284行抛出异常。（？）

这是我的代码（DtUiLoggingRequest第282行到第294行）;

log.debug("vvvvvvvvvvvvvvvv");

org.apache.commons.logging.LogFactory logFactory = (org.apache.commons.logging.LogFactory)LogFactory.getFactory();
Log myLog = LogFactory.getLog(DtUiLoggingRequest.class.getName());

log.debug(logFactory.getClass().getName());
log.debug(myLog.getClass().getName());

myLog.debug("This is coming from 'myLog'");

log.debug("^^^^^^^^^^^^^^^^");

typeDesc = new org.apache.axis.description.TypeDesc(DtUiLoggingRequest.class);

这是日志所说的内容;

DEBUG   2012-02-23 09:32:08,739 vvvvvvvvvvvvvvvv  
DEBUG   2012-02-23 09:32:08,739 org.apache.commons.logging.impl.LogFactoryImpl  
DEBUG   2012-02-23 09:32:08,739 org.apache.commons.logging.impl.Log4JLogger  
DEBUG   2012-02-23 09:32:08,739 ^^^^^^^^^^^^^^^^  
ERROR   2012-02-23 09:32:08,739 Exception Details:  
java.lang.NoClassDefFoundError: org.apache.commons.logging.LogFactory  
    at org.apache.axis.components.logger.LogFactory.class$(LogFactory.java:45)  
    at org.apache.axis.components.logger.LogFactory$1.run(LogFactory.java:45)  
    at java.security.AccessController.doPrivileged(Native Method)  
    at org.apache.axis.components.logger.LogFactory.getLogFactory(LogFactory.java:41)  
    at org.apache.axis.components.logger.LogFactory.<clinit>(LogFactory.java:33)  
    at org.apache.axis.description.TypeDesc.<clinit>(TypeDesc.java:61)  
    at com.symantec.cas.ucf.sensors.DtUiLoggingRrequest.initTypeDesc(DtUiLoggingRequest.java:294)  
    at com.symantec.cas.ucf.sensors.sap.DtUiLoggingRequest.<init>(DtUiLoggingRequest.java:58)  
    at com.symantec.cas.ucf.sensors.sap.SapSensor.OpenDevice(Sensor.java:151)  
    at com.symantec.cas.ucf.collector.SensorJob.openSensor(SensorJob.java:156)  
    at com.symantec.cas.ucf.collector.SensorJob.run(SensorJob.java:290)  
    at java.lang.Thread.run(Thread.java:662)

Answer 1

这看起来像是一个类加载器问题。您正在使用具有分层类加载器的系统（如Web应用程序），并且Axis由比Commons Logging更高级别的类加载器加载。这意味着，即使Commons Logging在您的系统中，Axis也不允许看到它。我疯狂的猜测是你从一个JRE扩展目录加载Axis，但从你的war文件中加载Commons Logging。

即使在创建对象后，也会抛出NoClassDefFoundError

1 个答案: