多个classloader加载log4j时需要设置当前Thread的classloader为你自己的classloader
Thread.currentThread().setContextClassLoader(classLoader); //for log4j
摘自：org.apache.log4j.helpers.Loader
/** * If running under JDK 1.2 load the specified class using the * <code>Thread</code> <code>contextClassLoader</code> if that * fails try Class.forname. Under JDK 1.1 only Class.forName is * used. * */ static public Class loadClass (String clazz) throws ClassNotFoundException { // Just call Class.forName(clazz) if we are running under JDK 1.1 // or if we are instructed to ignore the TCL. if(java1 || ignoreTCL) { return Class.forName(clazz); } else { try { return getTCL().loadClass(clazz); } catch(Throwable e) { // we reached here because tcl was null or because of a // security exception, or because clazz could not be loaded... // In any case we now try one more time return Class.forName(clazz); } }
log4j:ERROR A "org.apache.log4j.DailyRollingFileAppender" object is not assignable to a "org.apache.log4j.Appender" variable. log4j:ERROR The class "org.apache.log4j.Appender" was loaded by log4j:ERROR [com.generallycloud.baseio.container.URLDynamicClassLoader@55740540] whereas object of type log4j:ERROR "org.apache.log4j.DailyRollingFileAppender" was loaded by [sun.misc.Launcher$AppClassLoader@18b4aac2]. log4j:ERROR Could not instantiate appender named "main". log4j:ERROR A "org.apache.log4j.ConsoleAppender" object is not assignable to a "org.apache.log4j.Appender" variable. log4j:ERROR The class "org.apache.log4j.Appender" was loaded by log4j:ERROR [com.generallycloud.baseio.container.URLDynamicClassLoader@55740540] whereas object of type log4j:ERROR "org.apache.log4j.ConsoleAppender" was loaded by [sun.misc.Launcher$AppClassLoader@18b4aac2]. log4j:ERROR Could not instantiate appender named "console". log4j:WARN No appenders could be found for logger (com.generallycloud.baseio.component.ssl.SSLUtil). log4j:WARN Please initialize the log4j system properly.