org.apache.log4j.LogManager类有一个静态块,首先是找log4j.xml，找不到的情况下才找log4j.properties
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// if the user has not specified the log4j.configuration// property, we search first for the file "log4j.xml" and then// "log4j.properties"if (configurationOptionStr == null) {
url = Loader.getResource(DEFAULT_XML_CONFIGURATION_FILE);
if (url == null) {
url = Loader.getResource(DEFAULT_CONFIGURATION_FILE);
}
} else {
try {
url = new URL(configurationOptionStr);
} catch (MalformedURLException ex) {
// so, resource is not a URL:
// attempt to get the resource from the class path
url = Loader.getResource(configurationOptionStr);
}
} |
2，然后是怎么找呢：如下代码，是委托给classloader(加载Loader类的classloader)去找了，
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// We could not find resource. Ler us now try with the
// classloader that loaded this class.
classLoader = Loader.class.getClassLoader();
if(classLoader != null) {
LogLog.debug("Trying to find ["+resource+"] using "+classLoader
+" class loader.");
url = classLoader.getResource(resource);
if(url != null) {
return url;
}
}
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3，classloader的getResource(...)又是怎么找呢：总是先从父classloader里去找，找不到才自己去找
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public URL getResource(String name) {
URL url;
if (parent != null) {
url = parent.getResource(name);
} else {
url = getBootstrapResource(name);
}
if (url == null) {
url = findResource(name);
}
return url;
}
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