Log4jLoggerFactory.java 文件源码

public static Logger getLogger(String name, LoggerFactory loggerFactory) {
    org.apache.log4j.Logger instance = log4jLoggers.get(name);
    if (instance != null) {
        return instance;
    } else {
        Logger newInstance = loggerFactory.makeNewLoggerInstance(name);
        Logger oldInstance = log4jLoggers.putIfAbsent(name, newInstance);
        return oldInstance == null ? newInstance : oldInstance;
    }
}