记录级别

Java Logging Api 有 7 个级别 。降序的级别为：

• SEVERE（最高价值）
• WARNING
• INFO
• CONFIG
• FINE
• FINER
• FINEST（最低价值）

默认级别为 INFO（但这取决于系统并使用虚拟机）。

注意 ：还有 OFF（可用于关闭注销）和 ALL（OFF 的对位）。

代码示例：

import java.util.logging.Logger;

public class Levels {
    private static final Logger logger = Logger.getLogger(Levels.class.getName());

    public static void main(String[] args) {

        logger.severe("Message logged by SEVERE");
        logger.warning("Message logged by WARNING");
        logger.info("Message logged by INFO");
        logger.config("Message logged by CONFIG");
        logger.fine("Message logged by FINE");
        logger.finer("Message logged by FINER");
        logger.finest("Message logged by FINEST");

        // All of above methods are really just shortcut for
        // public void log(Level level, String msg):
        logger.log(Level.FINEST, "Message logged by FINEST");
    }
}

默认情况下，运行此类将仅输出级别高于 CONFIG 的消息：

Jul 23, 2016 9:16:11 PM LevelsExample main
SEVERE: Message logged by SEVERE
Jul 23, 2016 9:16:11 PM LevelsExample main
WARNING: Message logged by WARNING
Jul 23, 2016 9:16:11 PM LevelsExample main
INFO: Message logged by INFO