Java Logging: Formatters

最新推荐文章于 2024-07-29 18:11:16 发布

转载最新推荐文章于 2024-07-29 18:11:16 发布 · 136 阅读

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原文链接：http://www.cnblogs.com/hephec/p/4579625.html

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#java

本文介绍如何在Java中使用日志记录器，包括内置的SimpleFormatter和XMLFormatter，以及如何创建和使用自定义日志记录器。通过提供一个简单的示例，解释了如何覆盖Formatter类的方法来定制日志输出格式，并讨论了自定义日志格式的潜在应用场景。

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The Handler's in the Java Logging API use a java.util.logging.Formatter to format theLogRecord's before writing it to an external system.

Java comes with two built-in Formatter's (subclasses of Formatter):

SimpleFormatter
XMLFormatter

The various Handler's in the Java Logging API use either of these two Formatter's by default, but you can also set your own custom Formatter subclass on a Handler.

You can create your own Formatter by subclassing the java.util.logging.Formatter class. Here is a simple example:

public class MyFormatter extends Formatter {

    @Override
    public String format(LogRecord record) {
        return record.getLevel() + ":" + record.getMessage();
    }
}

The subclass must override the abstract format() method in the Formatter class. The String returned by theformat() is what is forwarded to the external system by the Handler. Exactly how the string should be formatted is up to you.

The Formatter class also contains the convenience method formatMessage() which can be used to format the message using the ResourceBundle of the LogRecord. Here is an example:

public class MyFormatter extends Formatter {

    @Override
    public String format(LogRecord record) {
        return formatMessage(record);
    }
}

You will not often need to implement your own Formatter, but once in a while, if a specific log format is required, a custom Formatter may be useful.

转载于:https://www.cnblogs.com/hephec/p/4579625.html