通过全局配置文件配置记录器 [英] configure Logger via global config file

问题描述

我想拥有1个配置文件，其中包含有关特定类中的记录器应该如何记录/如何记录/记录的信息.

I'd like to have 1 configuration file that contains information about how/where/what logger in particular class should log.

示例:

Foo类

package myApp;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.Logger;

class Foo {
    static final Logger logger = Logger.getLogger(Foo.class.getName());

    public static void main(String[] args) throws IOException {

        FileInputStream fis =  new FileInputStream("C:\\path\\to\\myApp.log.properties");
        LogManager.getLogManager(). readConfiguration(fis);

        logger.log(Level.INFO, "Msg message");

        Bar obj = new Bar();

        obj.doSth();
}

班级酒吧

package myApp;

import java.util.logging.Level;
import java.util.logging.Logger;

public class Bar {

    static final Logger logger = Logger.getLogger(Bar.class.getName());

    public Bar() {
    }

    public void doSth() {
        logger.log(Level.WARNING, "Msg message");
    }
}

文件myApp.log.properties

File myApp.log.properties

handlers = 
config   =

myApp.Foo.handlers           = java.util.logging.ConsoleHandler
myApp.Foo.useParentHandlers  = false
myApp.Foo.level              = INFO

myApp.Bar.handlers           = java.util.logging.ConsoleHandler
myApp.Bar.useParentHandlers  = false
myApp.Bar.level              = INFO

输出:

Jul 23, 2014 1:27:12 PM myApp.Bar doSth
WARNING: Msg message

如您所见，缺少Foo的日志记录，我想这是因为logger是静态的，并且是在加载和设置LogManager的配置之前创建的.

As you can see, the log record for Foo is missing, i guess it's because logger is static and is created before configuration for LogManager is loaded and set.

能否请您提出为Foo的记录器打印日志记录的解决方案?还使用静态记录器，并且在执行程序时使用命令行参数-D configFile 不使用吗?

Could you please suggest solution where log record is printed for Foo's logger? Also with a static logger and without using commandline parameter -D configFile when the program is executed?

推荐答案

在您的示例中，调用了LogingToFile.doSth而不是Bar.doSth.修改您的配置文件以包括:

In your example, LogingToFile.doSth is called instead of Bar.doSth. Modify your config file to include:

myApp.LogingToFile.handlers           = java.util.logging.ConsoleHandler
myApp.LogingToFile.useParentHandlers  = false
myApp.LogingToFile.level              = INFO

或将new Bar().doSth();添加到您的主要方法中.

Or add new Bar().doSth(); to your main method.

通读LogManager源代码，似乎仅在设置配置后创建记录器时才加载Handlers.这是错误 JDK-8033661 readConfiguration不会干净地重新初始化日志记录系统.列出的解决方法是:

Reading through the LogManager source code it appears that Handlers are only loaded when the logger is created after the configuration is set. This is bug JDK-8033661 readConfiguration does not cleanly reinitialize the logging system. The listed workarounds are:

• 请勿在日志配置文件中使用按记录程序处理程序
• 请勿调用readConfiguration()或readConfiguration(InputStream)，而是将配置存储在文件中并在JVM启动时将其加载
• 配置通过API调用的日志记录

• Do not use per-logger handlers in your log configuration file
• Do not call readConfiguration() or readConfiguration(InputStream), but store the configuration in a file and load it on JVM startup
• Configure your logging through API calls

鉴于您的限制，解决方法是在创建记录器之前先加载配置.

Given your constraints, the workaround will be to load the configuration before creating the loggers.

class Foo {

    static {
        try (FileInputStream fis = new FileInputStream("C:\\path\\to\\myApp.log.properties")) {
            LogManager.getLogManager().readConfiguration(fis);
        } catch (IOException ex) {
            throw new ExceptionInInitializerError(ex);
        }
    }

    static final Logger logger = Logger.getLogger(Foo.class.getName());

    public static void main(String[] args) throws IOException {
        logger.log(Level.INFO, "Msg message");

        Bar obj = new Bar();

        obj.doSth();
    }
}

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