在记录活动中使用readConfiguration方法

Question

为了在小型Java桌面应用程序中使用日志记录，我试图深入了解某些方法的操作。我使用一个非常愚蠢的小型Java程序对其进行测试。

特别是，在测试LogManager.readConfiguration（）方法的行为时，我发现了一些奇怪的东西。在所有测试中，LogManager均从JRE目录中lib
/ logging.properties中的属性文件中读取其配置。此时，此文件的内容如下：

handlers=java.util.logging.ConsoleHandler
myapp2.handlers=java.util.logging.ConsoleHandler
myapp2.MyApp2.handlers=java.util.logging.ConsoleHandler
.level=OFF
java.util.logging.ConsoleHandler.level=ALL
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
java.util.logging.SimpleFormatter.format=%4$s: %5$s [%1$tc]%n
myapp2.level=WARNING
myapp2.MyApp2.level=INFO

Java程序的代码是：

package myapp2;

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

public class MyApp2 {

    private static final Logger LOGGER = Logger.getLogger(MyApp2.class.getPackage().getName());
    private static final Logger LOGGER1 = Logger.getLogger(MyApp2.class.getName());

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        LOGGER.severe("severe at MyApp2");
        LOGGER.warning("warning at MyApp2");
        LOGGER.info("info at MyApp2");
        LOGGER1.severe("severe1 at MyApp2");
        LOGGER1.warning("warning1 at MyApp2");
        LOGGER1.info("info1 at MyApp2");
        LOGGER1.setLevel(null);
        LOGGER1.setUseParentHandlers(false);
        LOGGER1.severe("severe2 at MyApp2");
        LOGGER1.warning("warning2 at MyApp2");
        LOGGER1.info("info2 at MyApp2");
        try {
            LogManager.getLogManager().readConfiguration();
        } catch (IOException ex) {
            System.out.println("I/O Exception found");
        } catch (SecurityException ex) {
            System.out.println("Error SecurityException found");
        }
        LOGGER.severe("severe3 at MyApp2"); 
        LOGGER1.severe("severe4 at MyApp2");
    }
}

如果我们在没有围绕readConfiguration（）的try-catch的情况下执行它，则将按预期工作，并且输出如下：

SEVERE: severe at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe at MyApp2 [dc. maig 08 14:45:38 CEST 2013] 
WARNING: warning at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
WARNING: warning at MyApp2 [dc. maig 08 14:45:38 CEST 2013] 
SEVERE: severe1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe2 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
WARNING: warning2 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe3 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe3 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]
SEVERE: severe4 at MyApp2 [dc. maig 08 14:45:38 CEST 2013]

但是，如果我们使用try-catch执行，则输出为：

SEVERE: severe at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
INFO: info1 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe2 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
WARNING: warning2 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]
SEVERE: severe3 at MyApp2 [dc. maig 08 14:46:51 CEST 2013]

读取readConfiguration（）方法的API后，应该重新初始化日志记录属性，并从先前命名的文件中重新读取日志记录配置。如果是的话，为什么feature3仅显示一次（由于程序中存在两个LOGGER和转发行为，我预计将显示两次）而严重4缺失（我希望显示一次）？有人可以帮我理解这个吗？

Answer 1

我在使用readConfiguration方法时遇到了很多错误。它不是您期望的。我创建了一个小单元测试来说明这一点：

package com.demo;

import java.io.IOException;
import java.io.InputStream;
import java.util.logging.LogManager;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author dhubau
 */
public class LogTest {

    private static final Logger logger = LoggerFactory.getLogger(LogTest.class.getCanonicalName());

    @Test
    public void testLogs() throws IOException {
        logger.trace("BEFORE");
        logger.debug("BEFORE");
        logger.info("BEFORE");
        logger.warn("BEFORE");
        logger.error("BEFORE");

        InputStream is = LogTest.class.getResourceAsStream("/logging.properties");

        LogManager.getLogManager().readConfiguration(is);

        logger.trace("AFTER");
        logger.debug("AFTER");
        logger.info("AFTER");
        logger.warn("AFTER");
        logger.error("AFTER");
    }
}

启动单元测试时，将读取默认的logging.properties（将所有信息默认为INFO日志记录）。我记录每个级别一次，然后读取自己的logging.properties文件：

# Specify the handlers to create in the root logger
handlers = java.util.logging.ConsoleHandler

# Set the default logging level for the root logger
.level = INFO

# Do not use the root handlers
com.demo.useParentHandlers = false

# DEMO log handlers
com.demo.handlers = java.util.logging.ConsoleHandler

# DEMO log level
com.demo.level = ALL

# Set the default logging level for new ConsoleHandler instances
java.util.logging.ConsoleHandler.level = ALL

之后，我得到以下输出：

May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
INFO: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
WARNING: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
SEVERE: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
INFO: AFTER
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
WARNING: AFTER
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
SEVERE: AFTER

因此，您看到com.demo程序包未记录TRACE或DEBUG级别。当我将以下参数传递给单元测试时：

java.util.logging.config.file = C：\ TEMP \ logging.properties

它给了我以下输出：

May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
FINEST: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
FINE: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
INFO: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
WARNING: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
SEVERE: BEFORE
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
INFO: AFTER
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
WARNING: AFTER
May 24, 2013 11:27:29 AM com.demo.LogTest testLogs
SEVERE: AFTER