Log4j2で全設定をコードで行う方法

Log4j2で設定ファイルを使用せずにコードで設定を行う方法のメモ

サンプルソース

ConsoleAppenderとRollingFileAppenderを使用した例

sample.java

// ログ出力パターン
// 例) 2016-10-05 11:30:53.749  INFO   Hello world
private static final String LOG_PATTERN = "%d{yyy-MM-dd HH:mm:ss.SSS}  %-5level %logger{0} %msg%n";

// ログファイル名
private static final String LOG_NAME = "sample.log";

// ローテーション後のログファイル命名パターン
private static final String LOG_NAME_PATTERN = "sample_%i.log";

// ConsoleAppender名
private static final String CONSOLE_APPENDER_NAME = "CONSOLE_APPENDER";

// RollingFileAppender名
private static final String ROLLING_APPENDER_NAME = "FILE_APPERNDER";

// ログファイル最大サイズ
private static final String LOG_FILE_SIZE = "10MB";

// ログファイル世代管理数
private static final String LOG_ROLLOVER_STRATEGY = "10";

// ログレベル
private static final Level LOG_LEVEL = Level.INFO;

/**
 * ロガー生成
 **/
private static Logger getLogger() {

    try {
        String logDir = "logs" +  File.separator;

        // create LoggerContext
        LoggerContext context = (LoggerContext) LogManager.getContext(false);
        Configuration config = context.getConfiguration();
        PatternLayout layout = PatternLayout.createLayout(
                LOG_PATTERN, 
                null, 
                null, 
                Charset.defaultCharset(), 
                false,
                false, 
                null, 
                null);

        SizeBasedTriggeringPolicy policy = SizeBasedTriggeringPolicy.createPolicy(LOG_FILE_SIZE);
        DefaultRolloverStrategy strategy = DefaultRolloverStrategy.createStrategy(
                LOG_ROLLOVER_STRATEGY, 
                "0", 
                null, 
                null, 
                config);

        RollingFileManager fileManager = RollingFileManager.getFileManager(
                logDir + LOG_NAME,
                logDir + LOG_NAME_PATTERN,
                false,
                false,
                policy,
                strategy,
                null,
                layout,
                128);
        policy.initialize(fileManager);

        // create Appenders
        Appender rollingAppender = RollingFileAppender.createAppender(
                logDir + LOG_NAME,
                logDir + LOG_NAME_PATTERN,
                "false",
                ROLLING_APPENDER_NAME,
                "false",
                "128",
                "true",
                policy,
                strategy,
                layout,
                (Filter) null,
                "false",
                "false",
                (String) null,
                config);
        rollingAppender.start();

        Appender consoleAppender = ConsoleAppender.createAppender(
                layout,
                null,
                null,
                CONSOLE_APPENDER_NAME,
                null,
                null);
        consoleAppender.start();

        // Appender ref
        AppenderRef ref = AppenderRef.createAppenderRef(CONSOLE_APPENDER_NAME, LOG_LEVEL, null);
        AppenderRef ref2 = AppenderRef.createAppenderRef(ROLLING_APPENDER_NAME, LOG_LEVEL, null);
        AppenderRef[] refs = new AppenderRef[] { ref, ref2 };

        // LoggerConfig
        LoggerConfig loggerConfig = LoggerConfig.createLogger(
                "true",
                LOG_LEVEL,
                LogManager.ROOT_LOGGER_NAME,
                "true",
                refs,
                null,
                config,
                null);
        loggerConfig.addAppender(rollingAppender, LOG_LEVEL, null);
        loggerConfig.addAppender(consoleAppender, LOG_LEVEL, null);

        config.addLogger(LogManager.ROOT_LOGGER_NAME, loggerConfig);
        context.updateLoggers(config);

    } catch (Exception e) {
        System.out.println(e);

    }
    return LogManager.getLogger(LogManager.ROOT_LOGGER_NAME);
}

XMLだとこんな感じ

lo4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="error">

    <!-- Properties -->
    <Properties>
        <Property name="pattern">%d{yyy-MM-dd HH:mm:ss.SSS}  %-5level %logger{0} %msg%n</Property>
    </Properties>

    <!-- Console Appender -->
    <Appenders>
        <Console name="CONSOLE_APPENDER" target="SYSTEM_OUT">
            <PatternLayout pattern="${pattern}" />
        </Console>

        <!-- Rolling File Appender -->
        <RollingFile name="FILE_APPERNDER"
            fileName="logs/sample.log"
            filePattern="logs/sample_%i.log">
            <PatternLayout pattern="${pattern}" />
            <Policies>
                <SizeBasedTriggeringPolicy size="10MB" />
                <TimeBasedTriggeringPolicy />
            </Policies>
            <DefaultRolloverStrategy max="10" />
        </RollingFile>
    </Appenders>

    <Loggers>
        <Root level="info">
            <AppenderRef ref="CONSOLE_APPENDER" />
            <AppenderRef ref="FILE_APPERNDER" />
        </Root>
    </Loggers>
</Configuration>