如何在Log4J2中正确地使用AppenderComponentBuilder创建RollingFileAppender

Question

我希望用户选择将通过可配置选项创建的追加器的类型。

// simplified version of a method that creates and returns a logger
// using AppenderComponentBuilder
static Logger createLogger()
{
        ConfigurationBuilder< BuiltConfiguration > builder =
                ConfigurationBuilderFactory.newConfigurationBuilder();

        builder.setStatusLevel( Level.OFF );

        // create the syslog appender
        AppenderComponentBuilder appenderBuilder =
                builder.newAppender( "syslogAppender", "Syslog" )
                .addAttribute( "protocol", "TCP" )
                .addAttribute( "host", "localhost" )
                .addAttribute( "port", 514 )
                .addAttribute( "facility", "LOCAL2" )
                .addAttribute( "immediateFlush", true )
                .addAttribute( "newLine", true );
        builder.add( appenderBuilder );

        // create the new logger
        builder.add( builder.newLogger( "TestLogger", Level.DEBUG )
                .add( builder.newAppenderRef( "syslogAppender" ) )
                .addAttribute( "additivity", false ) );

        builder.add( builder.newRootLogger( Level.DEBUG )
                .add( builder.newAppenderRef( "syslogAppender" ) ) );

        // Initialize the new configuration
        LoggerContext ctx = Configurator.initialize( builder.build() );
        Logger logger = ctx.getLogger( "TestLogger" );
        return logger;
}

我的问题：

1）您认为这是使用Log4J2 API以编程方式创建记录器和系统日志追加器的最佳方式吗？

2）我想扩展上面的createLogger（）方法，以便它将根据用户的选择创建适当的追加器:file、syslog，两者都是。“file”选项应该创建一个具有特定模式布局、触发策略和滚动策略的滚动文件追加器。我尝试使用相同的Log4J2 API并使用AppenderComponentBuilder来完成此操作，但我找不到正确的方法。我设法以编程方式做到这一点的唯一方法是使用rollingFileAppender.createAppender（）方法，这是一个非常麻烦的问题，使我很难以编程方式动态创建一个带有滚动文件追加器、syslog追加器或两者（取决于用户输入）的记录器。

提前致谢

Answer 1

>

是的，这是以编程方式创建新配置的预期方法。

下面是一个如何创建滚动文件追加器的示例。由于可以用任意组件配置追加器，因此可以使用通用ComponentBuilder来指定这些插件。

ConfigurationBuilder< BuiltConfiguration > builder =
        ConfigurationBuilderFactory.newConfigurationBuilder();

builder.setStatusLevel( Level.ERROR);
builder.setConfigurationName("RollingBuilder");
// create the console appender
AppenderComponentBuilder appenderBuilder = builder.newAppender("Stdout", "CONSOLE").addAttribute("target",
        ConsoleAppender.Target.SYSTEM_OUT);
appenderBuilder.add(builder.newLayout("PatternLayout").
        addAttribute("pattern", "%d [%t] %-5level: %msg%n%throwable"));
builder.add( appenderBuilder );

LayoutComponentBuilder layoutBuilder = builder.newLayout("PatternLayout")
        .addAttribute("pattern", "%d [%t] %-5level: %msg%n");
ComponentBuilder triggeringPolicy = builder.newComponent("Policies")
        .addComponent(builder.newComponent("CronTriggeringPolicy").addAttribute("schedule", "0 0 0 * * ?"))
        .addComponent(builder.newComponent("SizeBasedTriggeringPolicy").addAttribute("size", "100M"));
appenderBuilder = builder.newAppender("rolling", "RollingFile")
        .addAttribute("fileName", "target/rolling.log")
        .addAttribute("filePattern", "target/archive/rolling-%d{MM-dd-yy}.log.gz")
        .add(layoutBuilder)
        .addComponent(triggeringPolicy);
builder.add(appenderBuilder);

// create the new logger
builder.add( builder.newLogger( "TestLogger", Level.DEBUG )
        .add( builder.newAppenderRef( "rolling" ) )
        .addAttribute( "additivity", false ) );

builder.add( builder.newRootLogger( Level.DEBUG )
        .add( builder.newAppenderRef( "rolling" ) ) );
Configurator.initialize(builder.build());