如何在 log4j2 中以编程方式配置 SmtpAppender

Question

Following is the code, I am working on:

Purpose is to configure SmtpAppender programmatically. Along with the SmtpAppender, I also need to add RollingFileAppender as well as Console appender programmatically.

package vish;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.appender.SmtpAppender;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
import org.apache.logging.log4j.core.config.builder.api.LayoutComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.RootLoggerComponentBuilder;
import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;

public class SmtpAppenderBuilder {

  public static void main(String[] args) {

    String pattern = "%d{MM-dd@HH\\:mm\\:ss}%-4r %-5p [%t] %37c %3x - %m%n";
    ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newConfigurationBuilder();
    LayoutComponentBuilder layoutBuilder = builder.newLayout("PatternLayout").addAttribute("pattern", pattern);

    RootLoggerComponentBuilder rootLogger = builder.newRootLogger(Level.DEBUG);
    builder.setStatusLevel(Level.DEBUG);
    org.apache.logging.log4j.core.appender.SmtpAppender.Builder smtpBuilder = SmtpAppender.newBuilder();
    smtpBuilder.setName("emailAppender");
    smtpBuilder.setSmtpUsername("test1@gmail.com");
    smtpBuilder.setSmtpPassword("###YpSv1925");
    smtpBuilder.setSmtpProtocol("https");
    smtpBuilder.setSmtpHost("smtp.gmail.com");
    smtpBuilder.setBufferSize(512);
    smtpBuilder.setTo("test2@gmail.com");
    smtpBuilder.setSubject("testing");
  }
}

How should I add the smtpAppender to the configutation or the rootLogger?

Answer 1

You are mixing up two APIs:

• the ConfigurationBuilder API , which is the closest code equivalent of the configuration files. It only creates definitions of the actual logging components, the real ones are created when Configuration#initialize() is called on the configuration object. You can create the definition of an SMTPAppender like this:

   private Configuration createConfig() { ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newConfigurationBuilder()//.setStatusLevel(Level.DEBUG); LayoutComponentBuilder layoutBuilder = builder.newLayout("PatternLayout")//.addAttribute("pattern", "%d{MM-dd@HH\\:mm\\:ss}%-4r %-5p [%t] %37c %3x - %m%n"); AppenderComponentBuilder appenderBuilder = builder.newAppender("emailAppender", "SMTP")//.addAttribute("smtpUsername", "test1@gmail.com").addAttribute("smtpPassword", "###YpSv1925").addAttribute("smtpProtocol", "smtps").addAttribute("smtpHost", "smtp.gmail.com").addAttribute("to", "test2@gmail.com").addAttribute("subject", "testing").add(layoutBuilder); AppenderRefComponentBuilder appenderRefBuilder = builder.newAppenderRef("emailAppender"); RootLoggerComponentBuilder rootLoggerBuilder = builder.newRootLogger(Level.DEBUG)//.add(appenderRefBuilder); return builder.add(appenderBuilder)//.add(rootLoggerBuilder).build(); }

• the actual builders of Log4j 2.x components, which are called by reflection by Configuration#initialize using the definitions above. You can also use them directly:

   private static Configuration createConfig2() { return new AbstractConfiguration(null, ConfigurationSource.NULL_SOURCE) { @Override protected void doConfigure() { Layout<String> layout = PatternLayout.newBuilder()//.withPattern("%d{MM-dd@HH\\:mm\\:ss}%-4r %-5p [%t] %37c %3x - %m%n").withConfiguration(this).build(); Appender appender = SmtpAppender.newBuilder()//.setName("emailAppender").setSmtpUsername("test1@gmail.com").setSmtpPassword("###YpSv1925").setSmtpProtocol("smtps").setTo("test2@gmail.com").setSubject("testing").setLayout(layout).setConfiguration(this).build(); LoggerConfig rootLogger = getRootLogger(); rootLogger.setLevel(Level.DEBUG); rootLogger.addAppender(appender, null, null); } }; }

Both Configuration s are equivalent and you can apply them on the current context with:

Configurator.reconfigure(config);

However they will be lost upon Configurator.reconfigure() , unless you define your own ConfigurationFactory .