mybatis的日志工厂

LogFactory

private static void tryImplementation(Runnable runnable) {
    if (logConstructor == null) {
      try {
        runnable.run();
      } catch (Throwable t) {
        // ignore
      }
    }
  }

public static synchronized void useSlf4jLogging() {
    setImplementation(org.apache.ibatis.logging.slf4j.Slf4jImpl.class);
  }

  public static synchronized void useCommonsLogging() {
    setImplementation(org.apache.ibatis.logging.commons.JakartaCommonsLoggingImpl.class);
  }

  public static synchronized void useLog4JLogging() {
    setImplementation(org.apache.ibatis.logging.log4j.Log4jImpl.class);
  }

  public static synchronized void useLog4J2Logging() {
    setImplementation(org.apache.ibatis.logging.log4j2.Log4j2Impl.class);
  }

  public static synchronized void useJdkLogging() {
    setImplementation(org.apache.ibatis.logging.jdk14.Jdk14LoggingImpl.class);
  }

  public static synchronized void useStdOutLogging() {
    setImplementation(org.apache.ibatis.logging.stdout.StdOutImpl.class);
  }

  public static synchronized void useNoLogging() {
    setImplementation(org.apache.ibatis.logging.nologging.NoLoggingImpl.class);
  }

其中一个实现类

  public class Log4j2Impl implements Log {

  private final Log log;

  public Log4j2Impl(String clazz) {
    
    Logger logger = LogManager.getLogger(clazz);

    if (logger instanceof AbstractLogger) {
      log = new Log4j2AbstractLoggerImpl((AbstractLogger) logger);
    } else {
      log = new Log4j2LoggerImpl(logger);
    }
  }

    static{
    tryImplementation(LogFactory::useSlf4jLogging);
    tryImplementation(LogFactory::useCommonsLogging);
    tryImplementation(LogFactory::useLog4J2Logging);
    tryImplementation(LogFactory::useLog4JLogging);
    tryImplementation(LogFactory::useJdkLogging);
    tryImplementation(LogFactory::useNoLogging);
}

mybatis 日志工程中 在静态代码块会按照顺加载第三方的日志框架 ，
如果没有找到Slf4jLogging，就会执行下个
日志工程中Log接口的 实现类中会实现第三方的日志框架的方法

当没有引入依赖是 为什么它执行 tryImplementation(LogFactory::useLog4J2Logging); 不会报错 而是继续执行下一个

实现类中不是使用了该依赖中的代码吗？

和 tryImplementation（）方法中的 run()方法有关吗?

怎么做到动态寻找第三方日志框架的？

看你的依赖都没引进来，你引进来后贴下日志看下