Reason analysis:

By default, dubbo uses log4j as its logging framework. If you use a different logging framework, you may not have a log.

Solve:

It can be resolved by configuring the logger attribute of the application

//slf4j,jcl,log4j,jdk,log4j2
<dubbo:application logger="log4j2" />

The old version supports log4j2:

If the old version of dubbo is used, the log4j2 adapter can be implemented through the official configuration interface without supporting log4j2.

1. Implementing adapters

import com.alibaba.dubbo.common.logger.Level;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerAdapter;
import org.apache.logging.log4j.LogManager;

import java.io.File;

public class Log4j2LoggerAdapter implements LoggerAdapter {

    private Level level;

    public Log4j2LoggerAdapter() {

    }

    private static org.apache.logging.log4j.Level toLog4j2Level(Level level) {
        if (level == Level.ALL) {
            return org.apache.logging.log4j.Level.ALL;
        }
        if (level == Level.TRACE) {
            return org.apache.logging.log4j.Level.TRACE;
        }
        if (level == Level.DEBUG) {
            return org.apache.logging.log4j.Level.DEBUG;
        }
        if (level == Level.INFO) {
            return org.apache.logging.log4j.Level.INFO;
        }
        if (level == Level.WARN) {
            return org.apache.logging.log4j.Level.WARN;
        }
        if (level == Level.ERROR) {
            return org.apache.logging.log4j.Level.ERROR;
        }
        return org.apache.logging.log4j.Level.OFF;
    }

    private static Level fromLog4j2Level(org.apache.logging.log4j.Level level) {
        if (level == org.apache.logging.log4j.Level.ALL) {
            return Level.ALL;
        }
        if (level == org.apache.logging.log4j.Level.TRACE) {
            return Level.TRACE;
        }
        if (level == org.apache.logging.log4j.Level.DEBUG) {
            return Level.DEBUG;
        }
        if (level == org.apache.logging.log4j.Level.INFO) {
            return Level.INFO;
        }
        if (level == org.apache.logging.log4j.Level.WARN) {
            return Level.WARN;
        }
        if (level == org.apache.logging.log4j.Level.ERROR) {
            return Level.ERROR;
        }
        return Level.OFF;
    }

    @Override
    public Logger getLogger(Class<?> key) {
        return new Log4j2Logger(LogManager.getLogger(key));
    }

    @Override
    public Logger getLogger(String key) {
        return new Log4j2Logger(LogManager.getLogger(key));
    }

    @Override
    public Level getLevel() {
        return level;
    }

    @Override
    public void setLevel(Level level) {
        this.level = level;
    }

    @Override
    public File getFile() {
        return null;
    }

    @Override
    public void setFile(File file) {
    }
}

 

import com.alibaba.dubbo.common.logger.Logger;

public class Log4j2Logger implements Logger {

    private final org.apache.logging.log4j.Logger logger;

    public Log4j2Logger(org.apache.logging.log4j.Logger logger) {
        this.logger = logger;
    }

    @Override
    public void trace(String msg) {
        logger.trace(msg);
    }

    @Override
    public void trace(Throwable e) {
        logger.trace(e == null ? null : e.getMessage(), e);
    }

    @Override
    public void trace(String msg, Throwable e) {
        logger.trace(msg, e);
    }

    @Override
    public void debug(String msg) {
        logger.debug(msg);
    }

    @Override
    public void debug(Throwable e) {
        logger.debug(e == null ? null : e.getMessage(), e);
    }

    @Override
    public void debug(String msg, Throwable e) {
        logger.debug(msg, e);
    }

    @Override
    public void info(String msg) {
        logger.info(msg);
    }

    @Override
    public void info(Throwable e) {
        logger.info(e == null ? null : e.getMessage(), e);
    }

    @Override
    public void info(String msg, Throwable e) {
        logger.info(msg, e);
    }

    @Override
    public void warn(String msg) {
        logger.warn(msg);
    }

    @Override
    public void warn(Throwable e) {
        logger.warn(e == null ? null : e.getMessage(), e);
    }

    @Override
    public void warn(String msg, Throwable e) {
        logger.warn(msg, e);
    }

    @Override
    public void error(String msg) {
        logger.error(msg);
    }

    @Override
    public void error(Throwable e) {
        logger.error(e == null ? null : e.getMessage(), e);
    }

    @Override
    public void error(String msg, Throwable e) {
        logger.error(msg, e);
    }

    @Override
    public boolean isTraceEnabled() {
        return logger.isTraceEnabled();
    }

    @Override
    public boolean isDebugEnabled() {
        return logger.isDebugEnabled();
    }

    @Override
    public boolean isInfoEnabled() {
        return logger.isInfoEnabled();
    }

    @Override
    public boolean isWarnEnabled() {
        return logger.isWarnEnabled();
    }

    @Override
    public boolean isErrorEnabled() {
        return logger.isErrorEnabled();
    }
}

2. Configuring spi

New files in / src/main/resources/META-INF/dubbo directory

File name: com.alibaba.dubbo.common.logger.LoggerAdapter

The content of the file is log4j2 = com. wisedu. wec. cpdaily. config. provider. common. log4j2. Log4j2Logger Adapter

3. Configure dubbo to use logger

//slf4j,jcl,log4j,jdk,log4j2
<dubbo:application logger="log4j2" />

For more extended implementations, see the official instructions: http://dubbo.apache.org/zh-cn/docs/dev/impls/logger-adapter.html