logback中打印sql语句

To log SQL statements for particular mybatis mapper set DEBUG (TRACE to see query parameters and results) level for logger with fully qualified mapper name

这里的name值mapper接口的全限定名

<logger name="com.mycompany.myapp.mapper.MyMapper" level="DEBUG"/>

You can log all SQL statements from all mappers if they are in the same package like this

这里的name值mapper接口所在的包名

<logger name="com.mycompany.myapp.mapper" level="DEBUG"/>

日志的级别需要是DEBUG

原因：mybatis源代码BaseExceutor.java

protected Connection getConnection(Log statementLog) throws SQLException {
    Connection connection = transaction.getConnection();
    if (statementLog.isDebugEnabled()) {
        return ConnectionLogger.newInstance(connection, statementLog, queryStack);
    } else {
        return connection;
    }
}

refer:http://stackoverflow.com/questions/21718097/how-to-configure-logback-for-mybatis-to-print-my-sql