我无法理解为什么这段代码不起作用：
com.zaxxer.hikari.pool.HikariPool$PoolInitializationException: Failed to initialize pool: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:528)
at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:118)
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:94)
at liquibase.integration.spring.SpringLiquibase.afterPropertiesSet(SpringLiquibase.java:388)
at eu.biasion.nbmf.config.liquibase.AsyncSpringLiquibase.initDb(AsyncSpringLiquibase.java:66)
at eu.biasion.nbmf.config.liquibase.AsyncSpringLiquibase.lambda$afterPropertiesSet$0(AsyncSpringLiquibase.java:49)
at eu.biasion.nbmf.async.ExceptionHandlingAsyncTaskExecutor.lambda$createWrappedRunnable$17(ExceptionHandlingAsyncTaskExecutor.java:47)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
dest文件路径不是真的吗？ 我想在public_html目录中上传文件，这是ftp帐户的起始目录。 我要上传的文件位于php脚本的同一目录中， 我得到的错误是在ftp put函数中， 有谁可以帮助我？