当 mysql 连接器位于同一项目中时，如何从命令行运行连接数据库的 Java 程序？

Question

I have written Java code that connects to a database, all works great in IntelliJ, as the connector is configured via the IDE. However, when I try to run the same code from the commandline, I run into some problems.

Firstly, I used the command:

javac -encoding UTF8 -cp mysql/mysql-connector-java-8.0.19.jar Main.java Logic.java

for compiling my Java files, (I've tried the same things with just javac -encoding UTF8 *.java as well) and then I have tried to run my Java program.

If I use "java Main.java" on the commandline, I get an error:

java.sql.SQLException: No suitable driver found for jdbc:mysql:***.

However, when I try to run java -cp mysql/mysql-connector-java-8.0.19.jar Main.java , I get the error:

Main.java:10: error: package Logic does not exist

I have tried to get it to work by moving the entire jar to the same folder as my files and also tried extracting the Driver.class file from the jar, yet I still can not get it to work.

I realise this was not probably the most efficient way to connect a database anyways, but this is where I am at. Sorry if it is a stupid question, but I have been at it for hours. Thanks!

Answer 1

IDEs are very helpful to provide a simple "sandbox" where you can work visually on the code, build it, run it, and debug it fast.

However, when you want to publish or deploy your application so it can be run outside your sandbox, you probably need to perform a "standard build". This standard build will produce an application that can be run anywhere.

Solution? Use any build tool, such as Maven, Ant, or Gradle. You'll need to learn the basics of the one you choose. There are plenty of examples online. Also, pretty much all IDEs provide integration with those three I mention.

You'll need to decide if you want to include the JDBC driver inside the application itself or as an external dependency, as well. Options, options, options.