java.lang.ClassNotFoundException: com.mysql.jdbc.D

问题:

I have imported my library "mysql-connector-java-5.1.39" as answered by most people to exact same question , but I am still getting this error

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver

here is the code of test class

package database;

import java.sql.Connection;
import java.sql.DriverManager;

public class Main {

    public static void main(String[] args) throws Exception {
        getConnection();
    }

    public static Connection getConnection() throws Exception {
        try{
            String driver="com.mysql.jdbc.Driver";
            String url="jdbc:mysql://localhost:3306/test";
            String username="root";
            String password="root";
            Class.forName(driver);
            Connection conn= DriverManager.getConnection(url,username,password);
            System.out.println("connected");
            return conn;
        }
        catch (Exception e){
            System.out.println(e);
        }
        return null;
    }
}

Using mac OS .

回答1:

Everybody repeat after me. ( :-) )

"java.lang.ClassNotFoundException: com.mysql.jdbc.Driver" is NOT a compilation error.

Therefore, changing the >>build<< path or adding an import cannot fix the problem.

The solution is to make sure that the JAR file is on the classpath when you run the application. For example, if your test class is in bin\database\Main.class and the driver JAR is in lib ...

$ java -classpath bin:lib/mysql-connector-java-5.1.39.jar database.Main

回答2:

If the jar is already added to your external libs, you can simply add :

import com.mysql.jdbc.Driver;

and it shall work in your class.

This shall help further SO-21580499

回答3:

Some of the most possible reasons of "java.lang.ClassNotFoundException: com.mysql.jdbc.Driver" in your code are:

1. You don't have mysql-connector.jar in your Classpath.
2. mysql-connector.jar is in your classpath but somehow your classpath is getting overridden.
3. mysql-connector.jar is in classpath but current user doesn't have read permission.

回答4:

It looks like you app cannot find the JDBC driver for Microsoft SQL server. You can download it below and add the jar to your WEB-INF/lib:

https://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=11774