tomcat配置数据源 mysql

<Context>
    <Resource name="jdbc/MyDB"
              auth="Container"
              type="javax.sql.DataSource"
              username="your_username"
              password="your_password"
              driverClassName="com.mysql.cj.jdbc.Driver"
              url="jdbc:mysql://localhost:3306/your_database"
              maxTotal="20"
              maxIdle="10"
              maxWaitMillis="-1"/>
</Context>

<web-app>
    <resource-ref>
        <description>DB Connection</description>
        <res-ref-name>jdbc/MyDB</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>
</web-app>

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

public class DBUtil {
    private static DataSource dataSource;

    static {
        try {
            Context ctx = new InitialContext();
            dataSource = (DataSource) ctx.lookup("java:comp/env/jdbc/MyDB");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }
}