相关疑难解决方法(0)

我正在尝试连接到本地MySQL服务器,但我一直收到错误.

这是代码.

public class Connect {

    public static void main(String[] args) {
        Connection conn = null;

        try {
            String userName = "myUsername";
            String password = "myPassword";

            String url = "jdbc:mysql://localhost:3306/myDatabaseName";
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            conn = DriverManager.getConnection(url, userName, password);
            System.out.println("Database connection established");
        } catch (Exception e) {
            System.err.println("Cannot connect to database server");
            System.err.println(e.getMessage());
            e.printStackTrace();
        } finally {
            if (conn != null) {
                try {
                    conn.close();
                    System.out.println("Database Connection Terminated");
                } catch (Exception e) {}
            }
        }
    }
}

和错误:

Cannot connect to database server …

当我尝试在同一台机器上连接两个 docker 容器时，一个运行node.js 服务器，另一个运行mysql dbms

(node:32) UnhandledPromiseRejectionWarning: Error: getaddrinfo ENOTFOUND jdbc:mysql://localhost:3306 jdbc:mysql://localhost:3306:3306

const connection= mysql.createConnection({
  host: 'jdbc:mysql://topsectiondb:3306',
  user: 'root',
  password: 'rootpass' 
})

version: '3'
services:
  topsection:
    container_name: topsection-server
    restart: always
    build: .
    ports:
      - '7777:7777'
    depends_on: 
      - topsectiondb
    environment:
      - PORT=7777
  topsectiondb:
    container_name: topsectiondb
    image: mysql:8.0.3
    ports:
      - '3306:3306'
    environment:
      - MYSQL_ROOT_PASSWORD=rootpass

FROM node:10

RUN mkdir serviceFolder

WORKDIR /usr/app/

COPY . . 

RUN npm install

EXPOSE 7777

CMD ["npm", …