How to connect to external port DB in docker [duplicate] - spring

Question

I'm working with spring boot, hibernate & MySql. While running the application it is running well as per expectation . But while making the docker-compose file and running the app docker image with mysql docker image it gives this error.
Error
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
java.net.ConnectException: Connection refused.
private Connection createConnection() throws SQLException
{
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
String mysqlUrl = "jdbc:mysql://localhost/database?autoReconnect=true&useSSL=false";
Connection connection = DriverManager.getConnection(mysqlUrl, "root", "root");
return connection;
}
Application.properties
spring.datasource.url=jdbc:mysql://localhost/database?autoReconnect=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=root
Please guide me how to tackle this.
docker-compose.yml
version: '3'
services:
docker-mysql:
image: mysql:5.7
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=database
- MYSQL_USER=root
- MYSQL_PASSWORD=root
ports:
- 3307:3306
app:
image: app:latest
ports:
- 8091:8091
depends_on:
- docker-mysql

Answer 1

Issue is due to reference of localhost in the jdbc url.
Below configuration should work.
**docker-compose.yml**
version: '3'
services:
docker-mysql:
image: mysql:5.7
environment:
- MYSQL_ROOT_PASSWORD=root
- MYSQL_DATABASE=database
- MYSQL_USER=root
- MYSQL_PASSWORD=root
ports:
- 3307:3306
app:
image: app:latest
ports:
- 8091:8091
environment:
SPRING_DATASOURCE_URL: jdbc:mysql://docker-mysql:3306/database?autoReconnect=true&useSSL=false
depends_on:
- docker-mysql

Answer 2

This Docker forum discussion helped me when I was running into this error. For me it was a problem with cache and I didn't get the error after running docker-compose down --rmi all

Answer 3

For me, it was the version of mysql
image: mysql:8 -> image: mysql:5.7

Answer 4

did you tell your docker that it depends on SQL?
I mean is there something like this:
depends_on:
- mysql_server
in your docker-compose.yml ?
looks like a configuration issue.

Answer 5

In my case I have provided proper privilege for my user to get connected from docker host and the error war gone.
I have provided % as host for my user which will provide access to connect from any host. The default root user will only connects from localhost.

Answer 6

Put something like this in the application.properties
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:${MYSQL_PORT:3306}/test
spring.datasource.username=${MYSQL_USER:root}
spring.datasource.password=${MYSQL_PASSWORD:password}