2024-08-01 11:43:09 tandt | java.lang.NullPointerException: Cannot invoke “org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(java.sql.SQLException, String)” because the return value of “org.hibernate.resource.transaction.backend.jdbc.internal.JdbcIsolationDelegate.sqlExceptionHelper()” is null
2024-08-01 11:43:09 tandt | at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcIsolationDelegate.delegateWork(JdbcIsolationDelegate.java:116) ~[hibernate-core-6.4.4.Final.jar!/:6.4.4.Final]
…
2024-08-01 11:43:12 tandt | Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
2024-08-01 11:43:12 tandt |
2024-08-01 11:43:12 tandt | The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
…
2024-08-01 11:43:12 tandt | Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
2024-08-01 11:43:12 tandt |
2024-08-01 11:43:12 tandt | The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
…
2024-08-01 11:43:12 tandt | Caused by: java.net.ConnectException: Connection refused
2024-08-01 11:43:12 tandt | at java.base/sun.nio.ch.Net.connect0(Native Method) ~[na:na]
2024-08-01 11:43:12 tandt | at java.base/sun.nio.ch.Net.connect(Net.java:589) ~[na:na]
2024-08-01 11:43:12 tandt | at java.base/sun.nio.ch.Net.connect(Net.java:578) ~[na:na]
2024-08-01 11:43:12 tandt | at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:583) ~[na:na]

application.properties

spring.datasource.url                                    = ${SPRING_DATASOURCE_URL:jdbc:mysql://localhost:3306/tandt}
spring.driver.class.name                                 = com.mysql.cj.jdbc.Driver
spring.datasource.username                               = ${MYSQL_USERNAME:root}
spring.datasource.password                               = ${MYSQL_PASSWORD:uR65xvVH1y4FkrxPCqJX1s}
spring.jpa.hibernate.ddl-auto                            = update
spring.jpa.properties.hibernate.dialect                  = org.hibernate.dialect.MySQL8Dialect

docker-compose.yml

version: '3.8'
services:
  tandtdb:
    image: mysql:latest
    container_name: tandtdb
    ports:
      - "3306:3306"
    networks:
      - network-backend
    environment:
      - MYSQL_DATABASE=tandt
      - MYSQL_ROOT_PASSWORD=uR65xvVH1y4FkrxPCqJX1s
    volumes:
      - tandtdb:/var/lib/mysql

  tandtrest:
    build:
      context: .
      dockerfile: Dockerfile
    image: tandtrest:1.0.0
    container_name: tandt
    ports:
      - "8080:8080"
    networks:
      - network-backend
    environment:
      - SPRING_DATASOURCE_URL=jdbc:mysql://tandtdb:3306/tandt
      - MYSQL_USERNAME=root
      - MYSQL_PASSWORD=uR65xvVH1y4FkrxPCqJX1s
    depends_on:
      - tandtdb

networks:
  network-backend:
volumes:
  tandtdb:

please help me, thanks!