将 PostgreSQL 数据库连接到 Spring 应用程序（均在 docker 中运行）连接被拒绝

Question

I've been trying to establish connection between my Spring app and PostgreSQL database. Both the database and app are started in docker containers. The point is that when the docker-compose up is executed, console logs indicate that connection to localhost:5432 has been refused. I managed to connected to the database via python successfully but I wasn't able to establish the connection in java, thus to help I added content of every file that was used to establish the connection. My team and I would greatly appreciate even minor help!

medical-clinic | org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
medical-clinic |        at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:303) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:51) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:225) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.Driver.makeConnection(Driver.java:465) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.Driver.connect(Driver.java:264) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-3.4.5.jar!/:na]
medical-clinic |        at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:176) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255) ~[hibernate-core-5.4.21.Final.jar!/:5.4.21.Final]
medical-clinic |        at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
medical-clinic |        at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
medical-clinic |        at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:391) ~[spring-orm-5.2.9.RELEASE.jar!/:5.2.9.RELEASE]
medical-clinic |        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
medical-clinic |        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
medical-clinic |        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
medical-clinic |        at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
medical-clinic | Caused by: java.net.ConnectException: Connection refused (Connection refused)
medical-clinic |        at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
medical-clinic |        at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]
medical-clinic |        at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]
medical-clinic |        at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]
medical-clinic |        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403) ~[na:na]
medical-clinic |        at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na]
medical-clinic |        at org.postgresql.core.PGStream.createSocket(PGStream.java:231) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.core.PGStream.<init>(PGStream.java:95) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:98) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:213) ~[postgresql-42.2.18.jar!/:42.2.18]
medical-clinic |        ... 34 common frames omitted

Here is my docker-compose.yml file:

version: '3'

services:
  db:
    image: 'postgres:13.1-alpine'
    container_name: db
    environment:
      - POSTGRES_DB=MedClinic
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=123
      
      - ALLOW_IP_RANGE-0.0.0.0/0
    volumes:
      - ./src/main/resources/db/init.sql:/docker-entrypoint-initdb.d/1-schema.sql
      - ./src/main/resources/db/data.sql:/docker-entrypoint-initdb.d/2-data.sql
    ports:
      - "5432:5432"
  app:
    image: 'medical-clinic:latest'
    build:
      context: .
    container_name: 'medical-clinic'
    ports:
      - 8080:8080
    environment:
      - SPRING_DATASOURCE_URL=jdbc:postgresql://localhost:5432/MedClinic
      - SPRING_DATASOURCE_USERNAME=postgres
      - SPRING_DATASOURCE_PASSWORD=123
      - SPRING_JPA_HIBERNATE_DDL_AUTO=update
    depends_on:
      - db

the pom.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.company</groupId>
    <artifactId>medical-clinic</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>medical-clinic</name>
    <description>Medical clinic app</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.18</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

and the application.properties

spring.datasource.url=jdbc:postgresql://localhost:5432/MedClinic
spring.datasource.username=postgres
spring.datasource.password=123
spring.datasource.driver-class-name=org.postgresql.Driver
# Keep the connection alive if idle for a long time (needed in production)
spring.datasource.testWhileIdle=true
spring.datasource.validationQuery=SELECT 1
# ===============================
# = JPA / HIBERNATE
# ===============================
# Show or not log for each sql query
spring.jpa.show-sql=true
# Hibernate ddl auto (create, create-drop, update): with "create-drop" the database
# schema will be automatically created afresh for every start of application
spring.jpa.hibernate.ddl-auto=create-drop

# Naming strategy
spring.jpa.hibernate.naming.implicit-strategy=org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyHbmImpl
spring.jpa.hibernate.naming.physical-strategy=org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy

# Allows Hibernate to generate SQL optimized for a particular DBMS
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect

Answer 1

you might just have a simple timing problem. Having the db dependsOn in your docker-compose.yaml sets up network visibility. But: Docker Compose can not know, when your Postgres Container is ready to accept connections. Your application might just try to accesss Postgres to early? Have a look into the official manual, they actual base a sample on Postgres: https://docs.docker.com/compose/startup-order/