com.mysql.cj.jdbc.exceptions.CommunicationsException：尝试构建 Spring Boot Docker 映像时通信链接失败答案

【问题标题】：com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure when trying to build spring boot docker imagecom.mysql.cj.jdbc.exceptions.CommunicationsException：尝试构建 Spring Boot Docker 映像时通信链接失败
【发布时间】：2020-09-18 12:52:07
【问题描述】：

我正在尝试为我的 Spring Boot 应用程序构建我的 Docker 映像，但一直遇到此错误：

 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.5.RELEASE)

2020-05-31 02:18:39.820  INFO 63 --- [           main] c.g.Apollo.ApolloApplicationTests        : Starting ApolloApplicationTests on 4b284b60945e with PID 63 (started by root in /build)
2020-05-31 02:18:39.838  INFO 63 --- [           main] c.g.Apollo.ApolloApplicationTests        : No active profile set, falling back to default profiles: default
2020-05-31 02:18:42.208  INFO 63 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2020-05-31 02:18:42.467  INFO 63 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 216ms. Found 3 JPA repository interfaces.
2020-05-31 02:18:44.902  INFO 63 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2020-05-31 02:18:46.575 ERROR 63 --- [           main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Exception during pool initialization.

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
        at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.20.jar:8.0.20]
        at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:354) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:202) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:473) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:554) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-3.4.2.jar:na]
        at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-3.4.2.jar:na]

在intellij中成功运行时的终端：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.5.RELEASE)

2020-05-31 01:04:39.322  INFO 19524 --- [  restartedMain] c.g.Apollo.ApolloApplication             : Starting ApolloApplication on asd-PC with PID 19524 (C:\Projects\Apollo\target\classes started by asd in C:\Projects\Apollo)
2020-05-31 01:04:39.324  INFO 19524 --- [  restartedMain] c.g.Apollo.ApolloApplication             : No active profile set, falling back to default profiles: default
2020-05-31 01:04:39.354  INFO 19524 --- [  restartedMain] o.s.b.devtools.restart.ChangeableUrls    : The Class-Path manifest attribute in C:\Users\asd\.m2\repository\org\glassfish\jaxb\jaxb-runtime\2.3.2\jaxb-runtime-2.3.2.jar referenced one or more files that do not exist: file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/jakarta.xml.bind-api-2.3.2.jar,file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/txw2-2.3.2.jar,file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/istack-commons-runtime-3.0.8.jar,file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/stax-ex-1.8.1.jar,file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/FastInfoset-1.2.16.jar,file:/C:/Users/asd/.m2/repository/org/glassfish/jaxb/jaxb-runtime/2.3.2/jakarta.activation-api-1.2.1.jar
2020-05-31 01:04:39.354  INFO 19524 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2020-05-31 01:04:39.354  INFO 19524 --- [  restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : For additional web related logging consider setting the 'logging.level.web' property to 'DEBUG'
2020-05-31 01:04:39.785  INFO 19524 --- [  restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2020-05-31 01:04:39.846  INFO 19524 --- [  restartedMain] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 54ms. Found 3 JPA repository interfaces.
2020-05-31 01:04:40.214  INFO 19524 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2020-05-31 01:04:40.220  INFO 19524 --- [  restartedMain] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-05-31 01:04:40.221  INFO 19524 --- [  restartedMain] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.31]
2020-05-31 01:04:40.293  INFO 19524 --- [  restartedMain] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-05-31 01:04:40.293  INFO 19524 --- [  restartedMain] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 939 ms
2020-05-31 01:04:40.365  INFO 19524 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2020-05-31 01:04:40.702  INFO 19524 --- [  restartedMain] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2020-05-31 01:04:40.731  INFO 19524 --- [  restartedMain] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2020-05-31 01:04:40.800  INFO 19524 --- [  restartedMain] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.12.Final
2020-05-31 01:04:40.919  INFO 19524 --- [  restartedMain] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
2020-05-31 01:04:41.006  INFO 19524 --- [  restartedMain] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.MySQL8Dialect
2020-05-31 01:04:41.407  INFO 19524 --- [  restartedMain] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2020-05-31 01:04:41.413  INFO 19524 --- [  restartedMain] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2020-05-31 01:04:41.650  WARN 19524 --- [  restartedMain] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2020-05-31 01:04:41.717  INFO 19524 --- [  restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2020-05-31 01:04:41.967  INFO 19524 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2020-05-31 01:04:41.995  INFO 19524 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2020-05-31 01:04:41.997  INFO 19524 --- [  restartedMain] c.g.Apollo.ApolloApplication             : Started ApolloApplication in 2.911 seconds (JVM running for 3.899)

我的 Dockerfile：

FROM maven:3.6.3-jdk-11-slim AS MAVEN_BUILD

COPY pom.xml /build/
COPY src /build/src/
WORKDIR /build/
RUN mvn package

FROM openjdk:11-jre-alpine

WORKDIR /app
COPY --from=MAVEN_BUILD /build/target/*.war /app/app.war
ENTRYPOINT ["java", "-jar", "app.war"]

我的 application.properties：

## GraphQL SPQR ##
server.port=8080
graphql.spqr.gui.enabled=true
graphql.spqr.http.endpoint=/graphql
graphql.spqr.ws.endpoint=/graphql

## Database Properties ##
spring.datasource.url=jdbc:mysql://localhost:3306/innodb
spring.datasource.username=root
spring.datasource.password=1234

当我在 Intellij 中构建和运行项目时，我的应用程序可以工作，但当我尝试构建我的 docker 映像时却不行。我正在使用 MySQL，并且刚刚在 localhost 的 3306 端口上进行连接。

【问题讨论】：

始终使用安全 egd 和应用程序所在的完整路径运行 java：CMD ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app/app.jar

标签： java mysql spring-boot docker spring-data-jpa

【解决方案1】：

错误消息似乎表明问题是无法连接到数据库。根据您的设置，您似乎正在尝试使用 localhost:3306 连接到数据库。当您在容器中运行应用程序时，这将不起作用，因为 docker 创建了自己的网络，该网络与您机器的网络分开。因此，容器中的 localhost 并不指您的机器。您需要设置一个 docker 网络，该网络将允许您的容器访问特定 IP 地址中的数据库。这是一篇详细的文章： https://nickjanetakis.com/blog/docker-tip-35-connect-to-a-database-running-on-your-docker-host 请注意，我从您的帖子中假设数据库已安装在您的主机中。如果不是，并且数据库在其自己的容器中运行，则您需要创建一个 docker 网络并将两个容器都附加到该网络。

【讨论】：