当从docker容器连接到主机mysql db时，拒绝连接。

Question

我试图从一个运行在docker容器内的spring应用连接到运行在主机（localhost）上的mysql服务器。

这是我的Docker文件

FROM openjdk:11
ADD build/libs/demo-0.0.1-SNAPSHOT.jar demo.jar
EXPOSE 8000
RUN mkdir -p tmp/scripts
RUN mkdir -p tmp/logs
ENTRYPOINT ["java","-jar","/demo.jar"]

我正在使用Docker desktop for mac v2.3.0.3与引擎版本19.03.8。

这是hikariCP数据源连接的属性。

spring.datasource.jdbcUrl=jdbc:mysql://**host.docker.internal:3306**/freshid
spring.datasource.username=sa
spring.datasource.password=test

当我建立 docker build -f Dockerfile -t demo . 并将图像运行为 docker run -p 8000:8000 demo

在应用程序启动时，我得到以下错误信息

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)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)
    at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138)
    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:354)
    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:202)
    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:473)
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:554)
    ... 64 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: 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 java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91)
    at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
    ... 72 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
    at java.base/java.net.Socket.connect(Socket.java:609)
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65)
    ... 75 common frames omitted

Answer 1

我建议采用一个简单的解决方案。

第一步：Turboshooting。尝试在你的机器上运行springboot应用，在容器之外。如果运行正常，那么说明你的应用程序没有问题。(确保在本地测试时，你把你的DB连接字符串从 host.docker.internal 到 localhost)

第二步：请公开您的DB端口，即是 3306 当你用命令运行Docker容器时，默认情况下，mysql的情况下。

docker run -p 8000:8000 -p 3306:3306 demo

这应该可以解决你的问题"■▄▄■▓。

Answer 2

我卸载并重新安装了docker(19.03.8)，它工作了。最后的连接字符串是 jdbc:mysql://host.docker.internal:3306/db. 这并不能得出任何技术正确性的结论，但它的工作。谢谢。