docker - 尝试到达Docker容器时的“Unable to connect”

Question

我正在尝试学习Docker，但我什至无法入门:(

我做了一个微服务，如果您调用它，它只会返回“测试”。如果运行java -jar test.jar并转到localhost:8080，浏览器将显示预期结果:



但是，如果我使用Docker部署该JAR，则无法访问该页面:



这是我的Dockerfile:

FROM openjdk:8-jdk-alpine

ARG JAR_FILE=test.jar
ARG PORT=8080

EXPOSE ${PORT}

VOLUME /tmp
ADD ${JAR_FILE} app.jar

ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

docker build -t test .

Sending build context to Docker daemon   16.2MB
Step 1/7 : FROM openjdk:8-jdk-alpine
 ---> 5801f7d008e5
Step 2/7 : ARG JAR_FILE=test.jar
 ---> Using cache
 ---> 7095632eee4a
Step 3/7 : ARG PORT=8080
 ---> Using cache
 ---> 4a1351be9f66
Step 4/7 : EXPOSE ${PORT}
 ---> Using cache
 ---> 6f7958533a34
Step 5/7 : VOLUME /tmp
 ---> Using cache
 ---> 6bafa2fa82cf
Step 6/7 : ADD ${JAR_FILE} app.jar
 ---> Using cache
 ---> 2dc3da720820
Step 7/7 : ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
 ---> Using cache
 ---> 60348d53cf97
Successfully built 60348d53cf97
Successfully tagged test:latest

docker run test -p 8080:8080

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.4.RELEASE)

2018-09-03 18:53:26.595  INFO 1 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication v0.0.1-SNAPSHOT on 81a95eb3474a with PID 1 (/app.jar started by root in /)
2018-09-03 18:53:26.599  INFO 1 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2018-09-03 18:53:26.669  INFO 1 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@12f40c25: startup date [Mon Sep 03 18:53:26 GMT 2018]; root of context hierarchy
2018-09-03 18:53:28.215  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2018-09-03 18:53:28.253  INFO 1 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2018-09-03 18:53:28.253  INFO 1 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.32
2018-09-03 18:53:28.272  INFO 1 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener   : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [/usr/lib/jvm/java-1.8-openjdk/jre/lib/amd64/server:/usr/lib/jvm/java-1.8-openjdk/jre/lib/amd64:/usr/lib/jvm/java-1.8-openjdk/jre/../lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib]
2018-09-03 18:53:28.355  INFO 1 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2018-09-03 18:53:28.356  INFO 1 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1691 ms
2018-09-03 18:53:28.422  INFO 1 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Servlet dispatcherServlet mapped to [/]
2018-09-03 18:53:28.426  INFO 1 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-09-03 18:53:28.427  INFO 1 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-09-03 18:53:28.427  INFO 1 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-09-03 18:53:28.427  INFO 1 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2018-09-03 18:53:28.589  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-03 18:53:28.833  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@12f40c25: startup date [Mon Sep 03 18:53:26 GMT 2018]; root of context hierarchy
2018-09-03 18:53:28.944  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public java.lang.String com.example.demo.NewRestController.getTEst()
2018-09-03 18:53:28.949  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-09-03 18:53:28.950  INFO 1 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-09-03 18:53:28.977  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-03 18:53:28.977  INFO 1 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-09-03 18:53:29.140  INFO 1 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-09-03 18:53:29.191  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-09-03 18:53:29.195  INFO 1 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 3.008 seconds (JVM running for 3.491)

docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
81a95eb3474a        test                "java -Djava.securit…"   2 minutes ago       Up 2 minutes        8080/tcp            happy_feynman

我已经坚持了一天多了，我无法解决这个问题。我该怎么办？

Answer 1

将docker run test -p 8080:8080更改为docker run -p 8080:8080 test作为当前语法，而不是暴露localhost上的端口，而是将-p 8080:8080作为参数传递给程序。您可以在docker ps中看到它，其中在端口下只有8080/tcp，这意味着您的端口暴露在docker网络内部-并未映射到主机。更多信息:https://docs.docker.com/engine/reference/run/