未能用Maven构建应用程序，我可以在本地运行代码，但未能在heroku上部署

Question

这是我在github:https://github.com/q463746583/cs4500-assignment2中的代码，我可以在本地成功地运行它，但是当我试图在heroku上部署代码时，出现了错误描述：

       [INFO] Downloaded from central: https://repo.maven.apache.org/maven2/com/thoughtworks/qdox/qdox/2.0-M9/qdox-2.0-M9.jar (317 kB at 6.0 MB/s)
       [INFO] Changes detected - recompiling the module!
       [INFO] Compiling 4 source files to /tmp/build_3c4f3b86a26f6e3ae1cbe89639f79f26/target/classes
       [INFO] ------------------------------------------------------------------------
       [INFO] BUILD FAILURE
       [INFO] ------------------------------------------------------------------------
       [INFO] Total time: 13.261 s
       [INFO] Finished at: 2019-01-24T00:47:07Z
       [INFO] ------------------------------------------------------------------------
       [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project myapp: Fatal error compiling: invalid target release: 11 -> [Help 1]
       [ERROR] 
       [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
       [ERROR] Re-run Maven using the -X switch to enable full debug logging.
       [ERROR] 
       [ERROR] For more information about the errors and possible solutions, please read the following articles:
       [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
 !     ERROR: Failed to build app with Maven
       We're sorry this build is failing! If you can't find the issue in application code,
       please submit a ticket so we can help: https://help.heroku.com/
 !     Push rejected, failed to compile Java app.
 !     Push failed

Answer 1

我认为这与Heroku上的目标Java运行时环境和从Maven编译器生成的本地编译代码之间的不匹配有关，您正试图将这些代码推送到Heroku。

根据Heroku的文件：

Heroku目前默认使用OpenJDK8来运行应用程序。OpenJDK版本9和版本7也是可用的。

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pom.xml：

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.1</version>
    <configuration>
        <source>1.7</source>
        <target>1.7</target>
    </configuration>
</plugin>

那么，如果您的目标是Heroku默认的JDK1.8运行时环境以外的运行时环境，则应该在项目中创建system.properties文件。您可以通过指定所需的java运行时环境来做到这一点，如下所示：

System.Properties：

java.runtime.version=11

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希望能有所帮助