如何运行 akka grpc java 示例

Question

好的，按照先决条件和说明使用Java 8 项目创建成功。

sbt new akka/akka-grpc-quickstart-java.g8

然后继续 guide

./gradlew compileJava 也有效。

但随后 ./gradlew --info runServer 失败并出现以下 errors/issues:

Task ':runServer' is not up-to-date because:
Task has not declared any outputs.

和

Error: Main method not found in class com.example.helloworld.GreeterServer, please define the main method as:
   public static void main(String[] args)

原版POST:

我在获取 Akka-GRPC 示例到运行时遇到问题。我尝试关注 this guide here 但是当我下载示例项目时它似乎不完整。

这就是树命令输出：

.
├── build.sbt
├── project
│   ├── build.properties
│   └── plugins.sbt
├── sbt
├── sbt.bat
└── sbt-dist
    ├── bin
    │   ├── sbt
    │   ├── sbt.bat
    │   ├── sbt-launch.jar
    │   └── sbt-launch-lib.bash
    └── conf
        ├── sbtconfig.txt
        └── sbtopts

4 directories, 11 files

项目结构中没有源文件或 gradlew oder pom.xml。

接下来我克隆了 repository of that example from GitHub 并按照自述文件中的说明进行操作，主要是命令 sbt new akka/akka-grpc-quickstart-java.g8.

$ sbt new akka/akka-grpc-quickstart-java.g8
[info] Loading settings for project akka-grpc-quickstart-java-g8-build from paradox.sbt,giter8.sbt ...
[info] Loading project definition from /home/johannes/IdeaProjects/akka-grpc-quickstart-java.g8/project
error: error while loading String, class file '/modules/java.base/java/lang/String.class' is broken
(class java.lang.NullPointerException/null)
[error] java.io.IOError: java.lang.RuntimeException: /packages cannot be represented as URI
...//had to remove stacktrace was too long for this post
[error]     at xsbt.boot.Boot.main(Boot.scala)
Project loading failed: (r)etry, (q)uit, (l)ast, or (i)gnore? [error] java.io.IOError: java.lang.RuntimeException: /packages cannot be represented as URI
[error] Use 'last' for the full log.

然后我进入源文件所在的 project/sources 文件夹 ./src/main/g8/ 并尝试按照那里的指南中的说明进行操作。由于某些属性错误，这也不起作用：

在此之前，我必须在 ./gradle/wrapper/gradle-wrapper.properties 中设置另一个 gradle 版本（6.1.1，是 4.5.1）以使其与 Java 13.

$ ./gradlew compileJava

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'g8'.
> Could not resolve all artifacts for configuration ':classpath'.
   > Could not find gradle.plugin.com.lightbend.akka.grpc:akka-grpc-gradle-plugin:$akka_grpc_version$.
     Searched in the following locations:
       - file:/home/johannes/.m2/repository/gradle/plugin/com/lightbend/akka/grpc/akka-grpc-gradle-plugin/$akka_grpc_version$/akka-grpc-gradle-plugin-$akka_grpc_version$.pom
       - https://plugins.gradle.org/m2/gradle/plugin/com/lightbend/akka/grpc/akka-grpc-gradle-plugin/$akka_grpc_version$/akka-grpc-gradle-plugin-$akka_grpc_version$.pom
     Required by:
         project :

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 4s

为了至少暂时让它工作，我将属性硬编码到 build.gradle 文件中：

     //classpath 'gradle.plugin.com.lightbend.akka.grpc:akka-grpc-gradle-plugin:$akka_grpc_version$'
     classpath 'gradle.plugin.com.lightbend.akka.grpc:akka-grpc-gradle-plugin:0.7.3'

但这也只是让我到目前为止：

$ ./gradlew compileJava

FAILURE: Build failed with an exception.

* Where:
Build file '/home/johannes/IdeaProjects/akka-grpc-quickstart-java.g8/src/main/g8/build.gradle' line: 20

* What went wrong:
A problem occurred evaluating root project 'g8'.
> Failed to apply plugin [id 'com.google.protobuf']
   > Could not create an instance of type com.google.protobuf.gradle.ProtobufSourceDirectorySet.
      > 'void org.gradle.api.internal.file.DefaultSourceDirectorySet.<init>(java.lang.String, java.lang.String, org.gradle.api.internal.file.FileResolver, org.gradle.api.internal.file.collections.DirectoryFileTreeFactory)'

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s

由于字符限制，再次无法包含整个堆栈跟踪。

我错过了什么？我应该进一步采用哪种方法？

Answer 1

编辑：同时，拉取请求被接受并且主回购（https://github.com/akka/akka-grpc-quickstart-java.g8）是最新的。

我使用 sbt new ... 下载了项目，但是 pom.xml（固定版本：https://github.com/olitazl/akka-grpc-quickstart-java.g8）

中出现错误

示例项目的问题 GreeterServer class.

中缺少 public 修饰符

因此，您必须将 public 添加到 GreeterServer class 和其中的方法 main。

    public class GreeterServer ...
    public static void main(...)

如果您从我的存储库重新创建项目，问题也已解决。

如何 运行 akka grpc java 示例

How to run the akka grpc java example

java

gradle

akka

akka-grpc

如何运行 akka grpc java 示例