Micronaut DI不适用于Maven内置的Graal Native Image

Question

我在Micronaut上有一个最小的应用程序，它看起来像这样：

@Introspected
public class BookRequestHandler extends MicronautRequestHandler<Book, BookSaved> {

    @Inject
    private BookService service;

    @Override
    public BookSaved execute(Book input) {
        return service.process(input);
    }

}

@Singleton
@Introspected
public class BookService {

  public BookSaved process(Book input) {
    BookSaved bookSaved = new BookSaved();
    bookSaved.setName(input.getName());
    bookSaved.setIsbn(UUID.randomUUID().toString());
    return bookSaved;
  }

}

• 运行时和DTO类。

我的项目使用Micronaut-的插件在Graal Native Image上成功构建并运行/mvnm

但我试图通过Docker容器直接使用本机映像进行构建。图像正在消失！但如果我尝试调用lambda，我会得到一个错误，即找不到依赖项注入字段：（此文件是从Micronaut的Gradle版本重新制作的：

# STEP 1: Packaging project .jar in Docker image 'builder'
FROM maven:3.6.3-jdk-8 as build

COPY . /home/application
WORKDIR /home/application

RUN mvn clean package

# STEP 2: Downloading Graal and C libraries in Docker image 'graalvm'
FROM amazonlinux:2018.03 as graal

ENV LANG en_US.UTF-8
ENV JDK_VERSION java8
ENV GRAAL_VERSION 21.0.0.2
ENV GRAAL_FILENAME graalvm-ce-${JDK_VERSION}-linux-amd64-${GRAAL_VERSION}.tar.gz

RUN yum install -y gcc gcc-c++ libc6-dev zlib1g-dev curl bash zlib zlib-devel zip
RUN curl -4 -L https://github.com/graalvm/graalvm-ce-builds/releases/download/vm-${GRAAL_VERSION}/${GRAAL_FILENAME} -o /tmp/${GRAAL_FILENAME}
RUN tar -zxvf /tmp/${GRAAL_FILENAME} -C /tmp
RUN mv /tmp/graalvm-ce-${JDK_VERSION}-${GRAAL_VERSION} /usr/lib/graalvm
RUN rm -rf /tmp/*

CMD ["/usr/lib/graalvm/bin/native-image"]

# STEP 3: Building and zipping a Native Image with bootstrap file
FROM graal

COPY --from=build /home/application/ /home/application/
WORKDIR /home/application

RUN /usr/lib/graalvm/bin/gu install native-image
RUN /usr/lib/graalvm/bin/native-image --no-fallback --no-server -jar target/MicronautGraal-0.1.jar -H:Name=micronaut-graal -H:Class=com.example.BookLambdaRuntime
RUN chmod 777 bootstrap
RUN chmod 777 micronaut-graal
RUN zip -j micronaut-graal.zip bootstrap micronaut-graal

EXPOSE 8080
ENTRYPOINT ["/home/application/complete"]

错误本身：

io.micronaut.context.exceptions.DependencyInjectionException: Failed to inject value for field [service] of class: com.example.BookRequestHandler
Message: Error setting field value: No field 'service' found for type: com.example.BookRequestHandler

我确信问题不在代码中，因为它将在整个过程中运行和工作/mvnm插件。我是不是在应用程序构建中遗漏了什么？我通过插件获得的图像比直接通过本机图像获得的图像多500kb。

我真的很感激任何帮助。谢谢

Answer 1

使用应该考虑通过构造函数进行注入，这是GraalVM本地应用程序推荐的方式。

@Introspected
public class BookRequestHandler extends MicronautRequestHandler<Book, BookSaved> {

    private final BookService service;

    @Inject
    public BookRequestHandler(BookService service) {
      this.service = service;
    }

    @Override
    public BookSaved execute(Book input) {
        return service.process(input);
    }
}

Answer 2

在添加注释处理器路径-graal并在继承器中显式声明验证和注入后，问题消失了：

<annotationProcessorPaths>
  <path>
    <groupId>io.micronaut</groupId>
    <artifactId>micronaut-graal</artifactId>
    <version>${micronaut.version}</version>
  </path>
  <path>
    <groupId>io.micronaut</groupId>
    <artifactId>micronaut-inject-java</artifactId>
    <version>${micronaut.version}</version>
  </path>
  <path>
    <groupId>io.micronaut</groupId>
    <artifactId>micronaut-validation</artifactId>
    <version>${micronaut.version}</version>
  </path>
</annotationProcessorPaths>

Answer 3

JVM的一个限制是，我们不能在不使用反射的情况下注入私有字段。

你有两个选择：

1. 将字段包设置为私有而不是私有