Micronaut 中是否有 Springs Resource 的等效项？

Question

我正在将一个微型 Spring 引导应用程序迁移到 Micronaut 1.0.1，我想知道是否有 org.springframework.core.io.Resource 的等效项及其实现，例如 ClasspathResource？

在 Spring 引导中，我使用其构造函数将资源注入到服务中。

@Service
public class MyService() {

    private final Resource resource;

    public MyService(Resource resource) { this.resource = resource; }
}

如何在 Micronaut 中执行此操作？

@Singleton
public class MyService() {

    private final Resource resource;

    @Inject
    public MyService(Resource resource) { this.resource = resource; }
}

Answer 1

在 Micronaut 中，您可以使用 io.micronaut.core.io.ResourceLoader 变体，例如 io.micronaut.core.io.scan.ClassPathResourceLoader 或 io.micronaut.core.io.file.FileSystemResourceLoader。获取它们的一种选择是通过 io.micronaut.core.io.ResourceResolver:

ClassPathResourceLoader loader = new ResourceResolver().getLoader(ClassPathResourceLoader.class).get();
Optional<URL> resource = loader.getResource("classpath:foo/bar.txt");

Answer 2

我用了io.micronaut.core.io.ResourceLoader。通过构造函数连接：

@Controller("root")
public class MyController {

    private final ResourceLoader loader;

    public MyController(ResourceLoader loader) {
        this.loader = loader;
    }

    @Get("/index")
    @Produces(MediaType.TEXT_HTML)
    public String greet() throws IOException {
        return new String(loader.getResourceAsStream("index.html").get().readAllBytes());
    }
}

我的 index.html 路径：src/main/resources/index.html

Answer 3

ResourceLoader works well but you can do better. In Micronaut you can use io.micronaut.core.io.Readable. It is roughly equivalent to Spring's Resource. You can also use Readable in ConfigurationProperties 从而将您的配置 yaml/properties 直接绑定到 Readable 属性：

micronaut:
  application:
    name: Demo
images:
  image-file: "classpath:images/bismarckia-nobilis.jpg"
  # image-file: "file:/path/to/images/bismarckia-nobilis.jpg"
  other-files:
    - "classpath:images/bismarckia-nobilis.jpg"
    - "classpath:images/bamboo.jpg"
    - "classpath:images/hibiscus.jpg"

我创建了：

博客post：https://hillert.com/blog/from-resource-to-readable/
演示：https://github.com/ghillert/resource-readable-demo

Answer 4

你可以这样做

@Singleton
public class MyService {

    @Value("classpath:your-file.json")
    private Readable readable;
}

或

@Singleton
public class MyService {

    private final Readable readable;

    public MyService(@Value("classpath:your-file.json") Readable file) {
        this.readable = readable;
    }
}

Micronaut 中是否有 Springs Resource 的等效项？

Is there an equivalent for Springs Resource in Micronaut?

java

micronaut