java - 将 Spring 属性占位符与 Jersey @Path 和 @ApplicationPath 一起使用

Question

我在项目中使用 Jersey 和 Spring。 'jersey-spring3' 用于它们之间的集成。我想让我的资源类更加灵活，并在 @Path 注释中使用属性，例如:

@Path("${some.property}/abc/def")

但是Spring不能给Jersey的注解@Path和@ApplicationPath注入(inject)some.property。

有没有什么方法可以在 Jersey 资源的 @Path 值中设置一些可配置的(使用属性文件)值？

(我意识到用 Spring MVC 替换 Jersey 会更容易，但不幸的是，就我而言，我没有这个选择。)

Answer 1

所以这是答案的一半(或者可能是完整答案，具体取决于解析 @ApplicationPath 对您的重要性)。

要理解下面的解决方案，您应该首先了解一些 Jersey 的内部结构。当我们加载应用程序时，Jersey 会构建所有资源的模型。资源的所有信息都封装在这个模型中。 Jersey 使用这个模型来处理请求，而不是尝试在每个请求上处理资源，将有关资源的所有信息保存在模型中并处理模型会更快。

有了这个架构，Jersey 还允许我们 build resources programmatically ，使用它在内部使用的相同 API 来保存模型属性。除了构建资源模型，我们还可以modify existing models , 使用 ModelProcessor

在 ModelProcessor 中，我们可以注入(inject) Spring 的 PropertyResolver，然后以编程方式解析占位符，并用已解析的路径替换旧的资源模型路径。例如

@Autowired
private PropertyResolver propertyResolver;

private ResourceModel processResourceModel(ResourceModel resourceModel) {
    ResourceModel.Builder newResourceModelBuilder = new ResourceModel.Builder(false);
    for (final Resource resource : resourceModel.getResources()) {
        final Resource.Builder resourceBuilder = Resource.builder(resource);
        String resolvedResourcePath = processPropertyPlaceholder(resource);
        resourceBuilder.path(resolvedResourcePath);

        // handle child resources
        for (Resource childResource : resource.getChildResources()) {
            String resolvedChildPath = processPropertyPlaceholder(childResource);
            final Resource.Builder childResourceBuilder = Resource.builder(childResource);
            childResourceBuilder.path(resolvedChildPath);
                resourceBuilder.addChildResource(childResourceBuilder.build());
        }
        newResourceModelBuilder.addResource(resourceBuilder.build());
    }
    return newResourceModelBuilder.build();
}

private String processPropertyPlaceholder(Resource resource) {
    String ogPath = resource.getPath();
    return propertyResolver.resolvePlaceholders(ogPath);
}

就资源模型API而言

• 这是一个资源

  @Path("resource")
  public class SomeResource {
      @GET
      public String get() {}
  }
  

  不用@Path注解的资源方法是ResourceMethod

• 这是上述 Resource 的 child Resource 因为它用 @Path 注释.

  @GET
  @Path("child-resource")
  public String get() {}
  

这些信息应该能让您对上述实现的工作原理有所了解。

下面是一个完整的测试，使用Jersey Test Framework .使用了以下类路径属性文件

app.properties

resource=resource
sub.resource=sub-resource
sub.resource.locator=sub-resource-locator

您可以像运行任何其他 JUnit 测试一样运行以下内容。

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;

import org.glassfish.jersey.filter.LoggingFilter;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.server.model.ModelProcessor;
import org.glassfish.jersey.server.model.Resource;
import org.glassfish.jersey.server.model.ResourceModel;
import org.glassfish.jersey.test.JerseyTest;
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.PropertyResolver;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

/**
 * Stack Overflow http://stackoverflow.com/q/34943650/2587435
 * 
 * Run it like any other JUnit test. Required dependencies are as follows:
 * 
 * <dependency>
 *     <groupId>org.glassfish.jersey.test-framework.providers</groupId>
 *     <artifactId>jersey-test-framework-provider-grizzly2</artifactId>
 *     <version>2.22.1</version>
 *     <scope>test</scope>
 * </dependency>
 * <dependency>
 *     <groupId>org.glassfish.jersey.ext</groupId>
 *     <artifactId>jersey-spring3</artifactId>
 *     <version>2.22.1</version>
 *     <scope>test</scope>
 * </dependency>
 * <dependency>
 *     <groupId>commons-logging</groupId>
 *     <artifactId>commons-logging</artifactId>
 *     <version>1.1</version>
 *     <scope>test</scope>
 * </dependency>
 * 
 * @author Paul Samsotha
 */
public class SpringPathResolverTest extends JerseyTest {

    @Path("${resource}")
    public static class TestResource {

        @GET
        public String get() {
            return "Resource Success!";
        }

        @GET
        @Path("${sub.resource}")
        public String getSubMethod() {
            return "Sub-Resource Success!";
        }

        @Path("${sub.resource.locator}")
        public SubResourceLocator getSubResourceLocator() {
            return new SubResourceLocator();
        }

        public static class SubResourceLocator {

            @GET
            public String get() {
                return "Sub-Resource-Locator Success!";
            }
        }
    }

    @Configuration
    @PropertySource("classpath:/app.properties")
    public static class SpringConfig {
    }

    public static class PropertyPlaceholderPathResolvingModelProcessor
            implements ModelProcessor {

        @Autowired
        private PropertyResolver propertyResolver;

        @Override
        public ResourceModel processResourceModel(ResourceModel resourceModel,
                javax.ws.rs.core.Configuration configuration) {
            return processResourceModel(resourceModel);
        }

        @Override
        public ResourceModel processSubResource(ResourceModel subResourceModel,
                javax.ws.rs.core.Configuration configuration) {
            return subResourceModel;
        }

        private ResourceModel processResourceModel(ResourceModel resourceModel) {
            ResourceModel.Builder newResourceModelBuilder = new ResourceModel.Builder(false);
            for (final Resource resource : resourceModel.getResources()) {
                final Resource.Builder resourceBuilder = Resource.builder(resource);
                String resolvedResourcePath = processPropertyPlaceholder(resource);
                resourceBuilder.path(resolvedResourcePath);

                // handle child resources
                for (Resource childResource : resource.getChildResources()) {
                    String resolvedChildPath = processPropertyPlaceholder(childResource);
                    final Resource.Builder childResourceBuilder = Resource.builder(childResource);
                    childResourceBuilder.path(resolvedChildPath);
                    resourceBuilder.addChildResource(childResourceBuilder.build());
                }
                newResourceModelBuilder.addResource(resourceBuilder.build());
            }
            return newResourceModelBuilder.build();
        }

        private String processPropertyPlaceholder(Resource resource) {
            String ogPath = resource.getPath();
            return propertyResolver.resolvePlaceholders(ogPath);
        }
    }

    @Override
    public ResourceConfig configure() {
        ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
        return new ResourceConfig(TestResource.class)
                .property("contextConfig", ctx)
                .register(PropertyPlaceholderPathResolvingModelProcessor.class)
                .register(new LoggingFilter(Logger.getAnonymousLogger(), true));
    }

    @Test
    public void pathPlaceholderShouldBeResolved() {
        Response response = target("resource").request().get();
        assertThat(response.getStatus(), is(200));
        assertThat(response.readEntity(String.class), is(equalTo("Resource Success!")));
        response.close();

        response = target("resource/sub-resource").request().get();
        assertThat(response.getStatus(), is(200));
        assertThat(response.readEntity(String.class), is(equalTo("Sub-Resource Success!")));
        response.close();

        response = target("resource/sub-resource-locator").request().get();
        assertThat(response.getStatus(), is(200));
        assertThat(response.readEntity(String.class), is(equalTo("Sub-Resource-Locator Success!")));
        response.close();
    }
}

而且现在我想到了，我可以看到一种使用解析 @ApplicationPath 的方法，但它涉及创建 Jersey servlet 容器以编程方式在 Spring WebAppInitializer 中。老实说，我认为这会比它的值(value)更麻烦。我只是接受它，并将 @ApplicationPath 保留为静态字符串。

---

更新

如果您使用的是 Spring boot，那么应用程序路径绝对是可配置的，通过 spring.jersey.applicationPath 属性。 Spring boot 加载 Jersey 的方式几乎就是我在上一段中想到的想法，您自己在其中创建 Jersey servlet 容器，并设置 servlet 映射。这就是使用 Spring Boot 进行配置的方式。