动态注册资源的Jersey web应用程序

Question

我有一个web应用程序，它将从jar文件动态加载其资源。

我必须如何重新编写加载和注册资源并启动服务器的主类，以便它在web应用程序内部工作？

我目前定义了一个javax.ws.rs.core.application，它在标记为@PostConstruct的方法中加载资源。虽然这是有效的，但它会随着每个请求初始化。

我尝试将javax.inject.singleton添加到应用程序中，但这导致了错误：

java.lang.IllegalStateException: Unable to perform operation: post construct on com.test.server.IntegrationServer
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:392)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:471)
at org.jvnet.hk2.internal.SingletonContext$1.compute(SingletonContext.java:83)
at org.jvnet.hk2.internal.SingletonContext$1.compute(SingletonContext.java:71)
at org.glassfish.hk2.utilities.cache.Cache$OriginThreadAwareFuture$1.call(Cache.java:97)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at org.glassfish.hk2.utilities.cache.Cache$OriginThreadAwareFuture.run(Cache.java:154)
at org.glassfish.hk2.utilities.cache.Cache.compute(Cache.java:199)
at org.jvnet.hk2.internal.SingletonContext.findOrCreate(SingletonContext.java:122)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2020)
at org.jvnet.hk2.internal.ServiceLocatorImpl.internalGetService(ServiceLocatorImpl.java:766)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:705)
at org.glassfish.jersey.server.ApplicationHandler.createApplication(ApplicationHandler.java:385)
at org.glassfish.jersey.server.ApplicationHandler.<init>(ApplicationHandler.java:342)
at org.glassfish.jersey.servlet.WebComponent.<init>(WebComponent.java:392)
at org.glassfish.jersey.servlet.ServletContainer.init(ServletContainer.java:177)
at org.glassfish.jersey.servlet.ServletContainer.init(ServletContainer.java:369)
at javax.servlet.GenericServlet.init(GenericServlet.java:158)

我的做法是完全错误的吗？或者如何创建这样一个系统，作为可部署的war运行？

*编辑*

通过使用ServletContextListener，我可以解决多个init调用，但我的资源没有加载。

@Path("test")

应用程序现在加载这个文件位置，并通过ServiceLoader加载所有MarkerInterface类并将它们注册。

我有

@WebListener
public class IntegrationServer extends ResourceConfig implements ServletContextListener {

@Override
public void contextInitialized(ServletContextEvent sce) {
    LOGGER.info(() -> "CONTEXT INIT");
    try {
        register(JacksonFeature.class);
        // wrapper for the ServiceLoader implementation
        this.serviceLoader = new IntegrationServiceLoader();
       this.serviceLoader.loadIntegrations(MarkerInterface.class, gce -> {
            LOGGER.info(() -> "Adding " + gce.getClass() + " to Server");
            register(gce.getClass());
        });
    }
    catch (IOException e) {
        LOGGER.log(Level.SEVERE, e, () -> "Failed to init integration server");
    }
}

}

当在tomcat上将其部署为server.war时，我在日志中看到了注册输出，但当我调用HTTP://localhost:8080/server/test/get时，我得到了HTTP状态404-未找到。

我的web.xml看起来像

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<servlet>
    <servlet-name>Jersey Web Application</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>Jersey Web Application</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

**编辑2***

关于这个讨论，请参阅CássioMazzochiMolin的答案。

Builder{names=[com.test.server.TestResource], path='backend', methodBuilders=[], childResourceBuilders=[Builder{names=[[unnamed]], path='info', methodBuilders=[org.glassfish.jersey.server.model.ResourceMethod$Builder@819f71f], childResourceBuilders=[], childResources=[], resourceMethods=[], subResourceLocator=null, handlerClasses=[], handlerInstances=[], parentResource=Builder{names=[com.cetrea.qa.server.TestResource], path='backend'}, extended=false}], childResources=[Resource{"achievements", 3 child resources, 0 resource methods, 0 sub-resource locator, 1 method handler classes, 0 method handler instances},

Answer 1

Jersey提供了一个API用于以编程方式构建资源。

根据文档，resource类是编程资源建模API的主要入口点，该API提供了以编程方式扩展现有JAX-RS注释资源类或构建Jersey运行时可能使用的新资源模型的能力。

请查看文档提供的示例：

@Path("hello")
public class HelloResource {

     @GET
     @Produces("text/plain")
     public String sayHello() {
         return "Hello!";
     }
}

// Register the annotated resource.
ResourceConfig resourceConfig = new ResourceConfig(HelloResource.class);

// Add new "hello2" resource using the annotated resource class
// and overriding the resource path.
Resource.Builder resourceBuilder =
        Resource.builder(HelloResource.class, new LinkedList<ResourceModelIssue>())
        .path("hello2");

// Add a new (virtual) sub-resource method to the "hello2" resource.
resourceBuilder.addChildResource("world").addMethod("GET")
        .produces("text/plain")
        .handledBy(new Inflector<Request, String>() {
                @Override
                public String apply(Request request) {
                    return "Hello World!";
                }
        });

// Register the new programmatic resource in the application's configuration.
resourceConfig.registerResources(resourceBuilder.build());

下表说明了上面示例中配置的应用程序所支持的请求和提供的响应：

 Request              |  Response        |  Method invoked
----------------------+------------------+--------------------------
 GET /hello           | "Hello!"         | HelloResource.sayHello()
 GET /hello2          | "Hello!"         | HelloResource.sayHello()
 GET /hello2/world    | "Hello World!"   | Inflector.apply()

要了解更多细节，请查看泽西文件。