在普通Java编程中使用Quarkus Panache实体时出错

Question

我正在尝试为我的Panache实体创建一个非常知名的泛型资源，但是，它似乎无法与Java泛型很好地配合。我想要做的是避免重复常见的REST操作。我想更改HTTP元信息（例如：是否进行身份验证，资源路径等），但是所有时候实际的响应构建都是相同的，所以我构建了这个通用类：

package org.reproducer;

import java.net.URI;
import java.util.List;

import javax.transaction.Transactional;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriBuilder;

import io.quarkus.hibernate.orm.panache.PanacheEntity;

public class BaseResource<T extends PanacheEntity> {

    public List<T> listAll() {
        return T.listAll();
    }

    public Response get(long id) {
        T entity = T.findById(id);
        if (entity != null) {
            return Response.ok(entity).build();
        } else {
            return notFound(id);
        }
    }

    @Transactional
    public Response add(T entity) {
        T.persist(entity);
        URI uri = UriBuilder.fromPath("/")
                // "this" reference was not working here
                .path(entity.getClass().getName().toLowerCase()).path("{id}").build(entity.id);
        return Response.created(uri).build();
    }

    @Transactional
    public Response remove(long id) {
        T entity = T.findById(id);
        if (entity != null) {
            entity.delete();
            return Response.noContent().build();
        } else {
            return notFound(id);
        }
    }

    private Response notFound(long id) {
        return Response.status(404).entity("Entity with id " + id + " not found.").build();
    }

}

因此，我可以扩展并专注于资源中的REST / HTTP部分：

import java.util.List;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.reproducer.model.TheEntity;

@Path("/entity2")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public class ResourceWithBase extends BaseResource<TheEntity>{

    @GET
    public List<TheEntity> listAll() {
        return super.listAll();
    }

    @GET
    @Path("{id}")
    public Response get(@PathParam("id") long id) {
        return super.get(id);
    }

    @POST
    public Response add(TheEntity entity) {
        return super.add(entity);
    }

    @DELETE
    @Path("{id}")
    public Response remove(@PathParam("id") long id) {
        return super.remove(id);
    }

}

但是，无论我尝试调用哪种方法，都会失败：

但是，无论我尝试调用哪种方法，它都会因This method is normally automatically overridden in subclasses: did you forget to annotate your entity with @Entity?而失败（下面是完整的堆栈跟踪

ERROR: Exception handling request fcc704b2-25f9-4fac-b60e-3dd1f25a7c7c-1 to /entity2
org.jboss.resteasy.spi.UnhandledException: java.lang.IllegalStateException: This method is normally automatically overridden in subclasses: did you forget to annotate your entity with @Entity?
    at org.jboss.resteasy.core.ExceptionHandler.handleApplicationException(ExceptionHandler.java:106)
    at org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:372)
    at org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:209)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:496)
    at org.jboss.resteasy.core.SynchronousDispatcher.lambda$invoke$4(SynchronousDispatcher.java:252)
    at org.jboss.resteasy.core.SynchronousDispatcher.lambda$preprocess$0(SynchronousDispatcher.java:153)
    at org.jboss.resteasy.core.interception.jaxrs.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:363)
    at org.jboss.resteasy.core.SynchronousDispatcher.preprocess(SynchronousDispatcher.java:156)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:238)
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:249)
    at io.quarkus.resteasy.runtime.ResteasyFilter$ResteasyResponseWrapper.sendError(ResteasyFilter.java:64)
    at io.undertow.servlet.handlers.DefaultServlet.doGet(DefaultServlet.java:175)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:686)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:791)
    at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
    at io.quarkus.resteasy.runtime.ResteasyFilter.doFilter(ResteasyFilter.java:28)
    at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
    at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
    at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
    at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
    at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
    at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
    at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
    at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
    at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
    at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
    at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
    at io.quarkus.undertow.runtime.UndertowDeploymentRecorder$8$1$1.call(UndertowDeploymentRecorder.java:489)
    at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
    at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
    at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
    at io.undertow.server.Connectors.executeRootHandler(Connectors.java:364)
    at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830)
    at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
    at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2011)
    at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1535)
    at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1395)
    at org.jboss.threads.DelegatingRunnable.run(DelegatingRunnable.java:29)
    at org.jboss.threads.ThreadLocalResettingRunnable.run(ThreadLocalResettingRunnable.java:29)
    at java.lang.Thread.run(Thread.java:748)
    at org.jboss.threads.JBossThread.run(JBossThread.java:479)
Caused by: java.lang.IllegalStateException: This method is normally automatically overridden in subclasses: did you forget to annotate your entity with @Entity?
    at io.quarkus.hibernate.orm.panache.runtime.JpaOperations.implementationInjectionMissing(JpaOperations.java:351)
    at io.quarkus.hibernate.orm.panache.PanacheEntityBase.listAll(PanacheEntityBase.java:355)
    at org.reproducer.BaseResource.listAll(BaseResource.java:15)
    at org.reproducer.ResourceWithBase.listAll(ResourceWithBase.java:24)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:151)
    at org.jboss.resteasy.core.MethodInjectorImpl.lambda$invoke$3(MethodInjectorImpl.java:122)
    at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:602)
    at java.util.concurrent.CompletableFuture.uniApplyStage(CompletableFuture.java:614)
    at java.util.concurrent.CompletableFuture.thenApply(CompletableFuture.java:1983)
    at java.util.concurrent.CompletableFuture.thenApply(CompletableFuture.java:110)
    at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:122)
    at org.jboss.resteasy.core.ResourceMethodInvoker.internalInvokeOnTarget(ResourceMethodInvoker.java:580)
    at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTargetAfterFilter(ResourceMethodInvoker.java:454)
    at org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invokeOnTarget$2(ResourceMethodInvoker.java:408)
    at org.jboss.resteasy.core.interception.jaxrs.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:363)
    at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:410)
    at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:379)
    at org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invoke$1(ResourceMethodInvoker.java:353)
    at java.util.concurrent.CompletableFuture.uniComposeStage(CompletableFuture.java:981)
    at java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:2124)
    at java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:110)
    at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:353)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:477)
    ... 49 more

我尝试了不同的方法，例如使用存储库，定义方法的接口和其他方法。总是以不同的方式失败，似乎Panache不喜欢泛型或panache扩展未实现为T生成代码的方法。{some panache static method}！

这是预期的吗？您是否建议采取任何解决方法以使其正常工作？

复制者的代码可以在这里找到-> https://github.com/jesuino/reproducers/tree/master/quarkus-panache-generics

我讨厌为此重复代码！

Answer 1

我在此处复制/粘贴我在Github问题上所做的回答

您要执行的操作无法正常工作，这不是Panache的限制，而是Java泛型的工作方式。

在您的复制人上，我看到了：

mtcars %>%
    mutate(comb = paste0(substr(as.character(mpg), 1, 2), "_", as.character(cyl)))

} }

即使public class BaseResource<T extends PanacheEntity> { public List<T> listAll() { return T.listAll(); } } public class ResourceWithBase extends BaseResource<TheEntity>{ @GET public List<TheEntity> listAll() { return super.listAll(); 似乎是T类型，在运行时也并非如此，因为T扩展了PancheEntity，运行时类为TheEntity，因此您尝试调用{{ PanacheEntity上的1}}方法，它不起作用。

这是静态方法对Java中的泛型类型起作用的方式。

用另一种方式说：您在T而不是在TheEntity上调用listAll（），因为listAll（）是静态方法，因此它链接到类型而不是实例。