Java ClassNotFoundException-在具有maven依赖项的jersey servlet中

我有一个Jersey RESTful服务，它依赖于我的另一个项目。 我已确保部署程序集中存在Maven依赖项库

但是当启动servlet并尝试从依赖项项目访问类时，我得到了

ClassNotFoundException

：

SEVERE: Servlet.service() for servlet [product-crud-servlet] in context with path [/product-crud] threw exception [A MultiException has 2 exceptions.  They are:
1. java.lang.NoClassDefFoundError: com/reaf/db/dao/Dao
2. java.lang.IllegalStateException: Unable to perform operation: create on com.reaf.rest.ProductCRUDService
] with root cause
java.lang.ClassNotFoundException: com.reaf.db.dao.Dao
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1295)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1147)
at com.reaf.rest.ProductCRUDService.<init>(ProductCRUDService.java:25)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.glassfish.hk2.utilities.reflection.ReflectionHelper.makeMe(ReflectionHelper.java:1105)
at org.jvnet.hk2.internal.ClazzCreator.createMe(ClazzCreator.java:292)
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:422)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:456)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:160)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2445)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:621)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:606)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:173)
at org.glassfish.jersey.server.model.MethodHandler$ClassBasedMethodHandler.getInstance(MethodHandler.java:185)
at org.glassfish.jersey.server.internal.routing.PushMethodHandlerRouter.apply(PushMethodHandlerRouter.java:103)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:128)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:131)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:131)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:131)
at org.glassfish.jersey.server.internal.routing.RoutingStage._apply(RoutingStage.java:131)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:110)
at org.glassfish.jersey.server.internal.routing.RoutingStage.apply(RoutingStage.java:65)
at org.glassfish.jersey.process.internal.Stages.process(Stages.java:197)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:250)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:320)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1028)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:373)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:381)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:344)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:219)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

我的Servlet类当前如下所示：

public class ProductCRUDService extends MyResourceConfig {

    public ProductCRUDService() {
        resourceConfig.register(JacksonJsonProvider.class);
        resourceConfig.register(Dao.class); // this class causes the Exception
        System.out.println(com.reaf.db.dao.Dao.class);
    }
}

MyResourceConfig

只是：

public class MyResourceConfig {
    public static final ResourceConfig resourceConfig = new ResourceConfig();
}

---

NB：当运行JUnit测试用例时，我可以访问我的类而不出现任何问题。

Subject Jersey，堆栈跟踪中还有其他类。请更正。显然，包含您的

Dao

类的jar在WEB应用程序的WEB-INF/lib中不可用。我猜这会发生在您的IDE中，因此您应该确保您拥有将Maven与Web应用程序集成的所有必要工具。在Eclipse中，这些被称为

public class MyResourceConfig {
    public static final ResourceConfig resourceConfig = new ResourceConfig();
}