Gogo Shell命令消失，如果我引用服务

Question

源代码

在我的模块中，我编写了这个Liferay服务：

package jp.co.my.module;
import com.liferay.portal.kernel.exception.PortalException;
import com.liferay.portal.kernel.module.framework.service.IdentifiableOSGiService;
import com.liferay.portal.kernel.service.BaseLocalServiceImpl;
public class TestService extends BaseLocalServiceImpl
implements IdentifiableOSGiService {
public void test() throws PortalException {
System.out.println("In the future I will do stuff here");
}
@Override
public String getOSGiServiceIdentifier() {
return TestService.class.getName();
}
}

在同一模块中，我编写了一个使用该服务的命令：

package jp.co.my.module;
import com.liferay.portal.kernel.exception.PortalException;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
@Component(
property = {
"osgi.command.function=test",
"osgi.command.scope=liferay"
},
service = Object.class)
public class TestCommand {
public void test() throws PortalException {
System.out.println("In the future I will call the service here");
}
@Reference private volatile TestService _testService;
}

问题

模块部署正确，但在 Gogo Shell 中该命令不可用：

g! test
gogo: CommandNotFoundException: Command not found: test
g! b 1001
jp.co.my.module_1.0.0 [1001]
Id=1001, Status=ACTIVE      Data Root=/home/nico/liferay/osgi/state/org.eclipse.osgi/1001/data                                               
"No registered services."
Services in use:
{org.osgi.service.log.LogService, org.eclipse.equinox.log.ExtendedLogService}={service.id=2, service.bundleid=0, service.scope=bundle}             
No exported packages
Imported packages
com.liferay.portal.kernel.exception; version="7.1.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>                                                
com.liferay.portal.kernel.module.framework.service; version="1.0.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>                                 
com.liferay.portal.kernel.service; version="1.27.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>                                                 
No fragment bundles
No required bundles

但！如果我从TestCommand.java中删除@Reference private volatile TestService _testService;，它可以完美运行：

g! test
In the future I will call the service here
g! b 1005
jp.co.my.module_1.0.0 [1005]
Id=1005, Status=ACTIVE      Data Root=/home/nico/liferay/osgi/state/org.eclipse.osgi/1005/data
"Registered Services"
{java.lang.Object}={osgi.command.function=test, component.name=jp.co.my.module.TestCommand, component.id=2740, osgi.command.scope=liferay, service.id=7652, service.bundleid=1005, service.scope=bundle}
Services in use:
{org.osgi.service.log.LogService, org.eclipse.equinox.log.ExtendedLogService}={service.id=2, service.bundleid=0, service.scope=bundle}
No exported packages
Imported packages
com.liferay.portal.kernel.exception; version="7.1.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>
com.liferay.portal.kernel.module.framework.service; version="1.0.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>
com.liferay.portal.kernel.service; version="1.27.0" <org.eclipse.osgi_3.10.200.v20150831-0856 [0]>
No fragment bundles
No required bundles

问：这是为什么？如何正确引用服务？

Answer 1

我没有使用过liferay，但它似乎非常接近OSGI的概念。您的 TestCommand 是一个依赖于 TestService 的组件，因为您已经使用了@Reference。这意味着TestService也是一个组件。但是您还没有在任何地方将TestService定义为组件。

我有根据的猜测是TestService也必须使用@Component，所以liferay会知道它是一个组件，创建它，并将其注入TestCommand：

@Component
public class TestService extends BaseLocalServiceImpl
implements IdentifiableOSGiService {

我不知道尝试在没有定义的 java 接口的情况下创建和引用组件可能会有其他问题。

编辑：我的回答反映了这里的一些信息。 https://portal.liferay.dev/docs/7-0/tutorials/-/knowledge_base/t/osgi-and-modularity-for-liferay-6-developers#osgi-services-and-dependency-injection-with-declarative-services

EDIT2：它没有该行完美运行的原因是删除@Reference删除了TestCommand和TestService之间断开的依赖链接。有了这条线，依赖链就在那里但未解析，所以你的TestCommand不会启动

编辑3：

@Component(
configurationPid = "jp.co.my.module",
immediate = true,
property = {}, 
service = TestService.class
)