我正在尝试在Jersey / Hk2应用程序中注入EntityManagerFactory(作为Singleton)和EntityManager(在请求范围内)。
我正在使用这个问题(How to i properly configure an entitymanager in a jersey-hk2 application)作为指导
我花了一天的时间试图使其运行，但我有很多例外。我不知道错误在哪里。
WARNING: Unknown HK2 failure detected:
MultiException stack 1 of 3
org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object
available for injection at SystemInjecteeImpl(requiredType=EntityManagerFactory,parent=EntityManagerProvider...)
...
While attempting to resolve the dependencies of mypackages.EntityManagerProvider errors were found
...
java.lang.IllegalStateException: Unable to perform operation: resolve on mypackages.EntityManagerProvider
...
There was no object available for injection at SystemInjecteeImpl(requiredType=EntityManagerFactory,parent=EntityManagerProvider...
...
java.lang.IllegalArgumentException: While attempting to resolve the dependencies of mypackages.EntityManagerProvider errors were found
...
java.lang.IllegalStateException: Unable to perform operation: resolve on mypackages.EntityManagerProvider
还有很多我削减的例外
这是我的代码:
我的EntityManagerFactoryProvider(Singleton):
public class EntityManagerFactoryProvider implements Factory<EntityManagerFactory> {
private static final String PERSISTENT_UNIT = "test";
private final EntityManagerFactory emf;
public EntityManagerFactoryProvider(@Named(PERSISTENT_UNIT) String persistentUnit) {
emf = Persistence.createEntityManagerFactory(persistentUnit);
}
@Override
public EntityManagerFactory provide() {
return emf;
}
@Override
public void dispose(EntityManagerFactory instance) {
instance.close();
}
}
我的EntityManagerProvider(每个请求)是:
public class EntityManagerProvider implements Factory<EntityManager> {
private final EntityManagerFactory emf;
private final CloseableService closeableService;
@Inject
public EntityManagerProvider(EntityManagerFactory emf, CloseableService closeableService) {
this.emf = emf;
this.closeableService = closeableService;
}
@Override
public EntityManager provide() {
final EntityManager em = emf.createEntityManager();
this.closeableService.add(new Closeable() {
@Override
public void close() throws IOException {
em.close();
}
});
return em;
}
@Override
public void dispose(EntityManager entityManager) {
if (entityManager.isOpen()) {
entityManager.close();
}
}
}
MyApplication是:
public class MyApplication extends ResourceConfig {
public MyApplication() {
register(new MyApplicationBinder());
packages(true, "mypackages");
}
}
MyApplicationBinder是:
public class MyApplicationBinder extends AbstractBinder {
@Override
protected void configure() {
bindFactory(EntityManagerFactoryProvider.class)
.to(EntityManagerFactory.class)
.in(Singleton.class);
bindFactory(EntityManagerProvider.class)
.to(EntityManager.class)
.in(RequestScoped.class);
}
}
我的资源是:
@Path("myresource")
public class MyResource {
@Inject
EntityManager em;
/**
* Method handling HTTP GET requests. The returned object will be sent
* to the client as "text/plain" media type.
*
* @return String that will be returned as a text/plain response.
*/
@GET
@Produces(MediaType.TEXT_PLAIN)
public String getIt() {
return "Got it!";
}
}
和Web.xml
<?xml version="1.0" encoding="UTF-8"?>
<!-- This web.xml file is not required when using Servlet 3.0 container,
see implementation details
http://jersey.java.net/nonav/documentation/latest/jax-rs.html -->
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>MyApplication</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-
class>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>mypackage.MyApplication</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MyApplication</servlet-name>
<url-pattern>/webapi/*</url-pattern>
</servlet-mapping>
</web-app>
非常感谢
最佳答案
我认为您没有显示完整的stacktrace。在测试时，我确实看到了帖子中显示的那部分跟踪，但这只是跟踪的一部分。主要原因是
java.lang.NoSuchMethodException:在EntityManagerFactoryProvider中找不到合适的构造函数
查看您的EntityManagerFactoryProvider构造函数。
public EntityManagerFactoryProvider(@Named(PERSISTENT_UNIT) String persistentUnit) {
emf = Persistence.createEntityManagerFactory(persistentUnit);
}
persistentUnit应该来自哪里。您需要将其连接到活页夹中。而且@Named也没有定义注入点。它只是注入点的支持注释。就像在@Inject构造函数上一样，在创建EntityManagerProvider时创建的注入点。因此，请修复两件事:
bind(persistenceUnitName).to(String.class).named(PERSISTENT_UNIT);
@Inject批注创建注入点@Inject
public EntityManagerFactoryProvider(@Named(PERSISTENT_UNIT) String persistentUnit) {
emf = Persistence.createEntityManagerFactory(persistentUnit);
}