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4
在我的用例中，我需要开发一个自定义注释，通过它我可以实例化 DAO 的实现。
所以我有界面:
public interface IDAO{
public void method1();
public void method2();
}
以及资源配置实现:
public class JAXRSConfig extends ResourceConfig {
public JAXRSConfig() {
register(new AbstractBinder() {
@Override
protected void configure() {
/*Factory Classes Binding*/
bindFactory(DaoFactory.class).to(IDAO.class).in(RequestScoped.class);
/*Injection Resolver Binding*/
bind(CustomContextInjectionResolver.class).to(new TypeLiteral<InjectionResolver<CustomContext>>(){}).in(Singleton.class);
}
});
}
我坚持工厂实现:
public class DaoFactory implements Factory<IDAO>{
private final HttpServletRequest request;
@Inject
public DaoFactory(HttpServletRequest request) {
this.request = request;
}
@Override
public IDAO provide() {
IDAO dao = null;
try {
???????????
} catch (InstantiationException | IllegalAccessException e) {
e.printStackTrace();
}
return dao;
}
@Override
public void dispose( IDAO mud) {
}
}
当然，这里我有我的 IDAO 实现:
public class DAOImplementation implements IDAO {
public void method1(){
//do some stuff
}
public void method2(){
//do some stuff
}
public MyEntity getEntity(){
//get my entity
}
}
我想要得到的结果是:
@Path("/myResource")
public class myService(){
@CustomContext
DAOImplementation myDao;
public String myService(){
MyEntity entity = myDao.getEntity();
}
}
有没有一种方法可以将工厂连接到注入(inject)解析器，就像我可以获得真正的实现一样？ hk2 是否提供任何方法来做到这一点？
已编辑我可以有 IDAO 接口(interface)的多个实现...例如，如果我有:
public class DAOImplementation2 implements IDAO {
public void method1(){
//do some stuff
}
public void method2(){
//do some stuff
}
public MyEntity2 getEntity2(){
//get my entity
}
}
我应该能够得到这样的第二个实现:
@Path("/myResource")
public class myService(){
@CustomContext
DAOImplementation myDao;
@CustomContext
DAOImplementation2 mySecondDao;
public String myService(){
MyEntity entity = myDao.getEntity();
MyEntity2 entity = mySecondDao.getEntity2();
}
}
最佳答案
根据我们之前的聊天，以下是我试图传达的想法。基本上，您将添加一个Feature，用户可以将IDao 实现类传递到其中。在功能中，您可以按名称绑定(bind)它们
public static class DaoFeature implements Feature {
private final Class<? extends IDao>[] daoClasses;
public DaoFeature(Class<? extends IDao> ... daoClasses) {
this.daoClasses = daoClasses;
}
@Override
public boolean configure(FeatureContext context) {
context.register(new Binder());
return true;
}
private class Binder extends AbstractBinder {
@Override
protected void configure() {
...
for (Class<? extends IDao> daoClass: daoClasses) {
bind(daoClass).to(IDao.class)
.named(daoClass.getCanonicalName()).in(RequestScoped.class);
}
}
}
}
然后在 InjectionResolver 中，您可以按名称查找并将其添加到 CloseableService 中。所有这些都不需要任何丑陋的反射。
public static class CustomContextResolver
implements InjectionResolver<CustomContext> {
@Inject
private ServiceLocator locator;
@Inject
private IDaoProviders daoClasses;
@Inject
private CloseableService closeableService;
@Override
public Object resolve(Injectee injectee, ServiceHandle<?> root) {
Type requiredType = injectee.getRequiredType();
for (Class type: daoClasses.getDaoClasses()) {
if (requiredType == type) {
IDao dao = locator.getService(IDao.class, type.getCanonicalName());
addToCloseableService(dao);
return type.cast(dao);
}
}
return null;
}
...
}
EntityManager 将由 Factory 处理。我使用的 Factory 是一个 Jersey 类，它可以让您获取 ContainerRequest ，您几乎可以从 HttpServletRequest 中获取任何内容>
public static class DummyEntityManagerFactory
extends AbstractContainerRequestValueFactory<DummyEntityManager> {
@Override
public DummyEntityManager provide() {
ContainerRequest request = getContainerRequest();
// get some condition for EntityManager
return new DummyEntityManager();
}
}
在抽象IDao类中，您可以注入(inject)EntityManager，并自行处理和处置资源。
public static abstract class IDao {
@Inject
private DummyEntityManager em;
protected abstract String getData();
public void close() {
em.close();
}
protected DummyEntityManager getEntityManager() {
return em;
}
}
这是完整的测试用例
import java.io.Closeable;
import java.io.IOException;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.core.Response;
import org.glassfish.hk2.api.Injectee;
import org.glassfish.hk2.api.InjectionResolver;
import org.glassfish.hk2.api.ServiceHandle;
import org.glassfish.hk2.api.ServiceLocator;
import org.glassfish.hk2.api.TypeLiteral;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
import org.glassfish.jersey.process.internal.RequestScoped;
import org.glassfish.jersey.server.CloseableService;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.ResourceConfig;
import org.glassfish.jersey.server.internal.inject.AbstractContainerRequestValueFactory;
import org.glassfish.jersey.test.JerseyTest;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class CustomDaoTest extends JerseyTest {
public static class DummyEntityManager {
String findByDaoClass(Class cls) {
return "Data from " + cls.getSimpleName();
}
public void close() { /* noop */ }
}
public static abstract class IDao {
private static final Logger LOG = Logger.getLogger(IDao.class.getName());
@Inject
private DummyEntityManager em;
protected abstract String getData();
public void close() {
LOG.log(Level.INFO, "Closing IDAO: {0}", this.getClass().getName());
em.close();
}
protected DummyEntityManager getEntityManager() {
return em;
}
}
public static class DaoImplOne extends IDao {
@Override
public String getData() {
return getEntityManager().findByDaoClass(this.getClass());
}
}
public static class DaoImplTwo extends IDao {
@Override
protected String getData() {
return getEntityManager().findByDaoClass(this.getClass());
}
}
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.CONSTRUCTOR})
public static @interface CustomContext{}
public static class CustomContextResolver
implements InjectionResolver<CustomContext> {
@Inject
private ServiceLocator locator;
@Inject
private IDaoProviders daoClasses;
@Inject
private CloseableService closeableService;
@Override
public Object resolve(Injectee injectee, ServiceHandle<?> root) {
Type requiredType = injectee.getRequiredType();
for (Class type: daoClasses.getDaoClasses()) {
if (requiredType == type) {
IDao dao = locator.getService(IDao.class, type.getCanonicalName());
addToCloseableService(dao);
return type.cast(dao);
}
}
return null;
}
private void addToCloseableService(final IDao idao) {
closeableService.add(new Closeable(){
@Override
public void close() throws IOException {
idao.close();
}
});
}
@Override
public boolean isConstructorParameterIndicator() {
return false;
}
@Override
public boolean isMethodParameterIndicator() {
return false;
}
}
public static class DummyEntityManagerFactory
extends AbstractContainerRequestValueFactory<DummyEntityManager> {
@Override
public DummyEntityManager provide() {
ContainerRequest request = getContainerRequest();
// get some condition for EntityManager
return new DummyEntityManager();
}
}
public static class IDaoProviders {
private final List<Class<? extends IDao>> daoClasses;
public IDaoProviders(Class<? extends IDao> ... daoClasses) {
this.daoClasses = new ArrayList<>(Arrays.asList(daoClasses));
}
public List<Class<? extends IDao>> getDaoClasses() {
return daoClasses;
}
}
public static class DaoFeature implements Feature {
private final Class<? extends IDao>[] daoClasses;
public DaoFeature(Class<? extends IDao> ... daoClasses) {
this.daoClasses = daoClasses;
}
@Override
public boolean configure(FeatureContext context) {
context.register(new Binder());
return true;
}
private class Binder extends AbstractBinder {
@Override
protected void configure() {
bind(CustomContextResolver.class)
.to(new TypeLiteral<InjectionResolver<CustomContext>>(){})
.in(Singleton.class);
bindFactory(DummyEntityManagerFactory.class)
.to(DummyEntityManager.class)
.in(RequestScoped.class);
for (Class<? extends IDao> daoClass: daoClasses) {
bind(daoClass).to(IDao.class)
.named(daoClass.getCanonicalName()).in(RequestScoped.class);
}
IDaoProviders daoProviders = new IDaoProviders(daoClasses);
bind(daoProviders).to(IDaoProviders.class);
}
}
}
@Path("dao")
public static class DaoResource {
@CustomContext
private DaoImplOne daoOne;
@CustomContext
private DaoImplTwo daoTwo;
@GET
@Path("one")
public String getOne() {
return daoOne.getData();
}
@GET
@Path("two")
public String getTwo() {
return daoTwo.getData();
}
}
@Override
public ResourceConfig configure() {
return new ResourceConfig(DaoResource.class)
.register(new DaoFeature(DaoImplOne.class, DaoImplTwo.class));
}
@Test
public void should_return_dao_one_data() {
Response response = target("dao/one").request().get();
assertEquals(200, response.getStatus());
assertEquals("Data from DaoImplOne", response.readEntity(String.class));
response.close();
}
@Test
public void should_return_dao_two_data() {
Response response = target("dao/two").request().get();
assertEquals(200, response.getStatus());
assertEquals("Data from DaoImplTwo", response.readEntity(String.class));
response.close();
}
}
使用 web.xml(无 ResourceConfig)
import java.io.Closeable;
import java.io.IOException;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.core.Response;
import org.glassfish.hk2.api.Injectee;
import org.glassfish.hk2.api.InjectionResolver;
import org.glassfish.hk2.api.ServiceHandle;
import org.glassfish.hk2.api.ServiceLocator;
import org.glassfish.hk2.api.TypeLiteral;
import org.glassfish.hk2.utilities.binding.AbstractBinder;
import org.glassfish.jersey.internal.util.PropertiesHelper;
import org.glassfish.jersey.process.internal.RequestScoped;
import org.glassfish.jersey.server.CloseableService;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.internal.inject.AbstractContainerRequestValueFactory;
import org.glassfish.jersey.servlet.ServletContainer;
import org.glassfish.jersey.test.DeploymentContext;
import org.glassfish.jersey.test.JerseyTest;
import org.glassfish.jersey.test.ServletDeploymentContext;
import org.glassfish.jersey.test.grizzly.GrizzlyWebTestContainerFactory;
import org.glassfish.jersey.test.spi.TestContainerFactory;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class WebXmlCustomDaoTest extends JerseyTest {
public static class DummyEntityManager {
String findByDaoClass(Class cls) {
return "Data from " + cls.getSimpleName();
}
public void close() { /* noop */ }
}
public static abstract class IDao {
private static final Logger LOG = Logger.getLogger(IDao.class.getName());
@Inject
private DummyEntityManager em;
protected abstract String getData();
public void close() {
LOG.log(Level.INFO, "Closing IDAO: {0}", this.getClass().getName());
em.close();
}
protected DummyEntityManager getEntityManager() {
return em;
}
}
public static class DaoImplOne extends IDao {
@Override
public String getData() {
return getEntityManager().findByDaoClass(this.getClass());
}
}
public static class DaoImplTwo extends IDao {
@Override
protected String getData() {
return getEntityManager().findByDaoClass(this.getClass());
}
}
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.CONSTRUCTOR})
public static @interface CustomContext {
}
public static class CustomContextResolver
implements InjectionResolver<CustomContext> {
@Inject
private ServiceLocator locator;
@Inject
private IDaoProviders daoClasses;
@Inject
private CloseableService closeableService;
@Override
public Object resolve(Injectee injectee, ServiceHandle<?> root) {
Type requiredType = injectee.getRequiredType();
for (Class type : daoClasses.getDaoClasses()) {
if (requiredType == type) {
IDao dao = locator.getService(IDao.class, type.getCanonicalName());
addToCloseableService(dao);
return type.cast(dao);
}
}
return null;
}
private void addToCloseableService(final IDao idao) {
closeableService.add(new Closeable() {
@Override
public void close() throws IOException {
idao.close();
}
});
}
@Override
public boolean isConstructorParameterIndicator() {
return false;
}
@Override
public boolean isMethodParameterIndicator() {
return false;
}
}
public static class DummyEntityManagerFactory
extends AbstractContainerRequestValueFactory<DummyEntityManager> {
@Override
public DummyEntityManager provide() {
ContainerRequest request = getContainerRequest();
// get some condition for EntityManager
return new DummyEntityManager();
}
}
public static class IDaoProviders {
private final List<Class<? extends IDao>> daoClasses;
public IDaoProviders(Class<? extends IDao>... daoClasses) {
this.daoClasses = new ArrayList<>(Arrays.asList(daoClasses));
}
public List<Class<? extends IDao>> getDaoClasses() {
return daoClasses;
}
}
public static class DaoFeature implements Feature {
public static final String DAO_IMPLEMENTATIONS = "dao.implementations";
@Override
public boolean configure(FeatureContext context) {
Map<String, Object> props = context.getConfiguration().getProperties();
String initParam = getValue(props, DAO_IMPLEMENTATIONS, String.class);
context.register(new Binder(getFromStringParam(initParam)));
return true;
}
private List<Class<? extends IDao>> getFromStringParam(String initParam) {
String[] daoClassNames = initParam.split(",");
List<Class<? extends IDao>> daoClasses = new ArrayList<>();
for (int i = 0; i < daoClassNames.length; i++) {
try {
String classname = daoClassNames[i].trim();
Class<?> cls = Class.forName(daoClassNames[i].trim());
if (IDao.class.isAssignableFrom(cls)) {
Class<? extends IDao> c = (Class<? extends IDao>)cls;
daoClasses.add(c);
}
} catch (ClassNotFoundException ex) {
// noop - ignore non IDao classes.
System.out.println(ex.getMessage());
}
}
return daoClasses;
}
public static <T> T getValue(Map<String, ?> properties, String key, Class<T> type) {
return PropertiesHelper.getValue(properties, key, type, null);
}
private class Binder extends AbstractBinder {
List<Class<? extends IDao>> daoClasses;
public Binder(List<Class<? extends IDao>> daoClasses) {
this.daoClasses = daoClasses;
}
@Override
protected void configure() {
bind(CustomContextResolver.class)
.to(new TypeLiteral<InjectionResolver<CustomContext>>() {
})
.in(Singleton.class);
bindFactory(DummyEntityManagerFactory.class)
.to(DummyEntityManager.class)
.in(RequestScoped.class);
for (Class<? extends IDao> daoClass : daoClasses) {
bind(daoClass).to(IDao.class)
.named(daoClass.getCanonicalName()).in(RequestScoped.class);
}
Class<? extends IDao>[] array = daoClasses.toArray(new Class[]{});
IDaoProviders daoProviders = new IDaoProviders(array);
bind(daoProviders).to(IDaoProviders.class);
}
}
}
@Path("dao")
public static class DaoResource {
@CustomContext
private DaoImplOne daoOne;
@CustomContext
private DaoImplTwo daoTwo;
@GET
@Path("one")
public String getOne() {
return daoOne.getData();
}
@GET
@Path("two")
public String getTwo() {
return daoTwo.getData();
}
}
@Override
protected TestContainerFactory getTestContainerFactory() {
return new GrizzlyWebTestContainerFactory();
}
/**
*
* This method is to configure a web deployment using a "web.xml".
*
* The "dao.implementations" is a property from the `DaoFeature`
* The user should list the `IDao` implementation classes separated
* by a comma.
*
* The `DaoFeature` is register with the Jersey init-param
* `jersey.config.server.provider.classnames`
*
* The class names I listed use a `$` only because they are inner classes.
* Normally you would not need that.
*
* See http://stackoverflow.com/a/7007859/2587435
*/
@Override
protected DeploymentContext configureDeployment() {
return ServletDeploymentContext
.forServlet(ServletContainer.class)
.initParam("jersey.config.server.provider.packages",
this.getClass().getPackage().getName())
.initParam("jersey.config.server.provider.classnames",
"com.stackoverflow.dao.WebXmlCustomDaoTest$DaoFeature")
.initParam("dao.implementations",
"com.stackoverflow.dao.WebXmlCustomDaoTest$DaoImplOne,"
+ "com.stackoverflow.dao.WebXmlCustomDaoTest$DaoImplTwo")
.build();
}
@Test
public void should_return_dao_one_data() {
Response response = target("dao/one").request().get();
assertEquals(200, response.getStatus());
assertEquals("Data from DaoImplOne", response.readEntity(String.class));
response.close();
}
@Test
public void should_return_dao_two_data() {
Response response = target("dao/two").request().get();
assertEquals(200, response.getStatus());
assertEquals("Data from DaoImplTwo", response.readEntity(String.class));
response.close();
}
}
关于java - 具有接口(interface)类型和 InjectionResolver 的 HK2 Factory，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33037092/
25
4
0
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我什至不知道这是否可能，我非常怀疑它是否可能，但如果可以，您能告诉我怎么做吗？我只是想知道如何从打印机打印一些文本。 有什么想法吗？ 最佳答案 这里有更简单的事情。 import javax.swin
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