注入Jersey资源类 [英] Injecting into a Jersey Resource class
问题描述
我确实尝试了以下链接
如何将协作者连接到泽西岛资源？
和
访问Jersey资源类中的外部对象
但是我仍然无法找到一个显示如何注入Resource类的工作示例。
我没有使用Spring或网络容器。
I did try going through the following links How to wire in a collaborator into a Jersey resource? and Access external objects in Jersey Resource class But still i am unable to find a working sample which shows how to inject into a Resource class. I am not using Spring or a web container.
我的资源是
package resource;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
@Path("/something")
public class Resource
{
@MyResource
Integer foo = null;
private static String response = "SampleData from Resource";
public Resource()
{
System.out.println("...constructor called :" + foo);
}
@Path("/that")
@GET
@Produces("text/plain")
public String sendResponse()
{
return response + "\n";
}
}
我的提供商
package resource;
import javax.ws.rs.ext.Provider;
import com.sun.jersey.core.spi.component.ComponentContext;
import com.sun.jersey.core.spi.component.ComponentScope;
import com.sun.jersey.spi.inject.Injectable;
import com.sun.jersey.spi.inject.InjectableProvider;
@Provider
public class MyResourceProvider implements InjectableProvider<MyResource, Integer>
{
@Override
public ComponentScope getScope()
{
return ComponentScope.PerRequest;
}
@Override
public Injectable getInjectable(final ComponentContext arg0, final MyResource arg1, final Integer arg2)
{
return new Injectable<Object>()
{
@Override
public Object getValue()
{
return new Integer(99);
}
};
}
}
我的EndpointPublisher
import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.core.MediaType;
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.container.grizzly.GrizzlyWebContainerFactory;
class EndpointPublisher
{
public static void main(final String[] args)
{
final String address = "http://localhost:8080/";
final Map<String, String> config = new HashMap<String, String>();
config.put("com.sun.jersey.config.property.packages", "resource");
try
{
GrizzlyWebContainerFactory.create(address, config);
System.out.println("server started ....." + address);
callGet();
}
catch (final Exception e)
{
e.printStackTrace();
}
}
public static void callGet()
{
Client client = null;
ClientResponse response = null;
client = Client.create();
final WebResource resource =
client.resource("http://localhost:8080/something");
response = resource.path("that")
.accept(MediaType.TEXT_XML_TYPE, MediaType.APPLICATION_XML_TYPE)
.type(MediaType.TEXT_XML)
.get(ClientResponse.class);
System.out.println(">>>> " + response.getResponseDate());
}
}
我的注释
@Retention(RetentionPolicy.RUNTIME)
public @interface MyResource
{}
但是当我执行我的EndpointPublisher时，我无法注入foo !!
But when i execute my EndpointPublisher i am unable to inject foo!!
推荐答案
您的InjectableProvider未正确实现。第二个类型参数不应该是您尝试注入的字段的类型 - 而应该是上下文 - java.lang.reflect.Type类或com.sun.jersey.api.model.Parameter类。在您的情况下，您将使用类型。因此，您的InjectableProvider实现应如下所示：
Your InjectableProvider is not implemented correctly. The second type parameter should not be the type of the field you are trying to inject - instead it should be the context - either java.lang.reflect.Type class or com.sun.jersey.api.model.Parameter class. In your case, you would use Type. So, your InjectableProvider implementation should look as follows:
package resource;
import javax.ws.rs.ext.Provider;
import com.sun.jersey.core.spi.component.ComponentContext;
import com.sun.jersey.core.spi.component.ComponentScope;
import com.sun.jersey.spi.inject.Injectable;
import com.sun.jersey.spi.inject.InjectableProvider;
import java.lang.reflect.Type;
@Provider
public class MyResourceProvider implements InjectableProvider<MyResource, Type> {
@Override
public ComponentScope getScope() {
return ComponentScope.PerRequest;
}
@Override
public Injectable getInjectable(final ComponentContext arg0, final MyResource arg1, final Type arg2) {
if (Integer.class.equals(arg2)) {
return new Injectable<Integer>() {
@Override
public Integer getValue() {
return new Integer(99);
}
};
} else {
return null;
}
}
}
有一个帮助类每请求可注射提供程序（PerRequestTypeInjectableProvider）以及单例可注入提供程序（SingletonTypeInjectableProvider），因此您可以通过继承它来进一步简化它：
There is a helper class for per-request injectable providers (PerRequestTypeInjectableProvider) as well as singleton injectable providers (SingletonTypeInjectableProvider), so you can further simplify it by inheriting from that:
package resource;
import javax.ws.rs.ext.Provider;
import com.sun.jersey.core.spi.component.ComponentContext;
import com.sun.jersey.spi.inject.Injectable;
import com.sun.jersey.spi.inject.PerRequestTypeInjectableProvider;
@Provider
public class MyResourceProvider extends PerRequestTypeInjectableProvider<MyResource, Integer> {
public MyResourceProvider() {
super(Integer.class);
}
@Override
public Injectable<Integer> getInjectable(ComponentContext ic, MyResource a) {
return new Injectable<Integer>() {
@Override
public Integer getValue() {
return new Integer(99);
}
};
}
}
请注意，对于这些辅助类，第二个类型参数是字段的类型。
Note that for these helper classes the second type parameter is the type of the field.
还有一件事 - 在调用构造函数之后注入，因此资源的构造函数仍然是打印出 ...构造函数调用：null ，但是如果你改变你的资源方法以返回foo，你会看到你得到的响应将是99。
And one more thing - the injection happens after the constructor is called, so the constructor of your resource will still print out ...constructor called :null, but if you change your resource method to return foo, you'll see the response you'll get will be 99.
这篇关于注入Jersey资源类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
