java - 用 guice 覆盖 Jersey 资源

Question

我正在寻找一种方法来覆盖在 GuiceServletContextListener 中与 guice 绑定(bind)的 Jersey 资源。我正在尝试运行的代码:

//Define Jersey resource interface
@Path("/books/{key}")
public interface BookDocument {

    public BookDAO getDao();

    public void setDao(BookDAO dao);
}

//Define default implementation
public class BookImpl implements Book {

    @Override
    public BookDAO getDao() {
        return dao;
    }

    @Inject
    @Override
    public void setDao(BookDAO dao) {
        this.dao = dao;
    }
}

//User wants to inject his implementation, so he define it
public class BookUserImpl implements Book {

    @Override
    public BookDAO getDao() {
        return dao;
    }

    @Inject
    @Override
    public void setDao(BookDAO dao) {
        this.dao = dao;
    }
}

//Inject default implementation of resource
public class ApplicationResourcesModule extends AbstractModule
{
    @Override
    protected void configure()
    {
        bind(Book).to(BookImpl);
    }
}

//But user wants to inject his implementation, so he bind it in users AbstractModule
public class ApplicationResourcesModuleUser extends AbstractModule
{
    @Override
    protected void configure()
    {
        bind(Book).to(BookUserImpl);
    }
}

//Bind all resources
public class JerseyGuiceConfig extends GuiceServletContextListener
{
    @Override
    protected Injector getInjector()
    {
        //Override default binding by user bindings.
        return Guice.createInjector(Modules.override(new ApplicationResourcesModule()).with(new ApplicationResourcesModuleUser()), new JerseyServletModule());
    }
}

但不幸的是，这行不通，虽然我不能像实现接口(interface)那样在 guice 中绑定(bind) Jersey 资源，只有 bind(BookImpl.class) 可以工作。但是这样的绑定(bind)是不可能被覆盖的。如果我尝试使用 bind(BookUserImpl.class) 覆盖 bind(BookImpl.class)，我会收到错误消息 Conflicting URI templates。根资源类的 URI 模板/books/{key}。 而 @Path 应该是唯一的。那么我的用例有什么解决方案吗？

Answer 1

我只是想警告您 Modules.override 对 Guice.createInjector(Stage.PRODUCTION,...) 不起作用，因此您应该仅在开发时谨慎使用它。您应该创建两个上下文监听器并以某种方式(可以说是通过 maven 配置文件)设置 web.xml 并正确实现。

更好用:

//Inject default implementation of resource
public class MainModule extends AbstractModule
{
    @Override
    protected void configure()
    {
        if(currentStage().equals(Stage.PRODUCTION) {
          install(new ApplicationResourcesModuleUser());
        } else {
          install(new ApplicationResourcesModule());
        }
    }
}

//Bind all resources
public class JerseyGuiceConfigPROD extends GuiceServletContextListener
{
    @Override
    protected Injector getInjector()
    {
        //Override default binding by user bindings.
        return Guice.createInjector(Stage.PRODUCTION, new MainModule(), new JerseyServletModule());
    }
}

public class JerseyGuiceConfigDEV extends GuiceServletContextListener
{
    @Override
    protected Injector getInjector()
    {
        //Override default binding by user bindings.
        return Guice.createInjector(Stage.DEVELOPMENT, new MainModule(), new JerseyServletModule());
    }
}

您可以在您的界面上使用@ImplementedBy 注释来说明默认实现应该是什么。因此，您不必显式绑定(bind)它，如果您绑定(bind)它，它将覆盖注释绑定(bind)。

@Path("/books/{key}")
@ImplementedBy(BookImpl.class)
public interface Book {

    public BookDAO getDao();

    @Inject //it is enough to put the injection here, i think
    public void setDao(BookDAO dao);
}

我认为这个问题与 Book 和 Book 实现绑定(bind)无关，而是与将 servlet 绑定(bind)/注册到 Jersey 容器有关。你能粘贴整个堆栈跟踪吗，guice 堆栈跟踪很冗长但很有帮助。