Jersey 2 筛选器在客户端请求筛选器中使用容器请求上下文

我发现了一个很好的方法来做到这一点，它不用于在 和 之间进行通信，因为你不能假设响应容器请求的客户端请求将在同一线程上。ThreadLocalContainerRequestFilterClientRequestFilter

我实现此目的的方法是在 .然后，我可以将对象（显式或通过依赖注入）传递到我的.如果您使用依赖注入（如果您使用的是 Jersey 2，那么您可能使用的是 HK2），那么所有这些都可以在不修改任何资源级别逻辑的情况下实现。ContainerRequestConextContainerRequestFilterContainerRequestContextClientRequestFilter

有一个这样的：ContainerRequestFilter

public class RequestIdContainerFilter implements ContainerRequestFilter {

@Override
public void filter(ContainerRequestContext containerRequestContext) throws IOException {
    containerRequestContext.setProperty("property-name", "any-object-you-like");
}

和 一个在其构造函数中采用一个：ClientRequestFilterContainerRequestContext

public class RequestIdClientRequestFilter implements ClientRequestFilter {

    private ContainerRequestContext containerRequestContext;

    public RequestIdClientRequestFilter(ContainerRequestContext containerRequestContext) {
        this.containerRequestContext = containerRequestContext;
    }

    @Override
    public void filter(ClientRequestContext clientRequestContext) throws IOException {
        String value = containerRequestContext.getProperty("property-name");
        clientRequestContext.getHeaders().putSingle("MyHeader", value);
    }
}

然后，这只是一个将这一切联系在一起的情况。您将需要一个工厂来创建任何或您需要的：ClientWebTarget

public class MyWebTargetFactory implements Factory<WebTarget> {

    @Context
    private ContainerRequestContext containerRequestContext;

    @Inject
    public MyWebTargetFactory(ContainerRequestContext containerRequestContext) {
        this.containerRequestContext = containerRequestContext;
    }

    @Override
    public WebTarget provide() {
        Client client = ClientBuilder.newClient();
        client.register(new RequestIdClientRequestFilter(containerRequestContext));
        return client.target("path/to/api");
    }

    @Override
    public void dispose(WebTarget target) {

    }
}

然后注册过滤器并将工厂绑定到您的主应用程序上：ResourceConfig

public class MyApplication extends ResourceConfig {

    public MyApplication() {
        register(RequestIdContainerFilter.class);
        register(new AbstractBinder() {
            @Override
            protected void configure() {
                bindFactory(MyWebTargetFactory.class).to(WebTarget.class);
            }
        }
    }
}

容器筛选器可以在一个类中实现这两种功能。客户端筛选器也是如此，两者都可以在单个筛选器实现中实现。ContainerRequestFilterContainerResponseFilterClientRequestFilterClientResponseFilter

但据我所知，你不能混在一起。相反，您可以有两个单独的过滤器相互通信，例如使用模式：ThreadLocal

// Container filter that stores the request context in a ThreadLocal variable
public class MyContainerRequestFilter implements ContainerRequestFilter, ContainerResponseFilter {
    public static final ThreadLocal<ContainerRequestContext> requestContextHolder;

    @Override
    public void filter(ContainerRequestContext requestContext) throws IOException {
        requestContextHolder.set(requestContext);
    }

    @Override
    public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext) throws IOException {
        // clean up after request
        requestContextHolder.remove();
    }
}

// Client request filter that uses the info from MyContainerRequestFilter
public class MyClientRequestFilter implements ClientRequestFilter {
    @Override
    public void filter(ClientRequestContext requestContext) throws IOException {
        ContainerRequestContext containerRequestContext =
            MyContainerRequestFilter.requestContextHolder.get();
        if (containerRequestContext != null) {
            // TODO: use info from containerRequestContext to modify client request
        }
    }
}