如何将 Grizzly 请求注入 Jersey ContainerRequestFilter

2022-01-21 00:00:00 java jersey grizzly jersey-2.0

我有灰熊提供的球衣.

我有一个 ContainerRequestFilter 实现类.但是，此类为所有传入请求创建一次.因此这样做:

I have a ContainerRequestFilter implementation class. However this class is created once for all incoming requests. Therefore doing this:

public class EndpointRequestFilter implements ContainerRequestFilter {
    @Context
    private org.glassfish.grizzly.http.server.Request requestContext;

    public void filter( ContainerRequestContext req ) throws IOException {
       // remove for sake of example
    }
}

requestContext 为空.我可以将上下文注入到被调用的实际端点中，但这相当粗糙和丑陋，对我来说真的没有用；因为我希望记录各种请求.理想情况下，希望在请求的 ResponseFilter 端获取此 Request 对象.

The requestContext is null. I can inject the context into the actual endpoint being called, but that is rather crude and ugly and really no use to me; as i wish to log various requests. Ideally would like to get at this Request object at the ResponseFilter side of the request.

必须有一个简单的方法来做到这一点.到目前为止，我看到的所有问题/答案都不适用于 Grizzly 或注入 REST 端点调用的方法.我不希望仅仅因为我想获取 IP 地址而绕过我在调用中添加这个的所有数百种方法！

There has to be an easy way of doing this. All the questions/answers I have seen thus far doesn't work for Grizzly or injects at the method being called by the REST endpoint. I don't wish to go around all my hundreds of methods adding this in call just because I want to get the IP address!

那么这里的关键是什么?我错过了什么?

So what is the key here? What am I missing?

推荐答案

我很惊讶你甚至让应用程序运行，直到你可以发现请求为空的地步.每当我尝试运行它时，我都会在启动时遇到异常，说没有请求范围，因此无法注入请求，这是我所期望的.虽然我无法重现 NPE，但我认为这个解决方案仍然可以解决您的问题.

I'm surprised you even got the app running, to get to the point where you could find out that request is null. Whenever I tried to run it, I would get an exception on start up, saying that there is no request scope, so the request can't be injected, which is what I expected. Though I couldn't reproduce the NPE, I'm thinking this solution will still solve your problem.

所以 Request 是一个请求范围的对象，因为它会随着每个请求而改变.但是过滤器本质上是一个单例.所以你需要做的是懒惰地检索它.为此，我们可以使用 javax.inject.Provider，作为一种惰性检索机制.

So the Request is a request scoped object, as it changes on every request. But the filter is by its nature, a singleton. So what you need to do, is lazily retrieve it. For that, we can use javax.inject.Provider, as a lazy retrieval mechanism.

回到我第一段的重点，这是我在启动时遇到的异常

Going back to the point in my first paragraph, this was the exception I got on start up

java.lang.IllegalStateException:不在请求范围内.

java.lang.IllegalStateException: Not inside a request scope.

这是有道理的，因为 Request 需要与请求范围相关联，而在启动时，没有.请求范围仅在请求期间存在.

This makes sense, as the Request need to be associated with a request scope, and on start up, there is none. A request scope is only present during a request.

所以使用 Provider 的作用是让我们在存在请求范围时尝试获取 Request.

So what using the Provider does, is allow us to try and grab the Request when there is a request scope present.

public static class Filter implements ContainerRequestFilter {

    @Context
    private javax.inject.Provider<Request> requestProvider;

    @Override
    public void filter(ContainerRequestContext requestContext) throws IOException {
        final Request request = requestProvider.get();
        System.out.println(request.getRemoteAddr());
    } 
}

我已经对此进行了测试，它按预期工作.

I've tested this and it works as expected.

另请参阅:

  • 使用 HK2 将请求范围对象注入单例范围对象和泽西岛

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