同一URL下不同HTTP动词配置独立Grizzly HttpHandler的实现问题

核心原因 #

Grizzly HTTP Server的路由规则为：同路径下绑定的多个HttpHandler仅会按注册顺序调用第一个匹配到路径的Handler，不会自动降级触发后续注册的Handler，这是你当前POST请求也会触发GetHandler返回错误内容的根本原因。

方案选择 #

你提到的两种实现思路都可行，可根据场景选择：

• 轻量场景推荐单Handler内部判断方法：代码更简洁，无额外路由开销，适合单路径下处理方法不多的场景
• 若不同方法的处理逻辑复杂，想要拆分独立类维护，可以自行实现一个调度Handler，统一路由到对应子Handler

修正代码示例 #

方案1：单Handler内部判断方法 #

import java.net.URI;

import javax.ws.rs.client.ClientBuilder;

import org.glassfish.grizzly.http.Method;
import org.glassfish.grizzly.http.server.HttpHandler;
import org.glassfish.grizzly.http.server.HttpServer;
import org.glassfish.grizzly.http.server.Request;
import org.glassfish.grizzly.http.server.Response;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpServerFactory;

public class HttpHandlerTest
{
    private static final URI BASE_URI = URI.create("http://localhost:8081");
    private static final String MAPPING = "/test";

    public static void main(String[] args)
    {
        HttpServer server = GrizzlyHttpServerFactory.createHttpServer(BASE_URI, (GrizzlyHttpContainer) null, false, null, true);
        // 仅注册一个统一处理Handler
        server.getServerConfiguration().addHttpHandler(new UnifiedHandler(), MAPPING);
        
        javax.ws.rs.core.Response getResponse = ClientBuilder.newClient().target(BASE_URI + MAPPING).request().get();
        System.out.println(getResponse.readEntity(String.class)); // 输出 GET response
        javax.ws.rs.core.Response postResponse = ClientBuilder.newClient().target(BASE_URI + MAPPING).request().post(null);
        System.out.println(postResponse.readEntity(String.class)); // 输出 POST response
        server.shutdown();
    }

    public static class UnifiedHandler extends HttpHandler{
        @Override
        public void service(Request request, Response response) throws Exception{
            if (request.getMethod() == Method.GET){
                response.getWriter().write("GET response");
            } else if (request.getMethod() == Method.POST) {
                response.getWriter().write("POST response");
            } else {
                response.setStatus(405);
                response.getWriter().write("Method Not Allowed");
            }
        }
    }
}

方案2：多Handler拆分+调度转发 #

如果需要将不同方法的处理逻辑拆分为独立类，加一层调度Handler即可：

import java.net.URI;

import javax.ws.rs.client.ClientBuilder;

import org.glassfish.grizzly.http.Method;
import org.glassfish.grizzly.http.server.HttpHandler;
import org.glassfish.grizzly.http.server.HttpServer;
import org.glassfish.grizzly.http.server.Request;
import org.glassfish.grizzly.http.server.Response;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer;
import org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpServerFactory;

public class HttpHandlerTest
{
    private static final URI BASE_URI = URI.create("http://localhost:8081");
    private static final String MAPPING = "/test";

    public static void main(String[] args)
    {
        HttpServer server = GrizzlyHttpServerFactory.createHttpServer(BASE_URI, (GrizzlyHttpContainer) null, false, null, true);
        // 仅注册调度Handler
        server.getServerConfiguration().addHttpHandler(new DispatchHandler(), MAPPING);
        
        javax.ws.rs.core.Response getResponse = ClientBuilder.newClient().target(BASE_URI + MAPPING).request().get();
        System.out.println(getResponse.readEntity(String.class));
        javax.ws.rs.core.Response postResponse = ClientBuilder.newClient().target(BASE_URI + MAPPING).request().post(null);
        System.out.println(postResponse.readEntity(String.class));
        server.shutdown();
    }

    // 统一调度Handler
    public static class DispatchHandler extends HttpHandler{
        private final GetHandler getHandler = new GetHandler();
        private final PostHandler postHandler = new PostHandler();

        @Override
        public void service(Request request, Response response) throws Exception{
            if (request.getMethod() == Method.GET){
                getHandler.service(request, response);
            } else if (request.getMethod() == Method.POST) {
                postHandler.service(request, response);
            } else {
                response.setStatus(405);
                response.getWriter().write("Method Not Allowed");
            }
        }
    }

    public static class GetHandler extends HttpHandler{
        @Override
        public void service(Request request, Response response) throws Exception{
            response.getWriter().write("GET response");
        }
    }

    public static class PostHandler extends HttpHandler{
        @Override
        public void service(Request request, Response response) throws Exception{
            response.getWriter().write("POST response");
        }
    }
}

补充说明 #

不需要引入额外的上层组件，上述两种方案都可基于Grizzly原生能力实现，你之前的思路问题在于对Grizzly的路由匹配规则不熟悉，误以为同路径下多个Handler会依次触发，实际框架没有内置该逻辑，需要自行实现调度。

内容的提问来源于stack exchange，提问作者Amber