如何解析Spring集成HTTP網關響應到Bean中？

Question

我一直在嘗試爲實踐目的獲得一個簡單的集成工作流程。事情是我剛剛開始與Spring合作，而且我很難理解集成及其工作原理。

現在我已經得到了與Spring MVC的一個非常簡單的後端應用程序，返回

[ 
{"id":1,"name":"Series test","synopsis":"Testing reading items from JSON.","imageUrl":"http://some.where/images/some_image.png"}, 
{"id":2,"name":"Arrow","synopsis":"Some guy in a hood shooting arrows to some guys with superpowers.","imageUrl":"http://some.where/images/some_image.png"}, 
{"id":3,"name":"Primeval","synopsis":"Some guys with guns killing dinosaurs and lots of infidelity.","imageUrl":"http://some.where/images/some_image.png"}, 
{"id":4,"name":"Dr. Who","synopsis":"It's bigger on the inside.","imageUrl":"http://some.where/images/some_image.png"}, 
{"id":5,"name":"Fringe","synopsis":"Weird things happen.","imageUrl":"http://some.where/images/some_image.png"}, 
{"id":6,"name":"Monster Hunter Freedom Unite","synopsis":"Wait. This is a game.","imageUrl":"http://some.where/images/some_image.png"} 
] 

到http://localhost:9000/api/series/findAll和一個可運行的Spring項目，與整合，嘗試恢復數據，並將其轉換爲Series （具有與JSON相同屬性的bean）數組。

如果我沒有添加reply-channel到outbound-gateway一切正常。但是，當我將它發送到另一個頻道以解析它到一個Series對象時，我開始在新頻道上看到「調度程序沒有訂閱者」。這是有道理的，但它讓我不知道如何着手。

我的項目文件，除了系列，像現在這樣的權利：

Startup.java

package com.txus.integration; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 

import java.util.List; 
import java.util.concurrent.Future; 

public class Startup { 
    @Autowired 
    RequestGateway requestGateway; 

    public static void main(String[] args) throws Exception { 
     ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/META-INF/spring/integration-components.xml"); 

     RequestGateway requestGateway = context.getBean(RequestGateway.class); 
     Future<String> promise = requestGateway.getSeries(""); 

     while (!promise.isDone()) { 
      Thread.sleep(1000); 
     } 
     String response = promise.get(); 
     printReadable(response); 

     context.close(); 
     System.exit(0); 
    } 

    public static void printReadable(String string) { 
     String separator = "= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ="; 
     System.out.println("\n" + separator + "\n" + string + "\n" + separator + "\n"); 
    } 

    public static void printReadable(List<String> strings) { 
     for (String string : strings) printReadable(string); 
    } 
} 

---

RequestGateway

package com.txus.integration; 


import com.txus.entities.Series; 
import org.springframework.integration.annotation.Gateway; 

import java.util.concurrent.Future; 

public interface RequestGateway { 
    @Gateway(requestChannel="responseChannel") 
    Future<String> getSeries(String jsonString); 

    @Gateway(requestChannel="responseChannel") 
    Future<String> getSeries(Series series); 
} 

---

集成-的components.xml

<beans:beans 
     xmlns="http://www.springframework.org/schema/integration" 
     xmlns:beans="http://www.springframework.org/schema/beans" 
     xmlns:context="http://www.springframework.org/schema/context" 
     xmlns:http="http://www.springframework.org/schema/integration/http" 
     xmlns:task="http://www.springframework.org/schema/task" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
     xsi:schemaLocation=" 
    http://www.springframework.org/schema/beans     http://www.springframework.org/schema/beans/spring-beans.xsd 
    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context-3.1.xsd 
    http://www.springframework.org/schema/integration   http://www.springframework.org/schema/integration/spring-integration.xsd 
    http://www.springframework.org/schema/integration/http  http://www.springframework.org/schema/integration/http/spring-integration-http.xsd 
    http://www.springframework.org/schema/task     http://www.springframework.org/schema/task/spring-task.xsd"> 

    <context:annotation-config/> 
    <context:component-scan base-package="com.txus"/> 


    <!-- START: Spring Integration --> 
    <!-- Integration: Channels --> 

    <channel id="requestChannel"/> 
    <channel id="responseChannel"/> 

    <channel id="failedChannel"/> 


    <!-- Integration: Loggers --> 

    <logging-channel-adapter 
      id="payloadLogger" level="DEBUG" expression="'### Message [' + headers.id + '] payload: ' + payload"/> 
    <logging-channel-adapter 
      id="headersLogger" level="DEBUG" expression="'### Message [' + headers.id + '] headers: ' + headers"/> 


    <!-- Integration: Flow --> 

    <gateway 
      service-interface="com.txus.integration.RequestGateway" 
      default-request-timeout="5000" async-executor="executor"> 

     <method name="getSeries" request-channel="inputChannel"/> 
    </gateway> 

    <task:executor id="executor" pool-size="100"/> 


    <payload-type-router input-channel="inputChannel" default-output-channel="failedChannel"> 
     <mapping type="java.lang.String" channel="requestChannel"/> 
     <mapping type="com.txus.entities.Series" channel="objectToJSONChannel"/> 
    </payload-type-router> 


    <object-to-json-transformer 
      id="objectToJsonTransformer" input-channel="objectToJSONChannel" output-channel="requestChannel"/> 


    <http:outbound-gateway 
      http-method="GET" 
      expected-response-type="java.lang.String" 
      url="http://localhost:9000/api/series/findAll" 
      request-channel="requestChannel" 
      reply-channel="jsonToSeries" 
      reply-timeout="30000"/> 


    <map-to-object-transformer 
      input-channel="jsonToSeries" output-channel="responseChannel" type="com.txus.entities.Series"/> 


    <!-- END: Spring Integration --> 

</beans:beans> 

Answer 1

其中配置output-channel="responseChannel"你有最後一個組件的問題。沒有任何訂閱該頻道的內容。

我在此問題上看到您的@Gateway配置，但它有點不對。 XML配置優先於那裏的註釋。因此requestChannel到底是inputChannel。

如果您想從RequestGateway調用結果發送的<map-to-object-transformer>到responseChannel並接受它作爲一個return，你應該指定網關上配置responseChannel爲reply-channel。

從另一邊你就不需要它，TemporaryReplyChannel來救援。

請參閱Spring Integration Manual的更多信息。