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我試圖創建一個簡單的服務,其中的HTTP請求時,我得到地圖查詢參數的鍵/值對例外,我回復了一些迴應。這裏是我的配置文件的相關部分:騾3.1 - 消息變換爲http請求到參數映射變壓器
<servlet:http-request-to-parameter-map name="http-request-to-param-map"/>
<pattern:simple-service name="ScenarioIndex"
address="http://localhost:63081/index"
transformer-refs="http-request-to-param-map"
>
<component>
<singleton-object class="com.test.ScenarioIndex"/>
</component>
</pattern:simple-service>
這裏是ScenarioIndex類的相關部分。
public Object scenarioIndex(Map queryParameters) {
return queryParameters.toString();
}
首先,我只是想測試的查詢參數件工作,我覺得是這樣開始的,所以我要回的查詢參數的字符串表示。在此之後的真正實施將更加複雜。
服務器啓動正常,但當該localhost:63081/index
URL被擊中,帶或不帶查詢參數,我得到以下異常:
ERROR 2011-06-03 13:29:04,353 [connector.http.mule.default.receiver.2] org.mule.exception.DefaultServiceExceptionStrategy:
********************************************************************************
Message : The object transformed is of type: "SimpleDataType{type=org.mule.transport.NullPayload, mimeType='*/*'}", but the expected return type is "SimpleDataType{type=java.util.Map, mimeType='*/*'}". Message payload is of type: String
Type : org.mule.api.transformer.TransformerMessagingException
Code : MULE_ERROR--2
Payload : /index?param=true
JavaDoc : http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/transformer/TransformerMessagingException.html
********************************************************************************
Exception stack is:
1. The object transformed is of type: "SimpleDataType{type=org.mule.transport.NullPayload, mimeType='*/*'}", but the expected return type is "SimpleDataType{type=java.util.Map, mimeType='*/*'}". Message payload is of type: String (org.mule.api.transformer.TransformerMessagingException)
org.mule.transformer.AbstractMessageTransformer:183 (http://www.mulesoft.org/docs/site/current3/apidocs/org/mule/api/transformer/TransformerMessagingException.html)
********************************************************************************
Root Exception stack trace:
org.mule.api.transformer.TransformerMessagingException: The object transformed is of type: "SimpleDataType{type=org.mule.transport.NullPayload, mimeType='*/*'}", but the expected return type is "SimpleDataType{type=java.util.Map, mimeType='*/*'}". Message payload is of type: String
at org.mule.transformer.AbstractMessageTransformer.checkReturnClass(AbstractMessageTransformer.java:183)
at org.mule.transformer.AbstractMessageTransformer.transform(AbstractMessageTransformer.java:162)
at org.mule.transformer.AbstractMessageTransformer.transform(AbstractMessageTransformer.java:93)
at org.mule.DefaultMuleMessage.applyAllTransformers(DefaultMuleMessage.java:1305)
at org.mule.DefaultMuleMessage.applyTransformers(DefaultMuleMessage.java:1265)
at org.mule.DefaultMuleMessage.applyTransformers(DefaultMuleMessage.java:1258)
at org.mule.transformer.AbstractTransformer.process(AbstractTransformer.java:118)
at org.mule.processor.ExceptionHandlingMessageProcessor.process(ExceptionHandlingMessageProcessor.java:25)
at org.mule.transport.AbstractMessageReceiver.routeMessage(AbstractMessageReceiver.java:185)
at org.mule.transport.AbstractMessageReceiver.routeMessage(AbstractMessageReceiver.java:158)
at org.mule.transport.AbstractMessageReceiver.routeMessage(AbstractMessageReceiver.java:145)
at org.mule.transport.http.HttpMessageReceiver$HttpWorker.doRequest(HttpMessageReceiver.java:247)
at org.mule.transport.http.HttpMessageReceiver$HttpWorker.processRequest(HttpMessageReceiver.java:206)
at org.mule.transport.http.HttpMessageReceiver$HttpWorker.run(HttpMessageReceiver.java:164)
at org.mule.work.WorkerContext.run(WorkerContext.java:309)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1061)
at edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:575)
at java.lang.Thread.run(Thread.java:680)
如果我拿出參考http請求到-param-map變換器,我可以接受一個字符串並返回一個字符串。我不明白爲什麼在Map中突然停止返回String。在這方面有什麼幫助?