java - Amazon Lambda 上 Amazon Echo/Alexa 的正确 Java handleRequest() 方法签名？

Question

我正在尝试创建一个 Amazon Lambda以 Java 实现的功能，可与 Amazon Echo/Alexa 配合使用.我使用 Eclipse Mars 作为 IDE。

这是我的 LambdaFunctionHandler 的样子，它将接收来自 Alexa 的请求:

public class LambdaFunctionHandler implements RequestHandler<SpeechletRequestEnvelope, SpeechletResponse> {

    @Override
    public SpeechletResponse handleRequest(SpeechletRequestEnvelope input, Context context) {
        context.getLogger().log("Input: " + input);

        // TODO: implement your handler
        return null;
    }
}

但是，当尝试使用来自 Alexa 的示例 JSON 输入对此进行测试时，我在 Eclipse 中收到错误:

{"errorMessage":"An error occurred during JSON parsing","errorType":"java.lang.RuntimeException","stackTrace":[],"cause":{"errorMessage":"Lcom/fasterxml/jackson/databind/ObjectMapper;","errorType":"java.lang.NoClassDefFoundError","stackTrace":["java.lang.Class.getDeclaredFields0(Native Method)","java.lang.Class.privateGetDeclaredFields(Class.java:2583)","java.lang.Class.getDeclaredFields(Class.java:1916)","com.fasterxml.jackson.databind.introspect.AnnotatedClass._findFields(AnnotatedClass.java:689)","com.fasterxml.jackson.databind.introspect.AnnotatedClass.resolveFields(AnnotatedClass.java:470)","com.fasterxml.jackson.databind.introspect.AnnotatedClass.fields(AnnotatedClass.java:282)","com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector._addFields(POJOPropertiesCollector.java:390)","com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector.collect(POJOPropertiesCollector.java:243)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.collectProperties(BasicClassIntrospector.java:197)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forDeserialization(BasicClassIntrospector.java:110)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forDeserialization(BasicClassIntrospector.java:15)","com.fasterxml.jackson.databind.DeserializationConfig.introspect(DeserializationConfig.java:703)","com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:330)","com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:265)","com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:245)","com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:143)","com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:439)","com.fasterxml.jackson.databind.ObjectReader._prefetchRootDeserializer(ObjectReader.java:1588)","com.fasterxml.jackson.databind.ObjectReader.(ObjectReader.java:185)","com.fasterxml.jackson.databind.ObjectMapper._newReader(ObjectMapper.java:558)","com.fasterxml.jackson.databind.ObjectMapper.reader(ObjectMapper.java:3098)"],"cause":{"errorMessage":"com.fasterxml.jackson.databind.ObjectMapper","errorType":"java.lang.ClassNotFoundException","stackTrace":["java.net.URLClassLoader.findClass(URLClassLoader.java:381)","java.lang.ClassLoader.loadClass(ClassLoader.java:424)","java.lang.ClassLoader.loadClass(ClassLoader.java:357)","java.lang.Class.getDeclaredFields0(Native Method)","java.lang.Class.privateGetDeclaredFields(Class.java:2583)","java.lang.Class.getDeclaredFields(Class.java:1916)","com.fasterxml.jackson.databind.introspect.AnnotatedClass._findFields(AnnotatedClass.java:689)","com.fasterxml.jackson.databind.introspect.AnnotatedClass.resolveFields(AnnotatedClass.java:470)","com.fasterxml.jackson.databind.introspect.AnnotatedClass.fields(AnnotatedClass.java:282)","com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector._addFields(POJOPropertiesCollector.java:390)","com.fasterxml.jackson.databind.introspect.POJOPropertiesCollector.collect(POJOPropertiesCollector.java:243)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.collectProperties(BasicClassIntrospector.java:197)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forDeserialization(BasicClassIntrospector.java:110)","com.fasterxml.jackson.databind.introspect.BasicClassIntrospector.forDeserialization(BasicClassIntrospector.java:15)","com.fasterxml.jackson.databind.DeserializationConfig.introspect(DeserializationConfig.java:703)","com.fasterxml.jackson.databind.deser.DeserializerCache._createDeserializer(DeserializerCache.java:330)","com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:265)","com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:245)","com.fasterxml.jackson.databind.deser.DeserializerCache.findValueDeserializer(DeserializerCache.java:143)","com.fasterxml.jackson.databind.DeserializationContext.findRootValueDeserializer(DeserializationContext.java:439)","com.fasterxml.jackson.databind.ObjectReader._prefetchRootDeserializer(ObjectReader.java:1588)","com.fasterxml.jackson.databind.ObjectReader.(ObjectReader.java:185)","com.fasterxml.jackson.databind.ObjectMapper._newReader(ObjectMapper.java:558)","com.fasterxml.jackson.databind.ObjectMapper.reader(ObjectMapper.java:3098)"]}}}

这是我的 JSON 输入(取自 TestColors example 在线):

{
  "session": {
    "new": false,
    "sessionId": "session1234",
    "attributes": {},
    "user": {
      "userId": null
    },
    "application": {
      "applicationId": "amzn1.echo-sdk-ams.app.[unique-value-here]"
    }
  },
  "version": "1.0",
  "request": {
    "intent": {
      "slots": {
        "Color": {
          "name": "Color",
          "value": "red"
        }
      },
      "name": "MyColorIsIntent"
    },
    "type": "IntentRequest",
    "requestId": "request5678"
  }
}

因此，显然 Amazon SpeechletRequestEnvelope 不是 handleRequest() 的正确输入类。

handleRequest() 从 Alexa 接收请求的正确方法签名是什么？

我找不到与 Alexa/Echo 配合使用的 Amazon Lambda Java 示例。

Answer 1

这是一个完整的工作示例:

public class LambdaFunctionHandler implements RequestStreamHandler {

    @Override
    public void handleRequest(InputStream inputStream, OutputStream output, Context context) throws IOException {
        byte serializedSpeechletRequest[] = IOUtils.toByteArray(inputStream);
        SpeechletRequestEnvelope requestEnvelope = SpeechletRequestEnvelope.fromJson(serializedSpeechletRequest);
        SpeechletRequest speechletRequest = requestEnvelope.getRequest();

        if (speechletRequest instanceof IntentRequest) {
            IntentRequest ir = (IntentRequest) speechletRequest;
            String outString = "IntentRequest name: " + ir.getIntent().getName();
            context.getLogger().log(outString);
            output.write(outString.getBytes());
        }
    }
}

请注意，此类实现的是 RequestStreamHandler，而不是 RequestHandler。

使用问题中的输入 JSON，output.write(outString.getBytes()) 将输出到 Eclipse AWS Lambda 控制台:

==================== FUNCTION OUTPUT ====================

IntentRequest name: MyColorIsIntent

...while context.getLogger().log(outString); 导致同一行在线写入 Amazon Lambda 控制台。

您还需要确保您的项目中有一个文件夹/lib，并且需要包含以下JAR:

• commons-codec-1.6.jar
• commons-lang3-3.x.jar
• jackson-annotations-2.3.2.jar
• jackson-core-2.3.2.jar
• jackson-databind-2.3.2.jar
• JakartaCommons-IO-2.4.jar
• joda-time-2.3.jar
• log4j.1.2.17.jar
• servlet-api-3.0.jar
• slf4j-api-1.7.4.jar
• slf4j-log4j12-1.7.4.jar
• alexa-skills-kit-1.0.jar

这些 JAR 可以从 Maven Central 下载，或来自 AlexaSkillsKit.zip 中的“第三方”子文件夹.

在 Eclipse 中，您需要刷新项目以便它在 /lib 目录中看到 JAR 文件(只需按 F5)，然后将 JAR 添加到 Java 构建路径:

1. 在 Eclipse 中右键单击 Lambda 项目的根目录
2. 点击“属性”
3. 选择“Java 构建路径”
4. 选择“库”标签
5. 点击“添加 JAR”
6. 浏览到“库”
7. 选择“lib”文件夹中的所有 JAR，然后单击“确定”，直到您返回到 Eclipse 主屏幕

感谢@jephers 提供了指向 Github 上这个很棒的教程的指针，我从中拼凑了很多内容:

https://github.com/jjaquinta/EchoProofOfConcepts/tree/master/jo.echo.lambda