如何从 JAVA 调用 AWS lambda 函数？

Question

I have multiple lambda functions (get, post ...) and I want to return a JSON or JSON String. How can I call "get" ("Get" lambda returns list of objects) function from JAVA code, which doesn't require any parameters/payload? Also It returns:

{StatusCode: 200,Payload: Sensitive Data Redacted ,ExecutedVersion: $LATEST}

Lambdas have required permissions:

• lambda:InvokeFunction
• lambda:InvokeAsync

Method:

public String invokeLambda(String operationName, JSONObject jsonObject) throws JSONException {
    AWSLambda lambdaClient = AWSLambdaClientBuilder.defaultClient();
    InvokeRequest request = new InvokeRequest();
    request.withInvocationType(InvocationType.RequestResponse);
    request.withFunctionName(operationName)
            .withPayload(payload);
    InvokeResult invoke = lambdaClient.invoke(request);
    return invoke.toString();
}

Answer 1

If you are working with AWS SDK 2.0 you can call a lambda function like this

    public static void invokeFunction(LambdaClient awsLambda, String functionName) {

         InvokeResponse res = null ;
        try {
            //Need a SdkBytes instance for the payload
            String json = "{\"Hello \":\"Paris\"}";
            SdkBytes payload = SdkBytes.fromUtf8String(json) ;

            //Setup an InvokeRequest
            InvokeRequest request = InvokeRequest.builder()
                    .functionName(functionName)
                    .payload(payload)
                    .build();

            res = awsLambda.invoke(request);
            String value = res.payload().asUtf8String() ;
            System.out.println(value);

        } catch(LambdaException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
    }

See here

You can then parse the json string into an object, by using a class like ObjectMapper or similar.