I have a class that scans a column from a dynamo db table, whilst using the aws sdk for java(main method taken out for simplicity):

public class fetchCmdbColumn {
    
    public static List<String> CMDB(String tableName, String tableColumn) throws Exception {

        DynamoDbClient client = DynamoDbClient.builder()
                .region(Region.EU_WEST_1)
                .build();
        List<String> ListValues = new ArrayList<>();
        
        try {
            
            ScanRequest scanRequest = ScanRequest.builder()
                        .tableName(tableName)
                        .build();
            ScanResponse response = client.scan(scanRequest);

            for (Map<String, AttributeValue> item : response.items()){
                Set<String> keys = item.keySet();
                for (String key : keys) {
                    
                    if (key == tableColumn) {
                        ListValues.add(item.get(key).s()) ;
                    }
                }
            }
            //To check what is being returned, comment out below
           // System.out.println(ListValues);
            
        } catch (DynamoDbException e){
            e.printStackTrace();
            System.exit(1);
        }
        client.close();
        return ListValues;
        
    }
}

I also have a junit tests created for that class:

public class fetchCMDBTest {


    // Define the data members required for the test
    private static String tableName = "";
    private static String tableColumn = "";


    @BeforeAll
    public static void setUp() throws IOException {

        // Run tests on Real AWS Resources
        try (InputStream input = fetchCMDBTest.class.getClassLoader().getResourceAsStream("config.properties")) {

            Properties prop = new Properties();

            if (input == null) {
                System.out.println("Sorry, unable to find config.properties");
                return;
            }

            //load a properties file from class path, inside static method
            prop.load(input);

            // Populate the data members required for all tests
            tableName = prop.getProperty("environment_list");
            tableColumn = prop.getProperty("env_name");


        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    @Test
    void fetchCMDBtable() throws Exception{
        try {
            fetchCMDB.CMDB(tableName, tableColumn);
            System.out.println("Test 1 passed");
        } catch (Exception e) {
            System.out.println("Test 1 failed!");
            e.printStackTrace();
        }
        
    }   
}

When i run the test using mvn test I get the error:

software.amazon.awssdk.core.exception.SdkClientException: Multiple HTTP implementations were found on the classpath ,

even though I have only declared the client builder once in the class.

What am i missing?

CodePudding user response：

I run the UNIT tests from the IntelliJ IDE. I find using the IDE works better then from the command line. Once I setup the

In fact - we test all Java V2 code examples in this manner to ensure they all work.

I also tested all DynamoDB examples from the command line using mvn test . All passed:

Amend your test to build a single instance of the DynamoDB client and then as your first test, make sure it was created successfully. See if this works for you. Once you get this working, add more tests!

public class DynamoDBTest {

    private static DynamoDbClient ddb;

   

    @BeforeAll
    public static void setUp() throws IOException {

        // Run tests on Real AWS Resources
        Region region = Region.US_WEST_2;
        ddb = DynamoDbClient.builder().region(region).build();
        try (InputStream input = DynamoDBTest.class.getClassLoader().getResourceAsStream("config.properties")) {

            Properties prop = new Properties();

            if (input == null) {
                System.out.println("Sorry, unable to find config.properties");
                return;
            }

            //load a properties file from class path, inside static method
            prop.load(input);

           

        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

    @Test
    @Order(1)
    public void whenInitializingAWSService_thenNotNull() {
        assertNotNull(ddb);
        System.out.println("Test 1 passed");
    }

CodePudding user response：

Turns out my pom file contained other clients, so had to remove the likes of :

       <dependency>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>s3</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>software.amazon.awssdk</groupId>
                    <artifactId>netty-nio-client</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>software.amazon.awssdk</groupId>
                    <artifactId>apache-client</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

and replaced them with :

    <dependency>
        <groupId>software.amazon.awssdk</groupId>
        <artifactId>aws-crt-client</artifactId>
        <version>2.14.13-PREVIEW</version>
    </dependency>

as mentioned in https://aws.amazon.com/blogs/developer/introducing-aws-common-runtime-http-client-in-the-aws-sdk-for-java-2-x/