@InvokeOnHeader(Web3jConstants.DB_GET_STRING)
    void dbGetString(Message message) throws IOException {
        String databaseName = message.getHeader(Web3jConstants.DATABASE_NAME, configuration::getDatabaseName, String.class);
        String keyName = message.getHeader(Web3jConstants.KEY_NAME, configuration::getKeyName, String.class);
        Request<?, DbGetString> request = web3j.dbGetString(databaseName, keyName);
        setRequestId(message, request);
        DbGetString response = request.send();
        boolean hasError = checkForError(message, response);
        if (!hasError) {
            message.setBody(response.getStoredValue());
        }
    }
@Test
    public void dbGetStringTest() throws Exception {
        DbGetString response = Mockito.mock(DbGetString.class);
        Mockito.when(mockWeb3j.dbGetString(any(), any())).thenReturn(request);
        Mockito.when(request.send()).thenReturn(response);
        Mockito.when(response.getStoredValue()).thenReturn("test");

        Exchange exchange = createExchangeWithBodyAndHeader(null, OPERATION, Web3jConstants.DB_GET_STRING);
        template.send(exchange);
        String body = exchange.getIn().getBody(String.class);
        assertEquals("test", body);
    }