Question

I am a newbie to Java, My problem is I am trying to insert currency rates into my MySQL database table called currency which contains two columns Currency_name and rate. The program fetches currency rate from finance yahoo API, I am facing The problem of storing the data into my database.

void checkRateAllAtEnd() throws Exception {
       /** print message  */
    System.out.println("checkRateAllAtEnd :");
        long start = System.nanoTime();

        List<Callable<HashMap>> tasks = new ArrayList<Callable<HashMap>>();
        for (final String ccy : CURRENCY) {
                tasks.add(new Callable<HashMap>() {
                        public HashMap call() throws Exception {
                                return getRates(ccy);
                        }
                });
        }
        ExecutorService executorPool = Executors.newCachedThreadPool();
        final List<Future<HashMap>> listRates = executorPool.invokeAll(tasks, 3600, TimeUnit.SECONDS);

        for (Future<HashMap> rate : listRates) {
                HashMap ccyRate = rate.get();
                System.out.println("Value of £1 in " + ccyRate.get("CCY") + " is " + ccyRate.get("RATE"));
        }

I am lacking the credit to pass the values from hashmap to preparedStatement.

        String sql="update currency set currency_name='"+Value1+"'";
        preparedstatement=connection.prepareStatement(sql); 
        preparedstatement.execute();

I have the entire class here on this link fully functioning to keep the question clean >>linke<<<

this is the output of the programe which i would like to store into MYSQL Ideally i would like to store

ccyRate.get(“CCY”) and ccyRate.get(“RATE”)

checkRateAllAtEnd :
Value of £1 in AED is 5.9201
Value of £1 in AFN is 82.4359
Value of £1 in ALL is 171.681
Value of £1 in AMD is 650.4296
Value of £1 in ANG is 2.8849
Value of £1 in AOA is 154.4766
Value of £1 in ARS is 7.9438
Value of £1 in AUD is 1.5345

Answer 1

Your addCurrency method is wrong – Not only you’re not gaining anything by providing the preparedStatmenet as parameter , you’re not gaining anything when trying to close it,
as it is null at that point.
Please show us the exact error/exception you’re having and I’ll edit my answer accordingly.