Creating XML from the data present in the dataSet

Question

1. I have the following data… in the form of Years and Months in my resultSet and I want to remove redundant years and months to create xml elements as:

   [2015, 2016, 2017] [05, 06, 07, 08, 09, 10, 11, 12, 01, 02, 03, 04]

and I am trying to generate XML Tags out of this data Year and Month wise as:

<Root>
<Year Y="2015">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
<Year Y="2016">
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
<Year Y="2017">
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
</Year>
</Root>

But the output I am getting is as:

<Root>
<Year Y="2015">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/> 
<Month M="03"/>
<Month M="04"/>
</Year>
<Year Y="2016">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
</Year>
<Year Y="2017">
<Month M="05"/>
<Month M="06"/>
<Month M="07"/>
<Month M="08"/>
<Month M="09"/>
<Month M="10"/>
<Month M="11"/>
<Month M="12"/>
<Month M="01"/>
<Month M="02"/>
<Month M="03"/>
<Month M="04"/>
</Year>
</Root>

That is how I am tackling my problem

try{
            //Connection
        connection = DriverManager.getConnection(conUrl);
        statement = connection.createStatement();
        resultSet = statement.executeQuery(query);

            //XML 
        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
        Document document = documentBuilder.newDocument();

            // Super Root Node (Necessity)
        Element necessaryElement = document.createElement("Root");
        document.appendChild(necessaryElement);

        while(resultSet.next()){
            //Year Array populating
            monitoringYear  = resultSet.getString("Year");
            monitoringYearArray.add(monitoringYear);

            //Month Array populating
            monitoringMonth = resultSet.getString("Month");
            System.out.println( "Monitoring Month "+ monitoringMonth);

            monitoringMonthArray.add(monitoringMonth);

        }

                    // remove duplicate from the Years ArrayList and retain the order
                Set<String> uniqueYearList = new LinkedHashSet<String>(monitoringYearArray);
                monitoringYearArray.clear();
                monitoringYearArray.addAll(uniqueYearList); 

                // Remove duplicate from the Month ArrayList and retain the order
                Set<String> uniqueMonthList = new LinkedHashSet<String>(monitoringMonthArray);
                monitoringMonthArray.clear();
                monitoringMonthArray.addAll(uniqueMonthList);

                    // XML Element for the Year
                for(int year = 0; year < monitoringYearArray.size(); year++){
                        // Super Root Node (Year)
                    Element yearElement = document.createElement("Year");
                    necessaryElement.appendChild(yearElement);

                    Attr yearAttr = document.createAttribute("Y");
                    yearAttr.setValue(monitoringYearArray.get(year));
                    yearElement.setAttributeNode(yearAttr);

                            // XML Element for the Month
                        for(int month = 0; month < monitoringMonthArray.size(); month++){

                                // Sub Root Node (Month)
                            Element monthElement = document.createElement("Month");
                            yearElement.appendChild(monthElement);

                            Attr monthAttr = document.createAttribute("M");
                            monthAttr.setValue(monitoringMonthArray.get(month));
                            monthElement.setAttributeNode(monthAttr);

                        }
                }

If you have any suggestions how to solve the problem, i would greatly appreciate Thanks

Answer 1

I think it is use of Set Object and while loop in one level that overwrites the months If you'd like to keep all the values a key is given, you might consider implementing like apache.commons.collections.MultiHashMap or

HashMap<String, LinkedHashSet> monthsincludedmap = new HashMap<String, LinkedHashSet >();

check Difference between HashSet and HashMap?

What happens when a duplicate key is put into a HashMap?