Merge two XML files in java and make single xml

Question

Suppose a class Output.java contains 6 varibles, out of which 4 variables data is stored on database_A and 2 variable data is stored in database_B.

My class Delegate.java need to communicate with two diffrent service Service_A.java and Service_B.java which will ask database_A and database_B respectively to fetch respective data (database_A - 4 varibales, database_B - 2 variables).

The communication between Delegate.java and Service_A.java/Service_B.java is in form of XML request/response.

So Deleage.java will have two XML as response, one from database_A (called by Service_A.java) and one from database_b (called by Service_B.java).

I want to merge these two XML files and make a singe XML file Final_xml, which contains valuse of all 6 variables of Output.java class.

Answer 1

You can consider XML as text file and combine them. That is very fast as compared to other methods. Please have a look at below code :-

import java.io.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class XmlComb {

    static Set<String> lstheader = new HashSet<String>();

    public static void main(String[] args) throws IOException {
        Map<String,List<String>> map1 = getMapXml("J:\\Users\\Documents\\XMLCombiner01\\src\\main\\resources\\File1.xml");
        Map<String,List<String>> map2 = getMapXml("J:\\Users\\Documents\\XMLCombiner01\\src\\main\\resources\\File2.xml");
        Map<String,List<String>> mapCombined = combineXML(map1, map2);

        lstheader.forEach( lst -> {
            System.out.println(lst);
        });

        try {
            mapCombined.forEach((k,v) -> {

                System.out.println(k);
                v.forEach(val -> System.out.println(val));


            });
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static Map<String,List<String>> combineXML(Map<String, List<String>> map1, Map<String, List<String>> map2 ) {

        Map<String,List<String>> map2Modified = new TreeMap<String, List<String>>();
        Map<String,List<String>> mapCombined = new TreeMap<String, List<String>>();
        // --- Modifying map ---
        for(String strKey2 : map2.keySet()) {

            if(map1.containsKey(strKey2)) {
                map2Modified.put(strKey2.split("\">")[0] + "_1\">", map2.get(strKey2));
            }
            else {
                map2Modified.put(strKey2 , map2.get(strKey2));
            }
        }   

        //---- Combining map ---

        map1.putAll(map2Modified);

        return map1;
    }


    public static Map<String,List<String>> getMapXml(String strFilePath) throws IOException{
        File file = new File(strFilePath);

        BufferedReader br = new BufferedReader(new FileReader(file));
        Map<String, List<String>> testMap = new TreeMap<String, List<String>>();
        List<String> lst = null;

        String st;
        String strCatalogName = null;
        while ((st = br.readLine()) != null) {
            //System.out.println(st);
            if(st.toString().contains("<TestCase")){
                lst = new ArrayList<String>();
                strCatalogName = st;
                testMap.put(strCatalogName, lst);
            }
            else if(st.contains("</TestCase")){
                lst.add(st);
                testMap.put(strCatalogName,lst);
            }
            else {
                if(lst != null){
                    lst.add(st);
                }else {
                    lstheader.add(st);
                }

            }

        }

        return testMap;
    }
}

Answer 2

Yes its possible to merge xml files. You can refer below links to merge your file. Do necessary changes in code of below links to achieve structure of your XML. If possible share structure of your XML , will help you with the relevant code.

Merge Two XML Files in Java

Merging xml file using java NodeList