Simple Export and Import of a Sqlite Database on Android

import/export to android sqlite database

SQlite database to our local file system-

Function declaration-

        try {
            backupDatabase();
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

Function defined-

public static void backupDatabase() throws IOException {
        //Open your local db as the input stream
        String inFileName = "/data/data/com.myapp.main/databases/MYDB";
        File dbFile = new File(inFileName);
        FileInputStream fis = new FileInputStream(dbFile);

        String outFileName = Environment.getExternalStorageDirectory()+"/MYDB";
        //Open the empty db as the output stream
        OutputStream output = new FileOutputStream(outFileName);
        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = fis.read(buffer))>0){
            output.write(buffer, 0, length);
        }
        //Close the streams
        output.flush();
        output.close();
        fis.close();
    }

simple import/export option of a sqlite database

Try this:

private void importDatabase(String inputFileName) throws IOException
{
    InputStream mInput = new FileInputStream(inputFileName);
    String outFileName = YOUR_DB_PATH_HERE;
    OutputStream mOutput = new FileOutputStream(outFileName);
    byte[] mBuffer = new byte[1024];
    int mLength;
    while ((mLength = mInput.read(mBuffer))>0)
    {
        mOutput.write(mBuffer, 0, mLength);
    }
    mOutput.flush();
    mOutput.close();
    mInput.close();
}

How to remove duplicate and sort objects from JSONArray using Java

I wrote this utility a while ago, it sorts a JSONArray of JSONObjects
Only condition is that your JSONobjects must contain the keys you want to sort based on (it also accept a set of keys if you want to sort based on several keys)

import java.util.Collections;
import java.util.Comparator;
import java.util.Random;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class JSONArraySort {
    @SuppressWarnings("unchecked")
    public static void sortASCE(JSONArray array, Object key) {
        Object[] keys = { key };
        Collections.sort(array, new JSONArrayComparator(false, keys));
    }
    @SuppressWarnings("unchecked")
    public static void sortDESC(JSONArray array, Object key) {
        Object[] keys = { key };
        Collections.sort(array, new JSONArrayComparator(true, keys));
    }
    @SuppressWarnings("unchecked")
    public static void sortASCE(JSONArray array, Object[] key) {
        Collections.sort(array, new JSONArrayComparator(false, key));
    }
    @SuppressWarnings("unchecked")
    public static void sortDESC(JSONArray array, Object[] key) {
        Collections.sort(array, new JSONArrayComparator(true, key));
    }
    private static class JSONArrayComparator implements Comparator<JSONObject> {
        private final Object[] KEYS;
        private final boolean DESC;
        public JSONArrayComparator(boolean DESC, Object[] KEYS) {
            this.KEYS = KEYS;
            this.DESC = DESC;
        }
        @Override
        public int compare(JSONObject object1, JSONObject object2) {
            int length = KEYS.length;
            for(int i = 0 ; i < length ; i++){
                String KEY = KEYS[i].toString();
                Object one = object1.get(KEY);
                Object two = object2.get(KEY);
                if(Number.class.isAssignableFrom(one.getClass()) && Number.class.isAssignableFrom(two.getClass())){
                    Double numOne = Number.class.cast(one).doubleValue();
                    Double numTwo = Number.class.cast(two).doubleValue();
                    int compared = 0;
                    if(DESC){
                        compared = numTwo.compareTo(numOne);
                    }else{
                        compared = numOne.compareTo(numTwo);
                    }
                    if(i == KEYS.length - 1 || compared != 0){
                        return compared;
                    }
                }else{
                    int compared = 0;
                    if(DESC){
                        compared = two.toString().compareTo(one.toString());
                    }else{
                        compared = one.toString().compareTo(two.toString());
                    }
                    if(i == KEYS.length - 1 || compared != 0){
                        return compared;
                    }
                }
            }
            // this shouldn't happen.
            return 0;
        }
    }
        //testing...
    public static void main(String... args) {
        JSONArray array1 = new JSONArray();
        for(int i = 0 ; i < 100 ; i++){
            Random random = new Random();
            int num1 = random.nextInt(10);
            int num2 = random.nextInt(10);
            JSONObject object = new JSONObject();
            object.put("num1", num1);
            object.put("num2", num2);
            array1.add(object);
        }
        String[] keys = { "num1", "num2" };
        sortASCE(array1, keys);
        System.out.println(array1.toString());
    }
}

now if you want to remove duplicates you can iterate through them

Set<String> stationCodes=new HashSet<String>();
JSONArray tempArray=new JSONArray();
for(int i=0;i<yourJSONArray.size();i++){
   String  stationCode=yourJSONArray.getJSONObject(i).getString("stationCode");
   if(stationsCodes.contains(stationCode){
     continue;
   }
   else{
      stationsCodes.add(stationCode);
      tempArray.add(yourJSONArray.getJSONObject(i));
   }

}


yourJSONArray= tempArray; //assign temp to original

//here how you can sort it using utility above:
JSONArraySort.sortASCE(yourJSONArray,"distance");

How to remove duplicate objects from json array using hashset?

Below code parses your json and puts it in the HashMap to get unique elements

    HashMap<String,String> hashOut = new HashMap<String,String>();
    String input = "{\"others\":[    {        \"id\":\"1\",        \"caption\":\"test\"    },    {        \"id\":\"2\",        \"caption\":\"self\"    },    {        \"id\":\"2\",        \"caption\":\"self\"    },    {        \"id\":\"1\",        \"caption\":\"test\"    }],\"quantity\":[    {        \"id\":\"1\",        \"caption\":\"self1\"    },    {        \"id\":\"1\",        \"caption\":\"self1\"    }]}";
    JSONObject jsonObj = new JSONObject(input);
    Iterator it = jsonObj.keys();

    while (it.hasNext()) {
        hashOut.clear();
        JSONArray jsInner = (JSONArray) jsonObj.getJSONArray((String) it.next());
        for (int i=0;i<jsInner.length();i++) {
            JSONObject jo = new JSONObject(jsInner.get(i).toString());
            hashOut.put((String)jo.get("id"), (String)jo.get("caption"));
        }
        System.out.println(hashOut);
    }

To get the output as below

{2=self, 1=test}
{1=self1}

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