I have a problem in my aplication trying to deserialize a ArrayList of String from a Blob in a SQLite DataBase. I reached to serialize the array and save it in the Database but I could not recover it as it should be. I think the problem is when deserializing because I manage to recover the strings but all within the same array element run. This is the deserializing method
private static ArrayList<String> sqliteBytesToArrayListString(ResultSet results){
ArrayList<String> acciones = new ArrayList<String>();
try {
byte[] asBytes = results.getBytes("actions");
ByteArrayInputStream bin = new ByteArrayInputStream(asBytes);
BufferedReader din = new BufferedReader(new InputStreamReader(bin));
for (int i = 0; i < asBytes.length/16; i++)
acciones.add(din.readLine());
} catch (SQLException e) {
System.out.println("There was a problem converting bytes[] to ArrayList in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
} catch (IOException e) {
System.out.println("There was a problem converting bytes[] to ArrayList in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
return acciones;
}
Here I leave my complete code
package BDD;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
public class DataBase {
private final static String BDD_URL = "jdbc:sqlite:grabadora.db";
private final static String SCRIT_INSERT = "INSERT INTO test (recordName, actions) VALUES (?, ?);";
private final static String SCRIT_SELECT_ALL = "SELECT * FROM test;";
private final static String SCRIPT_TABLE =
"CREATE TABLE IF NOT EXISTS test (recordId INTEGER PRIMARY KEY AUTOINCREMENT, recordName TEXT, actions BLOB);";
public static void main(String[] args) throws SQLException {
ArrayList<String> datos = new ArrayList<>();
datos.add("Second");
datos.add("Third");
datos.add(0, "First");
String name = "record2";
Connection con = DataBase.getConnection();
DataBase.createTable(con);
DataBase.addNewRecord(name, datos, con);
con.close();
System.out.print(DataBase.getRecords());
}
public static void addNewRecord(String nombre, ArrayList<String> acciones, Connection con){
try {
PreparedStatement stat = con.prepareStatement(SCRIT_INSERT, Statement.RETURN_GENERATED_KEYS);
stat.setString(1, nombre);
stat.setBytes(2, arrayListToBytes(acciones));
stat.executeUpdate();
ResultSet res = stat.getGeneratedKeys();
while(res.next()){
System.out.println(res.getInt(1) + "\t" );
}
stat.close();
res.close();
} catch (SQLException e) {
System.out.println("There was a problem doing the update in the method | " + e.getMessage() + " | " + e.getSQLState()+ " | " + e.toString());
e.printStackTrace();
}
}
public static String getRecords(){
Connection con = DataBase.getConnection();
String Records="";
try{
Statement sta = con.createStatement();
ResultSet results = sta.executeQuery(SCRIT_SELECT_ALL);
while(results.next()){
int id = Integer.parseInt(results.getString("recordId"));
String nombre = results.getString("recordName");
ArrayList<String> actionsArray = sqliteBytesToArrayListString(results);
String print = "\n RecordId= " + id + " | RecordName= " + nombre + " | Actions= " + Arrays.toString(actionsArray.toArray()) ;
Records += print;
}
con.close();
sta.close();
}catch(SQLException e){
System.out.println("There was a problem al obtener las grabaciones in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
return Records;
}
private static ArrayList<String> sqliteBytesToArrayListString(ResultSet results){
ArrayList<String> acciones = new ArrayList<String>();
try {
byte[] asBytes = results.getBytes("actions");
ByteArrayInputStream bin = new ByteArrayInputStream(asBytes);
BufferedReader din = new BufferedReader(new InputStreamReader(bin));
for (int i = 0; i < asBytes.length/16; i++)
acciones.add(din.readLine());
} catch (SQLException e) {
System.out.println("There was a problem converting bytes[] to ArrayList in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
} catch (IOException e) {
System.out.println("There was a problem converting bytes[] to ArrayList in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
return acciones;
}
private static byte[] arrayListToBytes(ArrayList<String> array){
byte[] dataInBytes= new byte[1];
try {
ByteArrayOutputStream byteOutput = new ByteArrayOutputStream();
DataOutputStream dataOutput = new DataOutputStream(byteOutput);
for (String element: array)
dataOutput.writeBytes(element);
dataOutput.close();
dataInBytes = byteOutput.toByteArray();
} catch (IOException e) {
System.out.println("There was a problem converting the ArrayList in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
return dataInBytes;
}
private static Connection getConnection() {
Connection conn = null;
try {
Class.forName("org.sqlite.JDBC");
conn = DriverManager.getConnection(BDD_URL);
System.out.println("Connection created successfully");
} catch (ClassNotFoundException e) {
System.out.println("There was a problem creating the connection in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
} catch (SQLException e){
System.out.println("There was a problem creating the connection in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
return conn;
}
private static void createTable(Connection conexion){
try {
Statement stat = conexion.createStatement();
stat.executeUpdate(SCRIPT_TABLE);
stat.close();
System.out.println("The table was created or already exists");
} catch (SQLException e) {
System.out.println("There was a problem creating the table in the method | " + e.getMessage() + " | " + e.toString());
e.printStackTrace();
}
}
}
I base myself on this answer about to store a ArrayList in sql
And I use this tool to se the use this tool to view my database data I got this results
