MySQL.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.function.Consumer;
import java.util.function.Function;

public class MySQL {

	private static Connection conn;

	  public void connect(String host, String database, int port, String user, String password){
	        if(!isConnected()){
	            try {
	                conn = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + database, user, password);
	                System.out.println("Connexion etablie avec la base de donnees");
	            } catch (SQLException e) {
	                e.printStackTrace();
	                System.out.println("Connexion refuse avec la base de donnees");
	            }
	        }
	    }

	    public void disconnect(){
	        if(isConnected()){
	            try {
	                conn.close();
	            } catch (SQLException e) {
	                e.printStackTrace();
	            }
	        }
	    }

	    public static Connection getConnection(){
	        return conn;
	    }

    public void update(String qry){
        try {
             PreparedStatement s = getConnection().prepareStatement(qry);
            s.executeUpdate();
        } catch(Exception e){
            e.printStackTrace();
        }
    }

    public Object query(String qry, Function<ResultSet, Object> consumer){
        try {
            PreparedStatement s = getConnection().prepareStatement(qry);
            ResultSet rs = s.executeQuery();
            return consumer.apply(rs);
        } catch(SQLException e){
            throw new IllegalStateException(e.getMessage());
        }
    }

    public void query(String qry, Consumer<ResultSet> consumer){
        try {
             PreparedStatement s = getConnection().prepareStatement(qry);
             ResultSet rs = s.executeQuery();
            consumer.accept(rs);
        } catch(SQLException e){
            throw new IllegalStateException(e.getMessage());
        }
    }

    public boolean isConnected(){
        try {
            if((conn == null) || (conn.isClosed()) || (conn.isValid(5))){
                return false;
            }
            return true;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

}