How do I store an arraylist?

Question

I am trying to store my ArrayList between runtimes. So when I enter items into the ArrayList then close the program down and then open it back up and try to search the item I put in it will still be there.

I have tried MySQL and XML but I cannot figure it out. If you could please direct me in the direction of an easy way to store ArrayList that would be amazing.

Edit:

I am trying to serialize this ArrayList :

static ArrayList<Product> Chart=new ArrayList<Product>();

with these objects:

double Total;
String name;
double quantity;
String unit;
double ProductPrice;

Answer 1

Look into object serialization, it sounds like exactly what you want

What is object serialization?

This allows you to write a Java object to a file and read it back in later.

Answer 2

Here is an example. It also zips up the file, although you don't have to do that. You can also use the stream to write to a MYSQL blob instead of a file.

public static <T> void writeToGZIP(String filename, T obj) {
    ObjectOutputStream os = null;

    try {
        os = new ObjectOutputStream(new GZIPOutputStream(new FileOutputStream(filename)));
        os.writeObject(obj);                    
        System.out.println("Object written to " + filename);
    } catch (Exception e) {         
        e.printStackTrace();            
    } finally {
        try {
            if (os != null) { os.flush(); os.close(); }
        } catch (IOException e) {           
            e.printStackTrace();
        }
    }       
}

@SuppressWarnings("unchecked")
public static <T> T readFromGZIP(String filename, T obj) {      
    ObjectInputStream ois = null;       

    try {
        ois = new ObjectInputStream(new GZIPInputStream(new FileInputStream(filename)));            
        obj = (T) ois.readObject();         
    } catch (Exception e) {         
        e.printStackTrace();            
    } finally { 
        try {
            if( ois != null ) ois.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    return obj;
}

Answer 3

ObjectOutputStream和ObjectInputStream