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transparenterne - Objektorienteret programmering i Java

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Indkapsling og abstaktion − pak det ind i en klasse for sig<br />

Definér Databaseforbindelse−objekt og pak data ind i en specialiceret<br />

klasse, f.eks:<br />

public class Kunde<br />

{ String navn;<br />

double kredit;<br />

public Kunde(String n, double k)<br />

{ navn = n;<br />

kredit = k;<br />

}<br />

public String toString()<br />

{ return navn+": "+kredit+" kr.";<br />

}<br />

}<br />

Så kan programmet abstrahere fra hvordan data er lagret<br />

import java.util.*;<br />

public class BenytDatabaseforbindelse<br />

{ public static void main(String arg[])<br />

{ try {<br />

Databaseforbindelse dbf = new Databaseforbindelse();<br />

// dbf.opretTestdata(); // sæt ind hvis tabellen ikke findes<br />

Vector v = dbf.hentAlle();<br />

System.out.println("Alle data: "+v);<br />

dbf.sletAlleData();<br />

dbf.indsæt( new Kunde("Kurt",1000) );<br />

} catch(Exception e) {<br />

System.out.println("Problem med database: "+e);<br />

e.printStackTrace();<br />

}<br />

}<br />

}<br />

Alle data: [Kurt: 1000.0 kr.]

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