Trying to copy data from a file to an array but it gives me error

Hi I am new on programing and I am having a problem I am trying to copy some things from a file to a array and I just want to copy in the position 1,2,3 and 4 from the file. Example copy to the array 11 , G , 0 , 20.

FILE TEXT:
0;11;G;0;200;1
2;10;F;0;300;2
0;12;J;0;100;3

String[][] aa = new String[100][6];
try {
    Scanner x = new Scanner(new File("Turmas.txt"));
    x.useDelimiter("[;n]");

    for (int i = 0; i < 100; i++) {
        for (int j = 0; j < 6; j++) {
            if (x.hasNext()) {
                aa[i][j] = x.next();
            }
        }
    }
    x.close();
} catch (FileNotFoundException ex) {
    JOptionPane.showMessageDialog(
        null, "An error occurred, try restarting the program!", 
        "ERROR!", JOptionPane.ERROR_MESSAGE
    );
}

String[][] aaa = new String[100][4];
for (int i = 0; i < 100; i++) {
    for (int j = 0; j < 4; j++) {
        if (aa[i][j] == null) {
            System.out.println("null "  + i + "  " + j);
        }
        else {
            if (aa[i][0].equals(String.valueOf(SAVEID))) {
                aaa[i][j]     = aa[i][1];
                aaa[i][j + 1] = aa[i][2];
                aaa[i][j + 2] = aa[i][3];
                aaa[i][j + 3] = aa[i][4];
            }
        }
    }
}
System.out.println(aaa[0][0]);
System.out.println(aaa[0][1]);
System.out.println(aaa[0][2]);
System.out.println(aaa[0][3]);

ERROR:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 4
    at Lista_Sumarios.ListarTurmas.btnUpdateMouseClicked(ListarTurmas.java:780)
    at Lista_Sumarios.ListarTurmas.access$2500(ListarTurmas.java:33)
    at Lista_Sumarios.ListarTurmas$11.mouseClicked(ListarTurmas.java:424)
    at java.awt.Component.processMouseEvent(Component.java:6536)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6298)
    at java.awt.Container.processEvent(Container.java:2236)
    at java.awt.Component.dispatchEventImpl(Component.java:4889)
    at java.awt.Container.dispatchEventImpl(Container.java:2294)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4534)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
    at java.awt.Container.dispatchEventImpl(Container.java:2280)
    at java.awt.Window.dispatchEventImpl(Window.java:2746)
    at java.awt.Component.dispatchEvent(Component.java:4711)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Answer

If only 4 values are needed from the input array are needed, why not just read these specific values?

String[] result = new String[4];

try (Scanner input = new Scanner(new File("Turmas.txt")) // input closed automatically
    .useDelimiter(";|\R")  // use character class R to match line-feed characters 
) {
    if (input.hasNext()) {
        input.next(); // skip the 1st token

        for (int i = 0; i < result.length && input.hasNext(); i++) {
            result[i] = input.next();
        }
    }
} catch (FileNotFoundException ex) {
    JOptionPane.showMessageDialog(
        null, "An error occurred, try restarting the program!", 
        "ERROR!", JOptionPane.ERROR_MESSAGE
    );
}

If it is needed to read the columns with indexes [1..4] from the file containing 6 columns per line, it is cleaner to read the source file line by line, split each line by ;, skip 1 column with index 0, and keep the 4 columns.

String[][] result = new String[100][4];

try (Scanner input = new Scanner(new File("Turmas.txt"))) {
    for (int i = 0; i < result.length && input.hasNextLine(); i++) {
        String[] parts = input.nextLine().split(";");
        for (int j = 1; j < Math.min(result[i].length, parts.length); j++) {
            result[i][j - 1] = parts[j];
        }
    }    
} catch (FileNotFoundException ex) {
    JOptionPane.showMessageDialog(
        null, "An error occurred, try restarting the program!", 
        "ERROR!", JOptionPane.ERROR_MESSAGE
    );
}

Advertisement

Answer