Array “out of bounds” [duplicate]

问题

This question already has answers here:

What is a stack trace, and how can I use it to debug my application errors? (7 answers)

How do I declare and initialize an array in Java? (24 answers)

Closed 5 years ago.

I'm using an array of String[3] to store user input which is got from 4 JTextFields I then output the array to a txt file:

String[] userInfo = new String[3];
    userInfo[0] = sourceTextField.getText();
    userInfo[1] = usernameTextField.getText();
    userInfo[2] = passwordTextField.getText();
    userInfo[3] = emailTextField.getText();
    for (String userInfo1 : userInfo) {
        try 
        {
            BufferedWriter writer = new BufferedWriter(new FileWriter("C:\\Users\\Peace Infinity\\Desktop\\[programming]Projects\\DataFiles\\PasswordRepository.txt", true));
            String s;
            s = userInfo1;
            writer.write(s + " ");
            writer.flush();
        }catch (IOException ex) 
        {
            Logger.getLogger(ADD_dialogBox_v1.class.getName()).log(Level.SEVERE, null, ex);
            JOptionPane.showMessageDialog(null, "Error processing file!");
        }
    }

Can someone tell me why I'm getting exception "array index out of bounds"? Thank you

回答1:

When you declare an array you provide the length/size of that array. An array starts at index 0 as you've done in your code, but you're trying to assign a value to an index "out of bounds" - the fourth index.

new String[3] // index 0,1,2
new String[4] // index 0,1,2,3

回答2:

solution is very simple

String[] userInfo = new String[4];

回答3:

You are using a smaller Array.... do this

String[] userInfo = new String[4];

I would suggest you to use Arraylist as this does not require any size to declare and can accomodate any number of items.

  ArrayList<String> userInfo = new ArrayList<>();
    userInfo.add(sourceTextField.getText());
    userInfo.add(usernameTextField.getText());
    userInfo.add(passwordTextField.getText());
    userInfo. dd(emailTextField.getText());
     for (String userInfo1 : userInfo) {
        try 
        {.......
           ............

And the rest of the code proccessed accordingly....

来源：https://stackoverflow.com/questions/25983096/array-out-of-bounds

标签

java

arrays

jtextfield

filewriter

bufferedwriter