小编Use*_*ser的帖子

我是java的初学者.我JPanel在java(NetBeans)中创建了一个表单.然后,我定义了一些动作,如数学计算.当我运行我的项目时,我没有收到任何错误,但我JPanel在运行时看不到表单.因为我没有在主类中定义jform.如何JPanel在主类中定义表单JPanel以在运行时向我显示表单.

public class NewJPanel extends javax.swing.JPanel {


    public NewJPanel() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();
        jTextField2 = new javax.swing.JTextField();
        jTextField3 = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();
        jButton4 = new javax.swing.JButton();
        jButton5 = new javax.swing.JButton();

        jLabel1.setText("First Number:");

        jLabel2.setText("Second Number:");

        jLabel3.setText("Result:");

        jButton1.setText("Add"); …

我在书中看到了下面的代码.我知道void方法不能返回值.当我运行代码时,编译器无法打印修改后的数组,而在本书中,会显示值.如何修复代码以打印修改后的数组？

public static void main(String[] args) {

    int[] array = {1, 2, 3, 4, 5};
    System.out.println("The values of original array are:");
    for(int value: array)
    {
        System.out.print(value + "\t");
    }
    modifyArray(array);
    System.out.println("The values after modified array are:");
    for (int value:array)
    {
        System.out.print(value + "\t");
    }

}    
public static void modifyArray(int[] b)
{
    for (int counter=0; counter<=b.length; counter++)
    {
        b[counter] *=2; 
    }
}