顯示選取數字

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class button implements ActionListener
{

public static void main(String[] args)
{new button();}

public button(){
JButton jbnButton[]=new JButton[17];
JFrame jtfMainFrame = new JFrame("愛翹課");
jtfMainFrame.setSize(450, 450);
JPanel jplPanel = new JPanel();

//使用GridLayout在Panel裡面切出4x4的格子，使按鈕排整齊
jplPanel.setLayout(new GridLayout(4,4));

for(int i=1;i<17;i++){
jbnButton[i]=new JButton();
jbnButton[i].setSize(50, 50);
jbnButton[i].setText(Integer.toString(i));
jbnButton[i].setActionCommand(""+i);
jbnButton[i].addActionListener(this);
jplPanel.add(jbnButton[i]);
}
jtfMainFrame.getContentPane().add(jplPanel, BorderLayout.CENTER);
//把Panel加進去Fram
jtfMainFrame.setVisible(true); //讓Fram顯示出來
}

public void actionPerformed(ActionEvent e) {
String cmd = e.getActionCommand();JOptionPane.showMessageDialog(null,"此數字為"+cmd); }

}

不重複陣列

import java.io.*;
import javax.swing.*;
import java.awt.*;
import java.util.Arrays;

public class button
{
  public static void main(String[] args) throws IOException
  {
    JFrame frame = new JFrame("作業GridLayout)");
    GridLayout f1=new GridLayout(4, 13);

    Container c=frame.getContentPane();

    c.setLayout(f1);
   
    int [] num = new int[16]; //宣告一個數字陣列，用來記錄產生過的亂數
    Arrays.fill(num,-1); //將陣列內容全都設為-1
    int i=1;
    do{
      int j=(int)(Math.random()*16);
      if(num[j] == 0) continue; //判斷是否亂數取出的數字是否出現過
      num[j] = 0;//將出現過的數字索引值的陣列內容設為0，代表出現過
      c.add(new JButton("第"+j+"個"));
      i++;
    }while(i<=16);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(300,300);
    frame.setVisible(true);
  }
}

顯示資料

import java.net.*;

public class TestInet1 {
  public static void main(String argv[]) 
  {
    try {
      InetAddress myip = InetAddress.getLocalHost();

      System.out.println(myip.getHostName());
      System.out.println(myip.getHostAddress());
    } catch (UnknownHostException e) {
      System.out.println("Error: unable to resolve localhost");
    }
  }
}