package src;
 
public class Application {
 public static void main(String[] args) {
 WindowBoxLayout win=new WindowBoxLayout();
 win.setBounds(100,200,300,350);
 win.setTitle("随机数生成器");
 win.setVisible(true);
 }
}

package src;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
 
import javax.swing.*;
 
public class RandomListener implements ActionListener{
 JTextField text1;
 JTextArea text2;
 Random random=new Random();
 int result=0;
 public void setJTextField(JTextField t){
 text1=t;
 }
 public void setJTextArea(JTextArea t){
 text2=t;
 }
 @Override
 public void actionPerformed(ActionEvent e) {
 try{
 text2.setText("");
 Integer number=Integer.parseInt(text1.getText());
 result=random.nextInt(number)+1;
 text2.append(result+"");
 }
 catch(Exception exp){
 text2.append("请输入数字字符");
 
 }
 }
}

package src;
 
import javax.swing.*;
public class WindowBoxLayout extends JFrame{
 /**
 * 
 */
 private static final long serialVersionUID = 1L;
 Box baseBox;
 JTextField text1;
 JTextArea text2;
 JButton button;
 RandomListener random;
 public WindowBoxLayout(){
 setLayout(new java.awt.FlowLayout());
 init();
 setVisible(true);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }
 void init(){
 baseBox=Box.createVerticalBox();
 baseBox.add(new JLabel("请输入随机数的最大范围值："));
 baseBox.add(Box.createVerticalStrut(8));
 text1=new JTextField(5);
 baseBox.add(text1);
 baseBox.add(Box.createVerticalStrut(8));
 button=new JButton("确定");
 baseBox.add(Box.createVerticalStrut(8));
 baseBox.add(button);
 text2=new JTextArea(6,12);
 baseBox.add(Box.createVerticalStrut(18));
 baseBox.add(text2);
 add(baseBox);
 random=new RandomListener();
 random.setJTextField(text1);
 random.setJTextArea(text2);
 button.addActionListener(random);
 }
 
}