file2.txt

用JAVA编写的在线考试系统

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class computor
{
	private JFrame jf = null;
	private JButton jbadd, jbsub, jbmutil, jbdiv, jbequal, jbdot, jbcr;
	private JTextField jexpression;
	private JButton jb[] = new JButton[10];
	private Font newfnt;
	private Font oldfnt;
		public computor(){
			newfnt = new Font(null, Font.BOLD, 30);
         		jexpression = new JTextField("");
        jexpression.setHorizontalAlignment(JTextField.RIGHT);		
			for(int index=0; index<10; index++)
		{
			jb[index] = new JButton(index+"");
			jb[index].addActionListener(new ExpressionButtonHandler());
			jb[index].addMouseListener(new EnterOutHandle());
		}
		
		oldfnt = jb[0].getFont();
		
		jbequal = new JButton("=");
		jbequal.addActionListener(new ResultButtonHandler());
		//jbequal.setFont(fnt);
		
		jbdot  = new JButton("."); 
		jbdot.addActionListener(new ExpressionButtonHandler());
		//jbdot.setFont(fnt);
		
		jbadd = new JButton("+");
		jbadd.addActionListener(new ExpressionButtonHandler());	
		//jbadd.setFont(fnt);			
		
		jbsub = new JButton("-");
		jbsub.addActionListener(new ExpressionButtonHandler());	
		//jbsub.setFont(fnt);		
				
		jbmutil = new JButton("*");
		jbmutil.addActionListener(new ExpressionButtonHandler());	
		
		//jbmutil.setFont(fnt);		
				
		jbdiv = new JButton("/");		
		jbdiv.addActionListener(new ExpressionButtonHandler());	
		//jbdiv.setFont(fnt);		
				
		jbcr = new JButton("CR");
		jbcr.addActionListener(new CRButtonHandler());				
		//jbcr.setFont(fnt);
		/////////////////////////////////////////////////////////////////////		
		
		jf = new JFrame();
    jf.setTitle("Swing计算器");
    jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    jf.setSize(400, 200);
    jf.setLocation(100, 200);
    jf.setLayout(new BorderLayout()); //总体布局
   
   
    JPanel jptop = new JPanel(new GridLayout(1,2));
    jptop.add(jexpression);
    jptop.add(jbcr);
       
    JPanel jpdown = new JPanel(new GridLayout(4,4));
    jpdown.add(jb[1]);
    jpdown.add(jb[2]);
    jpdown.add(jb[3]);
    jpdown.add(jbadd);
    jpdown.add(jb[4]);
    jpdown.add(jb[5]);
    jpdown.add(jb[6]);
    jpdown.add(jbsub);
    jpdown.add(jb[7]);
    jpdown.add(jb[8]);
    jpdown.add(jb[9]);
    jpdown.add(jbmutil);
    jpdown.add(jbdot);
    jpdown.add(jb[0]); 
    jpdown.add(jbequal);
    jpdown.add(jbdiv);    
    
    Container ca = jf.getContentPane();                                               
    ca.add(jptop,  BorderLayout.NORTH); 
    ca.add(jpdown, BorderLayout.CENTER); 
   
    jf.show();
		
	}    	
    
    //定义事件处理类
    private class ExpressionButtonHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            JButton jbut = (JButton)e.getSource();
            String exp = jexpression.getText();
            exp = exp + jbut.getText();
            jexpression.setText(exp);
        }
    }	
					
    //定义事件处理类
    private class CRButtonHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            jexpression.setText("");
        }
    }	
    
    /*
    public class EnterOutHandle implements MouseListener
    {
    	public void mousePressed(MouseEvent e){
    	}
    	
    	public void mouseReleased(MouseEvent e){
    	}
    	
    	public void mouseEntered(MouseEvent e){
    		JButton jbsource = (JButton)e.getSource();
    		jbsource.setFont(newfnt);
    	}

    	public void mouseExited(MouseEvent e){
    		JButton jbsource = (JButton)e.getSource();
    		jbsource.setFont(oldfnt);    		
    		
    	} 
    	
    	public void mouseClicked(MouseEvent e){
    	}      	   	    	    	
    }
    */
    
     public class EnterOutHandle extends MouseAdapter
    {

    	
    	public void mouseEntered(MouseEvent e){
    		JButton jbsource = (JButton)e.getSource();
    		jbsource.setFont(newfnt);
    	}

    	public void mouseExited(MouseEvent e){
    		JButton jbsource = (JButton)e.getSource();
    		jbsource.setFont(oldfnt);    		
    		
    	} 
   	   	    	    	
    }
       
    
    //定义事件处理类
    private class ResultButtonHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            String exp = jexpression.getText();
            //利用expression类来计算结果
            expression expr = new expression(exp);
            double re = 0;
            try{
            	re = expr.getResult();
            }catch(IllegalExpressionException le)
            {
            	  JOptionPane.showMessageDialog(jf, le.toString());
            }
            
            jexpression.setText(re + "");
        }
    }	    
	
	public static void main(String[] args)
  {
	  computor jf = new computor();
	
  }
}