cjtj.java

学生成绩统计

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

public class CJTJ extends JFrame implements ActionListener
{
	JLabel jlSubject=new JLabel("考试科目");
	JTextField jtfSubject=new JTextField();
	JLabel jlCount=new JLabel("考试人数");
	JTextField jtfCount=new JTextField();
	JButton jbOk=new JButton("确定");
	JButton jbAccount=new JButton("统计");
	
	JPanel jpList=new JPanel();
	JScrollPane jsp=new JScrollPane(jpList);
	JLabel jlSno=new JLabel("学号");
	JLabel jlSname=new JLabel("姓名");
	JLabel jlScore=new JLabel("成绩");
	
	int total;//总人数
	Student[] sa;
	
	public CJTJ()
	{
		this.setTitle("成绩统计");
		this.setLayout(null);
		
		jlSubject.setBounds(10,10,80,20);
		this.add(jlSubject);
		jtfSubject.setBounds(70,10,90,20);
		this.add(jtfSubject);
		
		jlCount.setBounds(170,10,60,20);
		this.add(jlCount);
		jtfCount.setBounds(230,10,90,20);
		this.add(jtfCount);
		
		jbOk.setBounds(330,10,60,20);
		this.add(jbOk);
		
		jpList.setBackground(Color.red);
		jsp.setBounds(10,40,380,300);
		this.add(jsp);
		
		jbAccount.setBounds(170,350,60,20);
		this.add(jbAccount);
		
		this.initTable();
		
		this.setBounds(100,100,410,450);
		this.setVisible(true);
		this.setStatus(false);
		
		jbOk.addActionListener(this);
		jbAccount.addActionListener(this);
	}
	
	public void initTable()
	{
		jpList.setLayout(null);
		jlSno.setBounds(50,5,80,20);
		jpList.add(jlSno);
		
		jlSname.setBounds(165,5,80,20);
		jpList.add(jlSname);
		
		jlScore.setBounds(290,5,80,20);
		jpList.add(jlScore);
	}
	
	public void setStatus(boolean b)
	{
		this.jtfSubject.setEnabled(!b);
		this.jtfCount.setEnabled(!b);
		this.jbOk.setEnabled(!b);
		this.jbAccount.setEnabled(b);
	}
	
	public void actionPerformed(ActionEvent e)
	{
		if(e.getSource()==jbOk)
		{//按下确定按钮
			String sSubject=this.jtfSubject.getText();
			String sCount=this.jtfCount.getText();
			
			if(sSubject.trim().length()==0
			||sCount.trim().length()==0)
			{
				JOptionPane.showMessageDialog(this,"必须输入科目及人数信息！！！",
				"提示",JOptionPane.INFORMATION_MESSAGE);
				return;
			}
			
			try
			{
				total=Integer.parseInt(sCount);
			}
			catch(NumberFormatException ea)
			{
				JOptionPane.showMessageDialog(this,"考试人数必须为整数!!!",
				"提示",JOptionPane.INFORMATION_MESSAGE);
				return;
			}
			
			if(total<=0)
			{
				JOptionPane.showMessageDialog(this,"考试人数必须为正整数！！！",
				"提示",JOptionPane.INFORMATION_MESSAGE);
				return;
			}
			
			sa=new Student[total];
			jpList.setPreferredSize(new Dimension(375,25*(total+1)));
			for(int i=0;i<total;i++)
			{
				sa[i]=new Student();
				sa[i].jtfSno.setBounds(5,25*(i+1),120,20);
				jpList.add(sa[i].jtfSno);
				sa[i].jtfSname.setBounds(130,25*(i+1),120,20);
				jpList.add(sa[i].jtfSname);
				sa[i].jtfSscore.setBounds(255,25*(i+1),120,20);
				jpList.add(sa[i].jtfSscore);				
			}
			
			for(int i=0;i<total;i++)
			{						
				sa[i].jtfSno.addActionListener(new MyAdapter(sa[i].jtfSname));
				sa[i].jtfSname.addActionListener(new MyAdapter(sa[i].jtfSscore));
				
				if(i<total-1)
				{
					sa[i].jtfSscore.addActionListener(new MyAdapter(sa[i+1].jtfSno));
				}
			}
			this.setVisible(false);
			this.setVisible(true);
			this.setStatus(true);
		}
		else if(e.getSource()==jbAccount)
		{//按下统计按钮
			boolean flag=false;
			for(Student ts:sa)
			{
				flag=checkInput(ts.jtfSno,"请输入对应学生的学号！");
				if(flag)
				{
					flag=checkInput(ts.jtfSname,"请输入对应学生的姓名！");
					if(flag)
					{
						flag=checkInput(ts.jtfSscore,"请输入对应学生的成绩！");
						if(!flag)
						{
							return;
						}
					}
					else
					{
						return;
					}
				}
				else
				{
					return;
				}
			}
			
			for(Student ts:sa)
			{
				String tscore=ts.jtfSscore.getText().trim();
				try
				{
					ts.score=Double.parseDouble(tscore);
					if(ts.score>100||ts.score<0)
					{
						JOptionPane.showMessageDialog(this,"成绩必须在0~100之间！",
						"提示",JOptionPane.INFORMATION_MESSAGE);
						ts.jtfSscore.requestFocus(true);
						return;
					}
				}
				catch(NumberFormatException es)
				{
					JOptionPane.showMessageDialog(this,"成绩必须为数值！",
					"提示",JOptionPane.INFORMATION_MESSAGE);
					ts.jtfSscore.requestFocus(true);
					return;
				}
			}
			
			double max=0;
			double min=100.0;
			double avg=0;
			
			for(Student ts:sa)
			{
				if(max<ts.score)
				{
					max=ts.score;
				}
				if(min>ts.score)
				{
					min=ts.score;
				}
				avg+=ts.score;
			}
			avg=avg/total;
			
			String msgr="最高分："+max+"\n"+
						"最低分："+min+"\n"+
						"平均分："+((int)(avg*100))/100.0;
		    JOptionPane.showMessageDialog(this,msgr,"成绩统计结果",
		    JOptionPane.INFORMATION_MESSAGE);
			
		}
	}
	
	public boolean checkInput(JTextField jtf,String msg)
	{
		if(jtf.getText().trim().length()==0)
		{
			JOptionPane.showMessageDialog(this,msg,
			"提示",JOptionPane.INFORMATION_MESSAGE);
			jtf.requestFocus(true);
			return false;
		}
		return true;		
	}
	
	public static void main(String args[])
	{
		new CJTJ();
	}
}

class Student
{
	double score;
	JTextField jtfSno=new JTextField();
	JTextField jtfSname=new JTextField();
	JTextField jtfSscore=new JTextField();
}

class MyAdapter implements ActionListener
{
	JTextField jtfNext;
	
	public MyAdapter(JTextField jtfNext)
	{
		this.jtfNext=jtfNext;
	}
	
	public void actionPerformed(ActionEvent e)
	{
		jtfNext.requestFocus(true);
	}
}