littleprogramapplet.java

运行在JDK下的学生成绩管理系统源码.可以查询数据

                }else 
                    throw new NumberNotFoundException();
           Collection c = mp.values();
            Iterator iter = c.iterator();
            while(iter.hasNext())
            {
                s1 = (String)iter.next();
                s3 +=s1+"\n";
            }
            BufferedReader in2 =
                new BufferedReader(
                        new StringReader(s3));
            PrintWriter out =
                new PrintWriter(
                        new BufferedWriter(
                                new FileWriter("data.txt")));
            //System.out.println("delete No"+deleteNumber);
            while( (s1 = in2.readLine())!=null)
            {
                out.println(s1);
            }
            out.close();
            }catch (NumberNotFoundException e)
            {
                isDelete = false;
                System.out.println(deleteNumber+" no found :(");    
            }
        }catch(IOException e){}
    }
    public long numberTokenizer(String s)
    throws IOException
    {
        StringTokenizer st = 
            new StringTokenizer(s," ");
        return Integer.valueOf((st.nextToken())).longValue();
    }
    public void findData(long find)//查找数据 
    throws IOException,NumberNotFoundException
    {
        isFind = true;
        String s = "",findString ="";
        long i;
        DataMap dm = new DataMap();
        BufferedReader in =
            new BufferedReader(
                    new FileReader("data.txt"));
        while ((s=in.readLine())!=null)
        {
            i=numberTokenizer(s);
            dm.put(i,s);
        }
        //in.close();
        try{
            if(dm.containsKey( String.valueOf(find).toString()))
            {
                findString = dm.get(find);
                System.out.println("学号"+find+"学生的资料是:");
                System.out.println(findString);
            }else 
                throw  new NumberNotFoundException();
        }catch (NumberNotFoundException e){
            System.out.println(find+" no found :(");
            isFind = false;
        }        
    }
    public static void print()//读取文本文件把数据打印到终端的方法
    throws IOException
    {
        try{
            BufferedReader in =
                new BufferedReader(
                        new FileReader("data.txt"));
            String read = "";
            while ((read = in.readLine())!=null)
                System.out.println(read);
        }catch(IOException e){}
    }
    public static void timeOut(double sec)//停顿短暂时间的一个方法完全可以不要这个功能
    {
        double seconds = sec;
        long t = System.currentTimeMillis()+(int)(seconds*1000);
        while ((System.currentTimeMillis())<t)
            ;
    }
    public void numSort()//按学号排序
    throws IOException
    {
        long i = 0;
        String s = "";
        try{
            DataArrayList dal = new DataArrayList();
            BufferedReader in =
                new BufferedReader(
                        new FileReader("data.txt"));
            while ((s=in.readLine())!=null)
            {
                i=numberTokenizer(s);
                dal.add(i);
            }
            Collections.sort(dal);
            DataMap dm = new DataMap();
            BufferedReader in2 =
                new BufferedReader(
                        new FileReader("data.txt"));
            while ((s=in2.readLine())!=null)
            {
                i=numberTokenizer(s);
                dm.put(i,s);
            }
            PrintWriter out =
                new PrintWriter (
                        new BufferedWriter(
                                new FileWriter("data.txt")));
            Iterator it = dal.iterator();
            long temp = 0;
            String tempStr = "";
            while (it.hasNext())
            {
                temp = Integer.valueOf((String)it.next()).longValue();
                tempStr = dm.get(temp);
                out.println(tempStr);
            }
            out.close();
        }catch(IOException e){}
    }
    public void rewrite()
    throws IOException,NumberNotFoundException
    {
        try{
            System.out.print("请输入你要修改的学生学号:");
            BufferedReader in =
                new BufferedReader (
                        new InputStreamReader(System.in));
            String inputLine = in.readLine();
            long num = Integer.valueOf(inputLine).longValue();
            findData(num);
            if(isFind)
            {
            deleteData(num);
            System.out.print("请重新输入该学生的资料:");
            String str = inputData();
            addData(str);
            System.out.println("rewrite true!");
            }            
        }catch(IOException e){}
        catch(NumberNotFoundException e){}
    }
    public int count()
    throws IOException 
    {
        
        DataArrayList dal = new DataArrayList();
        try{
            String s = "";
            long i =0;
            BufferedReader in =
                new BufferedReader(
                        new FileReader("data.txt"));
            while ((s=in.readLine())!=null)
            {
                i=numberTokenizer(s);
                dal.add(i);
            }
        }catch(IOException e){}
        return dal.size();
    }
}
/*
 * 
 * @author RangWei
 * TODO 这是个我们写的一个容器,继承公共类HashMap
 * 大概的功能就相当一个数组
 * 
 */
class DataMap extends HashMap//一个存储数据的Map                  
{
    public void put(long i,String str)//把学号和数据放进这个Map
    {                                 //以后一个学号(key)对应的是一个人的数据(value)
        put(String.valueOf(i).toString(),str);
    }
    public void remove(long i)//接收学号,然后删除学号(key)和它对应的数据(value)
    {
        remove(String.valueOf(i).toString().toString());
    }
    public String get(long i)//接收一个学号,然后返回这个key对应的value
    {
        String s = String.valueOf(i).toString();
        if (!containsKey(s))
        {
            System.err.println("Not found Key: "+s);
        }
        return (String)get(s);
    }
}
/*
 * 
 * @author RangWei
 *
 * TODO 这个类继承ArrayList
 * 用来按数字排序,在用学号排序时要用到它
 * 
 */
class DataArrayList extends ArrayList
{
    public void add(long num)
    {
        String numToString = String.valueOf(num).toString();
        add(numToString);
    }
}
/*
 * 
 * @author RangWei
 *
 * TODO 增加的一个Exception,主要是在文件里没有要找
 * 的学号就抛出
 * 
 */
class NumberNotFoundException extends Exception
{                                                           
    public NumberNotFoundException()
    {}
}