marksmanagingsystem.txt

Java写的可以对学生成绩进行管理的一个系统。

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.StringTokenizer;

/*
* Created on 2005-1-11
*/

/**
* @author 让炜
* @since 1.0
*
* TODO 学生成绩管理系统
* 通过学号查找,修改,删除数据
* 
*/
public class LittleProgram 
{
   static boolean isDelete = true;
   static boolean isFind = true;
   public static void main(String [] args)//主方法,程序从这里开始运行  
   throws IOException,NumberNotFoundException
   {
      int choice=-1;
      do{
        LittleProgram lp = new LittleProgram();
        System.out.println();
        System.out.println("\t####################################");
        System.out.println();
        System.out.println("\t\t Java学生成绩管理系统1.1");
        System.out.println("\t\t请用学号查找,修改,删除数据");
        System.out.println();
        System.out.println("\t####################################\n");
        System.out.print("1.增加数据:\n"+
              "2.查找数据:\n"+
              "3.删除数据:\n"+
              "4.清除所有数据:\n"+
              "5.把数据全部打印到屏幕\n"+
              "6.把成绩按学号排序\n"+
              "7.修改数据\n"+
              "8.统计已记录成绩学生数\n"+
              "9.关于作者\n"+
              "0.退出程序.\n" +
              "输入:");
        BufferedReader in =                  //从终
           new BufferedReader(                //端接
                new InputStreamReader(System.in));//收数
        String inputLine = in.readLine();         //字选
        choice= Integer.valueOf(inputLine).intValue();//项;
        switch(choice)
        {
        case 1: {//1.增加数据             
           String str = lp.inputData();
           lp.addData(str);
           System.out.println("增加数据成功.");
           timeOut(1);
        }break;
        case 2: {//2.查找数据
           long find = 0;
           System.out.print("请输入你要查找的学生学号:");
           BufferedReader inn =
              new BufferedReader(
                   new InputStreamReader(System.in));
           String inputLi = inn.readLine();
           find = Integer.valueOf(inputLi).longValue();
           lp.findData(find);
           
           timeOut(2);
        }break;
        case 3: {//3.删除数据
           long deleteNumber = 0;
           System.out.print("请输入你想删除的同学的学号:");
           BufferedReader bf =
              new BufferedReader (
                   new InputStreamReader(System.in));
           String inputL = bf.readLine();
           deleteNumber = Integer.valueOf(inputL).longValue();
           lp.deleteData(deleteNumber);
           if(isDelete)
           System.out.println("删除数据成功!");
           timeOut(1);
        }break;
        case 4: {  
           lp.clearData();//4.清除所有数据
           timeOut(1);
        }break;
        case 5: {
           print();//5.把数据全部打印到屏幕
           timeOut(2);
        }break;
        case 6: {
           lp.numSort();//6.把成绩按学号排序 
           System.out.println("按照学号从小到大排序成功!\n"+
           "排序后:\n");
           print();
           timeOut(2);
        }break;
        case 7: {
           lp.rewrite();//7.修改数据
           timeOut(2);
        }break;
        case 8: {
           int count = lp.count();
           System.out.println("共有"+count+"个学生已经记录.");
           timeOut(2);
        }break;
        case 9: {
           System.out.print("\t\t让炜\n"+
                "\t\t上海电力学院通信工程系\n"+
                "\t\tQQ:254482170\n");
           timeOut(4);
        }break;
      }while (choice != 0);
      System.out.println("Bye! ^-^");
      System.exit(0);
   }
   public String inputData()//从终端接收数据的方法,返回字符串
   throws IOException,NumberFormatException
   {
        System.out.print("请依次输入 :学号 姓名 性别 成绩\n" +
       "每项数据请用空格隔开:");
        String all = "";
      try{
        BufferedReader in =                     //从终
           new BufferedReader (                  //端接
                new InputStreamReader(System.in));   //收数    
           String inputLine = in.readLine();         //据
           StringTokenizer str =                             
              new StringTokenizer(inputLine," ");//接收的数据用空格隔开,这个类用来提取每个字符串                  
           long num = Integer.valueOf(str.nextToken()).longValue();//学号        
           String name = (String)str.nextToken();            //姓名
           String sex = (String)str.nextToken();             //性别 
           double mark = Integer.valueOf(str.nextToken()).doubleValue();//分数 
           all = String.valueOf(num) +" , "+
           name +" , "+
           sex +" , "+
           String.valueOf(mark);//把所有的数据用" , "隔开然后在连起来放进字符串all        
      }catch (IOException e){}
      catch (NumberFormatException e){}
      return all;//返回字符串all
   }
   public void addData(String str)//增加数据的方法
   throws IOException
   {
      String s1 ="",s2="" ,s3= "";
      File file = new File("data.txt");
      if (file.exists())//如果文件data.txt存在
      {
      try{
        BufferedReader in =
           new BufferedReader(
                new FileReader("data.txt"));
        while ((s1=in.readLine())!=null)
           s2+=s1+"\n";//把文件中的每行数据全部放进一个字符串s2                  
        s2+=str+"\n";  //再把s2于形参str相连放进s2
        BufferedReader in2 =                       //把字符
           new BufferedReader(                     //串s2也 
                new StringReader(s2));              //就是原
        PrintWriter out =                         //文件+
           new PrintWriter(                       //形参str(新输入的一行数据)
                new BufferedWriter(                //重新写进data.txt
                      new FileWriter("data.txt")));    //覆盖原来的数据 
        while ((s3=in2.readLine())!= null)
        {
           out.println(s3);
        }
        out.close();
        //System.out.println("write data true.");
      }catch (IOException e){}
      }else{
        System.err.println("File \"data\" Missing!");
      }
   }
   public void clearData()//清除data.txt的所有数据的方法
   throws IOException
   {
      File file = new File("data.txt");
      if(file.exists())//如果文件在 
      {
        try{
           PrintWriter out = 
              new PrintWriter(
                   new BufferedWriter(
                        new FileWriter(file)));
           out.print("");//在文件data.txt里写进一个空字符,所以清除了原来的内容
           out.close();  //关闭文件
           System.out.println("clear data true!");
        }catch(IOException e){}
      }else{
           System.err.println("File \"data\" Missing!");
      }
   }
   public void deleteData(long deleteNumber)//删除某条数据
   throws IOException,FileNotFoundException
   {
      isDelete = true;
      try{
      DataMap mp = new DataMap();//生成一个自己编写的容器
      long j=0;
      String s1="",s2="",s3="";
        BufferedReader in =
           new BufferedReader(
                new FileReader("data.txt"));
        while ((s1=in.readLine())!=null)
        {
           j=numberTokenizer(s1);
           mp.put(j,s1);
        }
        try{
           if(mp.containsKey( String.valueOf(deleteNumber).toString()))
           {
              mp.remove(deleteNumber);
           }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()
   {}
}