xsxx.java

自己写的java学生信息管理系统

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 xsxx {
	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{ 
xsxx lp = new xsxx(); 
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()).longV

alue();// 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())) {
				fin

				dString = 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() {
	}
}