Java學生成績管理系統源代碼： 
imporjava.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 讓煒 
* @since 1.0 
* 
* TODO 學生成績管理系統 
* 通過學號查找,修改,刪除數據 
* 
*/ 
public class LittleProgram 
{ 
static boolean isDelete = true; 
static boolean isFind = true; 
public static void main(String [] args)//主方法,程序從這里開始運行 
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學生成績管理系統1.1"); 
System.out.println("\t\t請用學號查找,修改,刪除數據"); 
System.out.println(); 
System.out.println("\t####################################\n"); 
System.out.print("1.增加數據:\n"+ 
"2.查找數據:\n"+ 
"3.刪除數據:\n"+ 
"4.清除所有數據:\n"+ 
"5.把數據全部打印到屏幕\n"+ 
"6.把成績按學號排序\n"+ 
"7.修改數據\n"+ 
"8.統計已記錄成績學生數\n"+ 
"9.關于作者\n"+ 
"0.退出程序.\n" + 
"輸入:"); 
BufferedReader in = //從終 
new BufferedReader( //端接 
new InputStreamReader(System.in));//收數 
String inputLine = in.readLine(); //字選 
choice= Integer.valueOf(inputLine).intValue();//項; 
switch(choice) 
{ 
case 1: {//1.增加數據 
String str = lp.inputData(); 
lp.addData(str); 
System.out.println("增加數據成功."); 
timeOut(1); 
}break; 
case 2: {//2.查找數據 
long find = 0; 
System.out.print("請輸入你要查找的學生學號:"); 
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.刪除數據 
long deleteNumber = 0; 
System.out.print("請輸入你想刪除的同學的學號:"); 
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("刪除數據成功!"); 
timeOut(1); 
}break; 
case 4: { 
lp.clearData();//4.清除所有數據 
timeOut(1); 
}break; 
case 5: { 
print();//5.把數據全部打印到屏幕 
timeOut(2); 
}break; 
case 6: { 
lp.numSort();//6.把成績按學號排序 
System.out.println("按照學號從小到大排序成功!\n"+ 
"排序后:\n"); 
print(); 
timeOut(2); 
}break; 
case 7: { 
lp.rewrite();//7.修改數據 
timeOut(2); 
}break; 
case 8: { 
int count = lp.count(); 
System.out.println("共有"+count+"個學生已經記錄."); 
timeOut(2); 
}break; 
case 9: { 
System.out.print("\t\t讓煒\n"+ 
"\t\t上海電力學院通信工程系\n"+ 
"\t\tQQ:254482170\n"); 
timeOut(4); 
}break; 
}while (choice != 0); 
System.out.println("Bye! ^-^"); 
System.exit(0); 
} 
public String inputData()//從終端接收數據的方法,返回字符串 
throws IOException,NumberFormatException 
{ 
System.out.print("請依次輸入 :學號 姓名 性別 成績\n" + 
"每項數據請用空格隔開:"); 
String all = ""; 
try{ 
BufferedReader in = //從終 
new BufferedReader ( //端接 
new InputStreamReader(System.in)); //收數 
String inputLine = in.readLine(); //據 
StringTokenizer str = 
new StringTokenizer(inputLine," ");//接收的數據用空格隔開,這個類用來提取每個字符串 
long num = Integer.valueOf(str.nextToken()).longValue();//學號 
String name = (String)str.nextToken(); //姓名 
String sex = (String)str.nextToken(); //性別 
double mark = Integer.valueOf(str.nextToken()).doubleValue();//分數 
all = String.valueOf(num) +" , "+ 
name +" , "+ 
sex +" , "+ 
String.valueOf(mark);//把所有的數據用" , "隔開然后在連起來放進字符串all 
}catch (IOException e){} 
catch (NumberFormatException e){} 
return all;//返回字符串all 
} 
public void addData(String str)//增加數據的方法 
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";//把文件中的每行數據全部放進一個字符串s2 
s2+=str+"\n"; //再把s2于形參str相連放進s2 
BufferedReader in2 = //把字符 
new BufferedReader( //串s2也 
new StringReader(s2)); //就是原 
PrintWriter out = //文件+ 
new PrintWriter( //形參str(新輸入的一行數據) 
new BufferedWriter( //重新寫進data.txt 
new FileWriter("data.txt"))); //覆蓋原來的數據 
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的所有數據的方法 
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里寫進一個空字符,所以清除了原來的內容 
out.close(); //關閉文件 
System.out.println("clear data true!"); 
}catch(IOException e){} 
}else{ 
System.err.println("File \"data\" Missing!"); 
} 
} 
public void deleteData(long deleteNumber)//刪除某條數據 
throws IOException,FileNotFoundException 
{ 
isDelete = true; 
try{ 
DataMap mp = new DataMap();//生成一個自己編寫的容器 
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)//查找數據 
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("學號"+find+"學生的資料是:"); 
System.out.println(findString); 
}else 
throw new NumberNotFoundException(); 
}catch (NumberNotFoundException e){ 
System.out.println(find+" no found :("); 
isFind = false; 
} 
} 
public static void print()//讀取文本文件把數據打印到終端的方法 
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)//停頓短暫時間的一個方法完全可以不要這個功能 
{ 
double seconds = sec; 
long t = System.currentTimeMillis()+(int)(seconds*1000); 
while ((System.currentTimeMillis())<t) 
; 
} 
public void numSort()//按學號排序 
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);