JAVA | 學生選課系統

這裏使用JAVA語言編寫的簡易的學生選課系統，展示的都是這個系統核心代碼。

其中有不足歡迎批評和指正！

 

連接數據庫的代碼

package connection;
//鏈接數據庫student

import java.sql.Connection;
import java.sql.DriverManager;
//import java.sql.Statement;
import java.sql.SQLException;

public class xu{

private static Connection conn = null;
static {
try {
// 註冊驅動
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
// 得到一個數據庫鏈接
conn = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=student","sa","123456");
}catch(ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public static Connection getConnection() {
return conn;
}
}

 

 

選課的操做代碼

package connection;

import java.sql.*;
import java.util.*;

public class test1{

private static String ID; // 此處的ID設爲全局變量，在下面某些方法裏會用到
private static Scanner console = new Scanner(System.in);
private static String managerPass = "123456";
private static Connection conn = xu.getConnection();


public static void main(String [] args) throws SQLException {

System.out.println("Welcome to the student selection system!\n\n"
+"if you are maneger please choose 六、七、八、九、10\n"
+"if you are student Please choose 一、二、三、四、五、10\n");
ShowMenu();
}

public static void ShowMenu() throws SQLException {

System.out.println("-----------option-------------\n");

System.out.println("1--Student login"); // 學生登陸
System.out.println("2--Change password"); // 學生修改密碼
System.out.println("3--Choose course"); // 學生選課
System.out.println("4--Get course list"); // 學生查看本身的課程表
System.out.println("5--Student rigistration"); // 學生註冊帳號
System.out.println("6--Create student"); // 管理員建立學生
System.out.println("7--Create course"); // 管理員建立課表
System.out.println("8--Get student list"); // 管理員查看學生表
System.out.println("9--Get course list1"); // 管理員查看選課表裏的課程
System.out.println("10--exit\n"); // 退出

Test();
}



public static void Test() throws SQLException {

System.out.println("manager choose 1 ,student choose 0");
int choose1 = console.nextInt(); //int 用nextInt()

if(choose1 == 1) {

System.out.println("Please input your password :");
String password = console.next(); //String 用next()

if(password.equals(managerPass)) {

System.out.println("Welcome manager!\n");
ManagerMenu1();
}

else {

System.out.println("Your password is worry!"); }
}

else if(choose1 == 0) {

System.out.println("Welcome Student!");
StudentMenu1();
}
}



/*管理員操做菜單*/
public static void ManagerMenu1() throws SQLException {

System.out.println("----------Manager----------\n");
System.out.println("Please choose option");
int choose2 = console.nextInt();

switch(choose2) {

case 1 :
case 2 :
case 3 :
case 4 :
case 5 :
System.out.println("This is student`s option,try again!");
ManagerMenu1();
break;
case 6 : CreateStu();break;
case 7 : CreateCourse();break;
case 8 : GetStudentList();break;
case 9 : GetCourseList1();break;
case 10 : System.exit(0);break;
default : System.out.println("Please input an right number , try again!"); ManagerMenu1();

}
}



/*學生操做菜單*/
public static void StudentMenu1() throws SQLException {

System.out.println("----------Student----------\n");
System.out.println("Please input option");
int choose3 = console.nextInt();

switch(choose3) {

case 1 : StuLogin();break;
case 2 : ChangePass();break;

//在進行Choose course,Get course list以前都要求學生進行StuLogin操做

case 3 :
case 4 : System.out.println("you must login before you can do it!\n");StuLogin();break;
case 5 : StuRigistration();break;
case 6 :
case 7 :
case 8 :
case 9 : System.out.println("This is manager`s option,try again!");StudentMenu1();break;
case 10 : System.exit(0);break;
default : System.out.println("Please input an right number,try again!");StudentMenu1();

}
}

/*管理員建立課程*/
public static void CreateCourse() throws SQLException{

try {
/* 經過connection數據庫連接對象 建立一個statement對象數據庫操做對象,stat對象再獲取一個執行sql的語句。
* stat對象就是java程序與Database的一個鏈接通道*/

Statement stat = conn.createStatement();
String sql1 = "insert into course(couID,couName,couTeacher)values(1,'軟件工程','黃偉國')";
String sql2 = "insert into course(couID,couName,couTeacher)values(2,'數據庫','韋美雁')";
String sql3 = "insert into course(couID,couName,couTeacher)values(3,'算法設計','黎明')";
String sql4 = "insert into course(couID,couName,couTeacher)values(4,'大學英語','章琴')";
String sql5 = "insert into course(couID,couName,couTeacher)values(5,'Java','唐雅媛')";

int a = stat.executeUpdate(sql1);
int b = stat.executeUpdate(sql2);
int c = stat.executeUpdate(sql3);
int d = stat.executeUpdate(sql4);
int e = stat.executeUpdate(sql5);

int sum = a + b + c + d + e;
System.out.println("成功添加"+ sum + "行課程數據");
ManagerMenu1();

} catch (SQLException e) {
// TODO Auto-generated catch block
// e.printStackTrace();
System.out.println("Course already exists");

ManagerMenu1();
}
}



/*管理員建立學生*/
public static void CreateStu() throws SQLException {


try {
Statement stat = conn.createStatement();
String sql1 = "insert into student(stuID,stuName) Values(20160501,'徐明正')";

// 這裏對學生信息的輸入也必須一個一個輸入，這是系統的缺陷，問題待解決

int a = stat.executeUpdate(sql1);
System.out.println("成功添加"+ a + "行學生數據");
ManagerMenu1();

}catch(SQLException e) {
// TODO Auto-generated catch block
System.out.println("The student already exists");

ManagerMenu1();
}
}


/*學生登陸*/
public static void StuLogin() throws SQLException {

System.out.println("Please input your stuID"); // 輸入帳號
ID = console.next();

System.out.println("Please input your Password"); // 輸入密碼
String stuPassword = console.next();

String stuID = null;
String Password = null;

Statement stat ;
ResultSet rs ;

try {
stat = conn.createStatement();
String sql1 = "select * from login "; /* 從login表中查詢其全部屬性值，則stuID 和 Password都有了。
rs是結果集。查詢出的記錄是一個列表，初始時指針指向的是第一條記錄以前的。*/
boolean flag;
rs = stat.executeQuery(sql1);

while(flag = rs.next()) { // rs.next(); //返回值爲true or false

stuID = rs.getString("stuID");
Password = rs.getString("Password");

if( ID.equals(stuID) && stuPassword.equals(Password)) // 注意這裏，跳出循環的條件很重要

break;

// 若是在數據庫裏沒有找到與用戶輸入的stuID和Password相匹配的stuID和Password,flag則變爲false

}

if(!flag){ // 當flag 爲 false 時

System.out.println("The ID or Password is worry!Please input your ID and Password again\n");
StuLogin();
}

else {
System.out.println("***"+ID+"***"+stuID +"***"+stuPassword+"***"+Password+"***");

System.out.println("Login Successful!\n");
System.out.println("------------------Please choose option------------------\n"
// +"If you want to Change Password ,Please choose 2\n"
+"If you want to Choose Course,Please choose 3\n"+"If you want to Get Course List,Please choose 4\n"
+"If you want to exit ,Please choose 8\n");

int choose4 = console.nextInt();

switch(choose4) {

// case 2 : ChangePass();break;
case 3 : ChooseCourse();break;
case 4 : GetCourseList();break;
case 10 : System.exit(0);break;
default : System.out.println("You input an invalid number!");

}

}

} catch (SQLException e) {

// TODO Auto-generated catch block
e.printStackTrace();
}

}

/*在這裏說明一下 方法execute 、executeQuery、executeUpdate三者的區別
* 方法executeQuery 用於單個結果集的語句，如select。他會把查詢的結果放入ResultSet類對象中供使用。
* 方法executeUpdate 用於執行insert、update或delete語句<返回值爲整數>以及SQL DDL（數據定義語言），如create table 和 drop table <返回值爲零>。
* 方法execute 用於執行返回多個結果集、多個更新計數或兩者組合的語句。*/



/*學生修改密碼*/
public static void ChangePass() throws SQLException {

// System.out.println(ID);

/*此處的ID應該必需要從新輸入，不然當選擇對數據庫中某個ID更新的Password進行修改時，沒有對應的ID*/

System.out.println("Please input your ID");
String ID = console.next();
System.out.println("Please input your new Password");
String NewPassword = console.next();

Statement stat ;

try {

stat = conn.createStatement(); // 兩種寫法均可以
// stat = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String sql ="UPDATE login SET Password =" + "" + NewPassword + " where stuID ="+ ID;

//注意，此處的NewPassword 和 ID 沒有要用''括起來

// String sql1 ="UPDATE login SET Password = 111 where stuID = 20156022";

int a = stat.executeUpdate(sql);
System.out.println(a);

if(a != 0) {

System.out.println("成功修改"+a+"行記錄");
System.out.println("Your new Password is "+ NewPassword);

StudentMenu1();
}

else System.out.println("\n"+"Changing the Password is failed!");

}catch(SQLException e) {

// TODO Auto-generated catch block
e.printStackTrace();
}

}



/*學生選課*/
public static void ChooseCourse() throws SQLException {

System.out.println(ID);
String couID = null;
String couName = null;
String couTeacher = null;

Statement stat;
ResultSet rs;

try {

stat = conn.createStatement();
String sql = "select * from course";
rs = stat.executeQuery(sql);

System.out.println("--------可選課程的信息-------");
while(rs.next()) {

couID = rs.getString("couID");
couName = rs.getString("couName");
couTeacher = rs.getString("couTeacher");

System.out.println(couID + " " + couName + " " + couTeacher);
}

System.out.println("\n Please choose your course \n");

stat= conn.createStatement();

// 此處stuID固定位學生登陸時所用的ID,這樣能夠保證登陸本身的帳號卻能選別的帳號的課程

System.out.println("input CourseID");
int ID1 = console.nextInt();
int ID2 = console.nextInt();
int ID3 = console.nextInt();

// 這樣寫 ，學生選課的數目必須固定爲3門，問題待解決

String sql1 = "insert into stuCourse(stuID,couID1,couID2,couID3)VALUES(" + ID + ","+ ID1 + "," + ID2 + "," +ID3 +")";
int i = stat.executeUpdate(sql1);

if(i != 0) {
System.out.println("成功選入課程");

GetCourseList();
}
else System.out.println("選課錯誤");

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}



/*學生獲取已選課程列表*/
public static void GetCourseList() throws SQLException {

System.out.println("\nHere is your course that you have choose\n");

Statement stat = null;
ResultSet rs = null;

try {

stat = conn.createStatement();
String sql = "select * from stuCourse ";
rs = stat.executeQuery(sql);

String stuID = null;
String couID1 = null;
String couID2 = null;
String couID3 = null;
String couID4 = null;

while(rs.next()) {

stuID = rs.getString("stuID");
couID1 = rs.getString("couID1");
couID2 = rs.getString("couID2");
couID3 = rs.getString("couID3");
couID4 = rs.getString("couID4");


if(stuID.equals(ID))

System.out.println(stuID + " " + couID1 + " " + couID2 + " " + couID3 + " " + couID4 + "\n");

}

}catch(SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}



/*學生註冊*/
public static void StuRigistration() throws SQLException{

System.out.println("Please input your ID ");
String ID = console.next();
System.out.println("Please input your Password");
String Password = console.next();

try {
Statement stat = conn.createStatement();
String sql1 = "insert into login(stuID,Password)Values(" + ID + ", " + Password + ")";
//這裏密碼只能輸入數字,問題待解決

int a = stat .executeUpdate(sql1);
System.out.println("成功註冊"+ a +"個帳號");

StudentMenu1();

}catch(SQLException e) {
// TODO Auto-generated catch block
System.out.println("ID already exists");
}
}


/* 管理員查看學生表 */
public static void GetStudentList() {

System.out.println("\n Here is student` information \n");

Statement stat = null;
ResultSet rs = null;

try {

stat = conn.createStatement();
String sql = "select * from student ";
rs = stat.executeQuery(sql);

String stuID = null;
String stuName = null;

while(rs.next()) { stuID = rs.getString("stuID"); stuName= rs.getString("stuName"); System.out.println(stuID + " " + stuName + "\n"); ManagerMenu1(); } }catch(SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /* 管理員查看選課表裏的課程*/ public static void GetCourseList1() { System.out.println("\n Here is course`information \n"); Statement stat = null; ResultSet rs = null; try { stat = conn.createStatement(); String sql = "select * from course "; rs = stat.executeQuery(sql); String couID = null; String couName = null; String couTeacher = null; while(rs.next()) { couID = rs.getString("couID"); couName = rs.getString("couName"); couTeacher = rs.getString("couTeacher"); System.out.println(couID + " " + couName + " " + couTeacher + "\n"); ManagerMenu1(); } }catch(SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }