java实现选课系统

本文实例为大家分享了java实现选课系统的具体代码，供大家参考，具体内容如下

这个程序主要是练习IO(文件读写，序列化），集合框架的使用

学生端可以实现，查找课程，增加选课，删除选课的功能

管理端可以实现对备选课程，学生信息的增删查改

缺点：登陆操作没有实现密码验证和多态。

另外map对象明明put了，可是get的时候竟然会取到null，而且尝试多次，有时候成功，有时候取到null，并不确定。据说这是由多线程引起的map取值为null，因为多线程部分还没开始学习，所以也没做修改。

//课程信息
package selectCourse;

import java.io.Serializable;

public class Course implements Serializable{
 private String id;
 private String name;

 public Course(String id, String name) {
 super();
 this.id = id;
 this.name = name;
 }

 public Course() {
 super();
 }

 public String getId() {
 return id;
 }

 public void setId(String id) {
 this.id = id;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public int hashCode() {
 final int prime = 31;
 int result = 1;
 result = prime * result + ((id == null) ? 0 : id.hashCode());
 result = prime * result + ((name == null) ? 0 : name.hashCode());
 return result;
 }
 public boolean equals(Object obj) {
 if (this == obj)
  return true;
 if (obj == null)
  return false;
 if (getClass() != obj.getClass())
  return false;
 Course other = (Course) obj;
 if (id == null) {
  if (other.id != null)
  return false;
 } else if (!id.equals(other.id))
  return false;
 if (name == null) {
  if (other.name != null)
  return false;
 } else if (!name.equals(other.name))
  return false;
 return true;
 }

 public String toString() {
 return "课程号：" + id + " " + "课程名：" + name;
 }

}

//学生信息
package selectCourse;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

public class Student implements Serializable,Comparable<Student>{

 private int id;
 private String name;
 private Set<Course> courses;

 public Student(int id, String name) {
 super();
 this.id = id;
 this.name = name;
 this.courses = new HashSet<Course>();
 }

 public Student() {
 super();
 this.id = 0;
 this.name = null;
 this.courses = new HashSet<Course>();
 }

 public int getId() {
 return id;
 }

 public void setId(int id) {
 this.id = id;
 }

 public String getName() {
 return name;
 }

 public void setName(String name) {
 this.name = name;
 }

 public Set<Course> getCourses() {
 return courses;
 }

 public void setCourses(Set<Course> courses) {
 this.courses = courses;
 }

 public int hashCode() {
 final int prime = 31;
 int result = 1;
 result = prime * result + id;
 return result;
 }

 public boolean equals(Object obj) {
 if (this == obj)
  return true;
 if (obj == null)
  return false;
 if (getClass() != obj.getClass())
  return false;
 Student other = (Student) obj;
 if (id != other.id)
  return false;
 return true;
 }

 public String toString() {
 return "学号："+id+" " +"姓名："+name;
 }
 //遍历输出所选课程
 public void travese()
 {
 if(courses.size()>0)
 {
 for (Course course : courses) {
  System.out.println(course);
 }
 }
 else
 {
  System.out.println("还没有选课");
 }
 }

 public int compareTo(Student s) {

  int result=this.id-s.id;
  return result;
 }

}

//管理端
package selectCourse;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class AdministratorOp {
//管理端，用来管理学生信息和备选课程
 List<Student> students = new ArrayList<Student>();
 Map<Integer, Student> map1 = new HashMap<Integer, Student>();
 List<Course> courses = new ArrayList<Course>();
 Map<String, Course> map2 = new HashMap<String, Course>();
 Scanner in = new Scanner(System.in);

 public AdministratorOp() {
 }

//~~~~~~~~~~~~~~~~~从文件读入List~~~~~~~~~~~~~~~~~~~~~
 public void load1() {
 File file = new File("students.txt");
 if (!file.exists()) {
  try {
  file.createNewFile();
  } catch (IOException e) {
  e.printStackTrace();
  }
 }
 FileInputStream fis;
 try {
  fis = new FileInputStream(file);
  ObjectInputStream ois = new ObjectInputStream(fis);
  students = (List<Student>) ois.readObject();
  ois.close();
  fis.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  e.printStackTrace();
 } catch (ClassNotFoundException e) {
  e.printStackTrace();
 }

 }

 public void load2() {
 File file = new File("courses.txt");
 if (!file.exists()) {
  try {
  file.createNewFile();
  } catch (IOException e) {
  e.printStackTrace();
  }
 }
 FileInputStream fis;
 try {
  fis = new FileInputStream(file);
  ObjectInputStream ois = new ObjectInputStream(fis);
  courses = (List<Course>) ois.readObject();
  ois.close();
  fis.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  e.printStackTrace();
 } catch (ClassNotFoundException e) {
  e.printStackTrace();
 }

 }

//将信息写回文件
 public void save1() {
 File file = new File("students.txt");
 FileOutputStream fos;
 try {
  fos = new FileOutputStream(file);
  ObjectOutputStream oos = new ObjectOutputStream(fos);
  oos.writeObject(students);
  oos.close();
  fos.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  // TODO 自动生成的 catch 块
  e.printStackTrace();
 }

 }

 public void save2() {
 File file = new File("courses.txt");
 FileOutputStream fos;
 try {
  fos = new FileOutputStream(file);
  ObjectOutputStream oos = new ObjectOutputStream(fos);
  oos.writeObject(courses);
  oos.close();
  fos.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  // TODO 自动生成的 catch 块
  e.printStackTrace();
 }

 }

//~~~~~~~~~~~~~~~~~~~~~~~~~ 根据List来创建Map~~~~~~~~~~~~~~~~~~~~~~~
 public void createMap1() {
 for (int i = 0; i < students.size(); i++) {
  map1.put(students.get(i).getId(), students.get(i));
 }
 }

 public void createMap2() {
 for (int i = 0; i < courses.size(); i++) {
  map2.put(courses.get(i).getId(), courses.get(i));
 }
 }

 // ~~~~~~~~~~~~~~~~~~~~~~ 增删查改~~~~~~~~~~~~~~~~~~~~~~~
 // 增加学生基本信息
 public void add() {
 System.out.println("输入学生信息，输入0结束");
 while (true) {
  int id = in.nextInt();
  if(id!=0) {
  String name = in.next();
  Student s = new Student(id, name);
  students.add(s);
  Collections.sort(students);
  map1.put(id, s);
  System.out.println("添加成功");
  }
  if (id == 0) {
  break;
  }
 }
 }

 // 删除学生信息
 public void del() {
 while(true) {
  int id = in.nextInt();
  Student s = map1.get(id);
  students.remove(s);
  map1.remove(id);
  System.out.println("移除成功");
  if (id == 0) {
  break;
  }
 }
 }
 // 增加课程基本信息
 public void add2() {
 System.out.println("输入课程信息，输入end结束");
 while (true) {
  String id = in.nextLine();
  if(!id.equals("end"))
  {
  String name = in.nextLine();
  Course cr = new Course(id, name);
  courses.add(cr);
  map2.put(id, cr);
  System.out.println("添加成功");
  }
  else{
  //System.out.println("添加结束");
  break;
  }
 }
 }

 // 删除课程信息
 public void del2() {
 while(true) {
  String id = in.next();
  if(!id.equals("end")) {
  Course cr = map2.get(id);
  courses.remove(cr);
  map2.remove(id);
  System.out.println("移除成功");
  }
  else
  {
  break;
  }
 }
 }

 // 根据学号查找学生
 public void query1() {
 System.out.println("请输入要查询的学生学号：");
 if (in.hasNext()) {
  int id = in.nextInt();
  System.out.println(map1.get(id));
  map1.get(id).travese();
 }
 }

 // 根据课程号查找课程
 public void query2() {
 System.out.println("请输入要查询的课程号：");
 if (in.hasNext()) {
  String id = in.nextLine();
  System.out.println(map2.get(id));
 }
 }

 // 修改学生基本信息
 public void modify1() {
 System.out.println("请输入要修改的学生的学号：");
 int id = in.nextInt();
 Student s = map1.get(id);
 System.out.println("输入修改后的学生信息：");
 int no = in.nextInt();
 String name = in.next();
 int i = students.indexOf(s);
 students.set(i, new Student(no, name));
 Collections.sort(students);
 map1.remove(id);
 map1.put(no, new Student(no, name));
 System.out.println("修改成功");
 }

 // 修改课程信息
 public void modify2() {
 System.out.println("请输入要修改的课程的课程号：");
 String id = in.nextLine();
 Course cr = map2.get(id);
 System.out.println("输入修改后的课程信息：");
 String no = in.nextLine();
 String name = in.nextLine();
 int i = courses.indexOf(cr);
 courses.set(i, new Course(no, name));
 map2.remove(id);
 map2.put(no, new Course(no, name));
 System.out.println("修改成功");
 }

// ~~~~~~~~~~~~~~~~~~~~~~ 遍历list~~~~~~~~~~~~~~~~~~~~~~~
 void display1() {
 System.out.println("所有的学生信息：");
 for (Student s : students) {
  System.out.println(s.toString());
  s.travese();
 }
 }

 void display2() {
 System.out.println("所有的备选课程信息：");
 for (Course course : courses) {
  System.out.println(course.toString());
 }
 }
public void close()
{
 in.close();
}
}

//学生操作端
package selectCourse;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class StudentOp {
 Scanner in = new Scanner(System.in);
 Student st;
 List<Student> students = new ArrayList<Student>();
 List<Course> courses = new ArrayList<Course>();
 Map<String, Course> map = new HashMap<String, Course>();

 public StudentOp(int no) {
 load3(no);
 load4();

 }

 // ~~~~~~~~~~~~~~~~~从文件读入信息~~~~~~~~~~~~~~~~~~~~~
 public void load3(int n) {
 File file = new File("students.txt");
 FileInputStream fis;
 try {
  fis = new FileInputStream(file);
  ObjectInputStream ois = new ObjectInputStream(fis);
  students = (List<Student>) ois.readObject();
  ois.close();
  fis.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  e.printStackTrace();
 } catch (ClassNotFoundException e) {
  e.printStackTrace();
 }
 for (int i = 0; i < students.size(); i++) {
  if (n == students.get(i).getId()) {
  st = students.get(i);
  break;
  }
 }

 }

 public void load4() {
 File file = new File("courses.txt");
 if (!file.exists()) {
  try {
  file.createNewFile();
  } catch (IOException e) {
  e.printStackTrace();
  }
 }
 FileInputStream fis;
 try {
  fis = new FileInputStream(file);
  ObjectInputStream ois = new ObjectInputStream(fis);
  courses = (List<Course>) ois.readObject();
  ois.close();
  fis.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  e.printStackTrace();
 } catch (ClassNotFoundException e) {
  e.printStackTrace();
 }

 }

// 将信息写回文件
 public void save3() {
 File file = new File("students.txt");
 FileOutputStream fos;
 try {
  fos = new FileOutputStream(file);
  ObjectOutputStream oos = new ObjectOutputStream(fos);
  oos.writeObject(students);
  oos.close();
  fos.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  // TODO 自动生成的 catch 块
  e.printStackTrace();
 }

 }

 public void save4() {
 File file = new File("courses.txt");
 FileOutputStream fos;
 try {
  fos = new FileOutputStream(file);
  ObjectOutputStream oos = new ObjectOutputStream(fos);
  oos.writeObject(courses);
  oos.close();
  fos.close();
 } catch (FileNotFoundException e) {
  e.printStackTrace();
 } catch (IOException e) {
  // TODO 自动生成的 catch 块
  e.printStackTrace();
 }

 }

//~~~~~~~~~~~~~~~~~~~~~~~~~ 根据List来创建Map~~~~~~~~~~~~~~~~~~~~~~~
 public void createMap() {
 for (int i = 0; i < courses.size(); i++) {
  map.put(courses.get(i).getId(), courses.get(i));
 }

 //遍历map
  /*Set<String> set = map.keySet();
 Iterator<String> iterator = set.iterator();
 while (iterator.hasNext()) {
  String key = iterator.next();
  System.out.println(key + " " + map.get(key));
 } */
 }

//遍历显示备选课程
 public void displayAllCourse() {
 System.out.println("所有的备选课程信息：");
 for (Course course : courses) {
  System.out.println(course.toString());
 }
 }

//根据课程号查询备选课程
 public void queryCourse() {
 System.out.println("请输入要查询的课程号：");
 String str = in.next();
 System.out.println(str);
 System.out.println((map.containsKey(str) ? "yes" : "no"));
 System.out.println(map.get(str));
 }

//显示所选课程
 public void display() {
 System.out.println("所选课程：");
 st.travese();
 }

//增加所选课程
 public void addSelect() {
 System.out.println("输入所选课程的课程号，输入end结束");
 while (true) {
  String id = in.nextLine();
  if (!id.equals("end")) {
  Course cr = map.get(id);
  st.getCourses().add(cr);
  System.out.println("选课成功");
  } else {
  // System.out.println("添加结束");
  break;
  }
 }
 }

//减少所选课程
 public void deleteSelect() {
 System.out.println("要删除课程的课程号，输入end结束");
 while (true) {
  String id = in.nextLine();
  if (!id.equals("end")) {
  Course cr = map.get(id);
  st.getCourses().remove(cr);
  System.out.println("删除成功");
  } else {
  // System.out.println("添加结束");
  break;
  }
 }
 }

 public void close() {
 in.close();
 }
}

//测试类
package selectCourse;

import java.util.Scanner;

public class Test {

 public static void main(String[] args) {
//~~~~~~~~~~~~~测试管理端~~~~~~~~~~~~~~~~~~~~~~~~~~
   /*添加学生
 AdministratorOp a1=new AdministratorOp();
 a1.add();
 //a1.display1();
 // a1.close();
 a1.save1();*/
 /*添加课程
 AdministratorOp a2=new AdministratorOp();
 a2.add2();
 //a2.display2();
 a2.close();
   a2.save2();*/
/* // 测试删除，查找，修改
   AdministratorOp a3=new AdministratorOp();
 a3.load1();
 a3.createMap1();
 a3.load2();
 a3.createMap2();
// a3.display1();
// a3.display2();
// a3.del();
// a3.display1();
// a3.del2();
// a3.display2();
// a3.query1();
// a3.query2();
// a3.modify1();
// a3.display1();
// a3.modify2();
// a3.display2();
    a3.close();
    // a3.save1();
    // a3.save2();*/
//~~~~~~~~~~~~~~~~测试学生端~~~~~~~~~~~~~~~~~~~~~~~~~
  /*Scanner in=new Scanner(System.in);
  System.out.println("请输入学号：");
  int id=in.nextInt();
 StudentOp sto=new StudentOp(id);
 sto.createMap();
 //sto.displayAllCourse();
 //sto.queryCourse();

// sto.addSelect();
// sto.deleteSelect();
 sto.display();
 sto.close();
 in.close();
// sto.save3();
// sto.save4();
*/ }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。