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脚本之家。

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