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服务器之家。

原文链接：https://blog.csdn.net/wrxingkong/article/details/81486148