本文實例為大家分享了java實現選課系統的具體代碼，供大家參考，具體內容如下
這個程序主要是練習io(文件讀寫，序列化），集合框架的使用
學生端可以實現，查找課程，增加選課，刪除選課的功能
管理端可以實現對備選課程，學生信息的增刪查改
缺點：登陸操作沒有實現密碼驗證和多態。
另外map對象明明put了，可是get的時候竟然會取到null，而且嘗試多次，有時候成功，有時候取到null，并不確定。據說這是由多線程引起的map取值為null，因為多線程部分還沒開始學習，所以也沒做修改。
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//課程信息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 "課程號：" + id + " " + "課程名：" + name; } } |
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//學生信息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 "學號："+id+" " +"姓名："+name; } //遍歷輸出所選課程 public void travese() { if(courses.size()>0) { for (course course : courses) { system.out.println(course); } } else { system.out.println("還沒有選課"); } } public int compareto(student s) { int result=this.id-s.id; return result; } } |
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//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，用來管理學生信息和備選課程 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() { } //~~~~~~~~~~~~~~~~~從文件讀入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(); } } //將信息寫回文件 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 自動生成的 catch 塊 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 自動生成的 catch 塊 e.printstacktrace(); } } //~~~~~~~~~~~~~~~~~~~~~~~~~ 根據list來創建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)); } } // ~~~~~~~~~~~~~~~~~~~~~~ 增刪查改~~~~~~~~~~~~~~~~~~~~~~~ // 增加學生基本信息 public void add() { system.out.println("輸入學生信息，輸入0結束"); 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; } } } // 刪除學生信息 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; } } } // 增加課程基本信息 public void add2() { system.out.println("輸入課程信息，輸入end結束"); 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("添加結束"); break; } } } // 刪除課程信息 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; } } } // 根據學號查找學生 public void query1() { system.out.println("請輸入要查詢的學生學號："); if (in.hasnext()) { int id = in.nextint(); system.out.println(map1.get(id)); map1.get(id).travese(); } } // 根據課程號查找課程 public void query2() { system.out.println("請輸入要查詢的課程號："); if (in.hasnext()) { string id = in.nextline(); system.out.println(map2.get(id)); } } // 修改學生基本信息 public void modify1() { system.out.println("請輸入要修改的學生的學號："); int id = in.nextint(); student s = map1.get(id); system.out.println("輸入修改后的學生信息："); 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"); } // 修改課程信息 public void modify2() { system.out.println("請輸入要修改的課程的課程號："); string id = in.nextline(); course cr = map2.get(id); system.out.println("輸入修改后的課程信息："); 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"); } // ~~~~~~~~~~~~~~~~~~~~~~ 遍歷list~~~~~~~~~~~~~~~~~~~~~~~ void display1() { system.out.println("所有的學生信息："); for (student s : students) { system.out.println(s.tostring()); s.travese(); } } void display2() { system.out.println("所有的備選課程信息："); for (course course : courses) { system.out.println(course.tostring()); } }public void close(){ in.close();}} |
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//學生操作端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(); } // ~~~~~~~~~~~~~~~~~從文件讀入信息~~~~~~~~~~~~~~~~~~~~~ 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(); } } // 將信息寫回文件 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 自動生成的 catch 塊 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 自動生成的 catch 塊 e.printstacktrace(); } } //~~~~~~~~~~~~~~~~~~~~~~~~~ 根據list來創建map~~~~~~~~~~~~~~~~~~~~~~~ public void createmap() { for (int i = 0; i < courses.size(); i++) { map.put(courses.get(i).getid(), courses.get(i)); } //遍歷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)); } */ } //遍歷顯示備選課程 public void displayallcourse() { system.out.println("所有的備選課程信息："); for (course course : courses) { system.out.println(course.tostring()); } } //根據課程號查詢備選課程 public void querycourse() { system.out.println("請輸入要查詢的課程號："); string str = in.next(); system.out.println(str); system.out.println((map.containskey(str) ? "yes" : "no")); system.out.println(map.get(str)); } //顯示所選課程 public void display() { system.out.println("所選課程："); st.travese(); } //增加所選課程 public void addselect() { system.out.println("輸入所選課程的課程號，輸入end結束"); while (true) { string id = in.nextline(); if (!id.equals("end")) { course cr = map.get(id); st.getcourses().add(cr); system.out.println("選課成功"); } else { // system.out.println("添加結束"); break; } } } //減少所選課程 public void deleteselect() { system.out.println("要刪除課程的課程號，輸入end結束"); while (true) { string id = in.nextline(); if (!id.equals("end")) { course cr = map.get(id); st.getcourses().remove(cr); system.out.println("刪除成功"); } else { // system.out.println("添加結束"); break; } } } public void close() { in.close(); }} |
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//測試類package selectcourse; import java.util.scanner; public class test { public static void main(string[] args) {//~~~~~~~~~~~~~測試管理端~~~~~~~~~~~~~~~~~~~~~~~~~~ /*添加學生 administratorop a1=new administratorop(); a1.add(); //a1.display1(); // a1.close(); a1.save1();*/ /*添加課程 administratorop a2=new administratorop(); a2.add2(); //a2.display2(); a2.close(); a2.save2();*//* // 測試刪除，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();*///~~~~~~~~~~~~~~~~測試學生端~~~~~~~~~~~~~~~~~~~~~~~~~ /*scanner in=new scanner(system.in); system.out.println("請輸入學號："); 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內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：https://blog.csdn.net/wrxingkong/article/details/81486148
