Java实现选课系统（用集合实现）

实现步骤：

1. 构造课程类Course
2. 构造课程列表类CourseList
3. 构造学生类Student
4. 构造学生--课程映射StudentMap类
5. 主运行程序类Index类

Course.java:

package dk.courses;

/**
 * @author Administrator
 * 课程类
 */
public class Course {
    private String id;
    private String name;

    public Course(String id, String name) {
        super();
        this.id = id;
        this.name = name;
    }
    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 String toString(){
        return "课程编号："+this.getId()+"\t课程名称:"+this.getName();
    }
    /*public boolean equals(Object obj){
        if(this==obj)
            return true;
        if(obj==null)
            return false;
        if(!(obj instanceof Course))
            return false;
        Course c = (Course)obj;
        if(this.name==null){
            if(c.name==null)
                return true;
            else
                return false;
        }else{
            if(this.name.equals(c.name))
                return true;
            else
                return false;
        }
    }*/
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    @Override
    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 (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }

}

CourseList.java:

package dk.courses;
import java.util.List;

import java.util.Iterator;

import java.util.ArrayList;

/**
 * @author Administrator
 * 课程列表类
 */
public class CourseList {
    public static  List<Course> courselist = new ArrayList<Course>();;//课程集合

    public CourseList() {}

    public List<Course> getCourselist() {
        return courselist;
    }

    public void setCourselist(List<Course> courselist) {
        CourseList.courselist = courselist;
    }

    //添加课程
    public static void addCourse(String id, String name){
        Course c = new Course(id, name);
        System.out.println("添加了课程：\t"+"课程编号："+c.getId()+"\t"+"课程名称："+c.getName());
        courselist.add(c);

    }

    //查询课程
    public static Course getCourse(String id){
        Iterator<Course> it = CourseList.courselist.iterator();
        while(it.hasNext()){
            Course c = it.next();
            if(c.getId()==id)
                return c;
        }
        return null;
    }

    //获取课程在集合中的索引
    public static int getCourseIndex(String id){
        int len = CourseList.courselist.size();
        for(int i=0; i<len;i++){
            Course c = CourseList.courselist.get(i);
            if(c.getId()==id)
                return i;
        }
        return -1;
    }

    //获取课程在集合中的索引
    public static int getCourseIndex(Course c){
        return CourseList.courselist.indexOf(c);
    }

    //修改课程
    public static boolean setCourse(String id, String name){
        int index = getCourseIndex(id);
        if(index>=0){
            Course c = CourseList.courselist.get(index);
            c.setName(name);
            CourseList.courselist.set(index, c);
            return true;
        }
        return false;
    }

    //移除课程
    public static boolean removeCourse(String id){
        int index = getCourseIndex(id);
        if(index>=0){
            return CourseList.courselist.remove(index) != null;
        }
        return false;
    }

    //移除所有课程
    public static boolean removeAllCourse(){
        CourseList.courselist.clear();
         return true;
         //return this.courselist.removeAll(courselist);    
    }

    //获取所有课程
    public static void getAllCourse(){
        Iterator<Course> it = CourseList.courselist.iterator();
        show("=========================================================");
        show("课程列表如下：(共有"+CourseList.courselist.size()+"门课程)");
        show("=========================================================");
        while(it.hasNext()){
            Course c = it.next();
            show(c.toString());
        }
        show("=========================================================");
    }

    public static void show(Object obj){
        System.out.println(obj.toString());
    }

    //查找是否存在课程
    public static boolean containCourse(Course c){
        return CourseList.courselist.contains(c);
    }

}

Student.java

package dk.students;

import java.util.ArrayList;

import dk.courses.Course;
import dk.courses.CourseList;

/**
 * @author Administrator
 * 学生类
 */
public class Student implements Comparable<Student>{
    private String id;
    private String name;
    private ArrayList<String> courses;//储存课程编号
    public Student(String id, String name) {
        super();
        this.id = id;
        this.name = name;
        this.courses = new ArrayList<String>();
    }
    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 ArrayList<String> getCourses() {
        return courses;
    }
    public void setCourses(ArrayList<String> courses) {
        this.courses = courses;
    }

    //选择课程
    public boolean selectCourses(String id){
            if(CourseList.getCourseIndex(id)==-1){
                CourseList.show("课程不存在！");
                return false;
            }
            Course c = CourseList.getCourse(id);

            show("您选择了以下课程：");
            show(c.toString());
            return this.courses.add(id);
    }

    //获取课程信息
    public void printCourses(){
        show("=========================================================");
        show(this.toString());
        show("=========================================================");
        show("课表如下:");
        for(String id:this.courses){
            Course c = CourseList.getCourse(id);
            show(c.toString());
        }
        show("=========================================================");
    }

    //删除课程
    public boolean removeCourse(String id){
        int index = this.getIndex(id);
        if(index==-1){
            return false;
        }
        this.courses.remove(index);
        return  true;
    }

    public int getIndex(String id){
        for(int i=0;i<this.courses.size();i++){
            if(this.courses.get(i)==id)
                return i;
        }
        return -1;
    }

    public String toString(){
        return "学号："+this.getId()+"\t姓名："+this.getName()+"\t共选择了门"+this.courses.size()+"课";
    }

    public static void show(Object obj){
        System.out.println(obj.toString());
    }
    @Override
    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;
    }
    @Override
    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 == 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;
    }
    @Override
    public int compareTo(Student o) {
        //return this.name.compareTo(o.name);
        return this.id.compareTo(o.id);
    }

}

StudentMap.java

package dk.map;
import java.util.Map.Entry;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

import dk.students.Student;

public class StudentMap {

    public Map<String, Student> students;
    private Scanner console;
    public StudentMap(){
        this.students = new HashMap<String, Student>();
    }

    //创建键值对
    public void putStudents(){
        console = new Scanner(System.in);
        int i = 0;
        while(i<3){
            System.out.println("请输入学生ID");
            String Id = console.next();
            Student st = this.students.get(Id);
            if(st==null){
                show("请输入学生的姓名");
                String Name = console.next();
                Student student = new Student(Id,Name);
                this.students.put(Id, student);
                show("成功添加了学生:"+students.get(Id).getName());
                i++;
            }else{
                show("该学生Id已被占用");
                continue;
            }
        }
    }

    //获取键值对
    public void getKeySet(){
        Set<String> keyset = students.keySet();
        show("总有"+students.size()+"个学生");
        for(String id:keyset){
            Student st = students.get(id);
            if(st!=null){
                show("学生："+st.getName());
            }
        }
    }

    //删除键值对
    public void removeKey(){
        while(true){
            show("请输入要删除学生的Id：");
            String Id = console.next();
            Student st = students.get(Id);
            if(st==null){
                show("学生信息不存在！");
                continue;
            }
            students.remove(Id);
            show("成功删除学生"+st.getName());
            break;
        }
    }

    //遍历集合
    public void printEntrySet(){
        Set<Entry<String, Student>> entryset = students.entrySet();
        for(Entry<String,Student>entry:entryset){
            show("取得的键值："+entry.getKey());
            show("取得的值："+entry.getValue().toString());
        }
    }

    //修改键值对
    public void setKey(){

        while(true){
            show("请输入要修改的学生Id：");
            String Id = console.next();
            Student st = students.get(Id);
            if(st==null){
                show("学生不存在，请重新输入");
                continue;
            }
            show("当前学生Id对应的学生姓名："+st.getName());
            show("请重新输入学生姓名：");
            String newName = console.next();
            Student nst = new Student(Id,newName);
            students.put(Id, nst);
            show("修改学生成功！");
            getKeySet();
            break;

        }
    }

    public void test(){
        students.containsValue(new Student(null,"001"));
    }

    public static void show(Object obj){
        System.out.println(obj.toString());
    }
}

Index.java

package dk.main;

import dk.courses.Course;
import dk.courses.CourseList;
import dk.students.Student;

public class Index {
    public static void main(String[] args){
        //CourseList list = new CourseList();
        CourseList.show("开始添加课程");
        CourseList.show("=========================================================");
        CourseList.addCourse("001","Java课程设计");
        CourseList.addCourse("002","数据结构");
        CourseList.addCourse("003","高等数学");
        CourseList.addCourse("004","Java课程设计");
        CourseList.addCourse("005","计算机网络基础");
        CourseList.getAllCourse();
        CourseList.setCourse("001", "C语言程序设计");
        CourseList.getAllCourse();
        Course c = CourseList.getCourse("002");
        Course c1 = new Course("0088",c.getName());
        CourseList.show(CourseList.getCourseIndex(c1));
        //Course c = CourseList.getCourse("001");
        //Course c1 = new Course(c.getId(),c.getName());
        CourseList.show(CourseList.containCourse(c1));
        CourseList.removeCourse("004");
        //CourseList.removeAllCourse();
        CourseList.show(c.toString());
        CourseList.getAllCourse();
        Student s = new Student("007","DekingChen");
        s.selectCourses("001");
        s.selectCourses("002");
        s.selectCourses("003");
        s.selectCourses("005");
        s.removeCourse("003");
        s.printCourses();

    }
}

运行结果：

开始添加课程
=========================================================
添加了课程：  课程编号：001    课程名称：Java课程设计
添加了课程：  课程编号：002    课程名称：数据结构
添加了课程：  课程编号：003    课程名称：高等数学
添加了课程：  课程编号：004    课程名称：Java课程设计
添加了课程：  课程编号：005    课程名称：计算机网络基础
=========================================================
课程列表如下：(共有5门课程)
=========================================================
课程编号：001    课程名称:Java课程设计
课程编号：002    课程名称:数据结构
课程编号：003    课程名称:高等数学
课程编号：004    课程名称:Java课程设计
课程编号：005    课程名称:计算机网络基础
=========================================================
=========================================================
课程列表如下：(共有5门课程)
=========================================================
课程编号：001    课程名称:C语言程序设计
课程编号：002    课程名称:数据结构
课程编号：003    课程名称:高等数学
课程编号：004    课程名称:Java课程设计
课程编号：005    课程名称:计算机网络基础
=========================================================
1
true
课程编号：002    课程名称:数据结构
=========================================================
课程列表如下：(共有4门课程)
=========================================================
课程编号：001    课程名称:C语言程序设计
课程编号：002    课程名称:数据结构
课程编号：003    课程名称:高等数学
课程编号：005    课程名称:计算机网络基础
=========================================================
您选择了以下课程：
课程编号：001    课程名称:C语言程序设计
您选择了以下课程：
课程编号：002    课程名称:数据结构
您选择了以下课程：
课程编号：003    课程名称:高等数学
您选择了以下课程：
课程编号：005    课程名称:计算机网络基础
=========================================================
学号：007  姓名：DekingChen   共选择了门3课
=========================================================
课表如下:
课程编号：001    课程名称:C语言程序设计
课程编号：002    课程名称:数据结构
课程编号：005    课程名称:计算机网络基础
=========================================================