java set集合学习-(慕课网代码)_java如何将set<course>变成course[]-优快云博客

本文介绍了一个简单的学生选课系统的实现方法，通过定义课程和学生类，并使用集合存储课程信息，实现了学生选课功能及选课结果展示。

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course类：

import javax.print.DocFlavor.STRING;

//课程类
public class Course {
public String id;
public String name;

public Course(String id,String name) {//含参构造器
	this.id=id;
	this.name=name;
	
}
}

student 类：

import java.util.HashSet;
import java.util.Set;

public class Student {
public String id;
public String name;
public Set<Course> course;
public Student(String id,String name) {
	this.id=id;
	this.name=name;
	this.course= new HashSet<Course>();  //创建选课集合
}
}

测试类：

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Settest {

	 public static List <Course>courseToSelect;//定义list中存放着course类型信息
	 
	 public Settest() {   //存放选课信息
		 courseToSelect= new ArrayList<Course>();
	 }
	 
	 public void testAdd() {  
			//调用add方法添加课程course到list集合
			Course cr1 = new Course("1", "数据结构");
			courseToSelect.add(0, cr1);
			//测试输出
//			Course temp =(Course) courseToSelect.get(0);
//			System.out.println("添加的课程: "+ temp.id+" "+temp.name);
			Course cr2 = new Course("2", "c语言");
			courseToSelect.add(0, cr2);
//			Course temp2 =(Course) courseToSelect.get(0);
//			System.out.println("添加的课程: "+ temp2.id+" "+temp2.name);

		    Course [] course= {new Course("3", "离散数学"),new Course("4", "汇编语言 ")};
		    //将course数组中所有课程添加入list
		    courseToSelect.addAll(Arrays.asList(course));
		    Course temp3=(Course)courseToSelect.get(2);
		    Course temp4=(Course)courseToSelect.get(3);
//			System.out.println("添加的课程: "+ temp3.id+" "+temp3.name);
//			System.out.println("添加的课程: "+ temp4.id+" "+temp4.name);
			
			Course [] course2= {new Course("5", "高等数学"),new Course("6", "大学英语 ")};
			courseToSelect.addAll(2,Arrays.asList(course2));
			Course temp5=(Course)courseToSelect.get(2);
		    Course temp6=(Course)courseToSelect.get(3);
//			System.out.println("添加的课程: "+ temp5.id+" "+temp5.name);
//			System.out.println("添加的课程: "+ temp6.id+" "+temp6.name);
//			
			
		}
	 public void testforeach() {
			for(Object obj: courseToSelect) {
				Course cr = (Course)obj;
				System.out.println("课程"+cr.id+":"+cr.name);

			}
		}
	 
	public static void main(String[] args) {
		Settest st = new Settest();
		st.testAdd();
		st.testforeach();//遍历输出参考选课
		
		Student stu1 = new Student("1","小明");
		
		System.out.println("欢迎选课");
		Scanner console = new Scanner(System.in);
		
		//输入选课id 与 list中课程对比，匹配后加入stu的set集合中
		for(int i = 0;i<3;i++) { 
			System.out.println("请输入选课的id");
			String courseid = console.next();
			for(Course cr:courseToSelect) {
				
				if(cr.id.equals(courseid)) {
					stu1.course.add(cr);
				}
			}		
		}
		
		//输出选择的课程信息
		System.out.println("共选择了"+stu1.course.size()+"门课程");
		for(Course cr:stu1.course) {
			System.out.println("选择了"+cr.id+" "+cr.name);
			
		}
		
	}

}