java:类集操作,多对多的关系

 

//一个课程有多个学生报名，

//一个学生可以报名多个课程

 

 

demo.java, Student.java, Course.java'

public class Course {	private String name;	private int course;	private List
     
       allStudent;				public Course() {		this.allStudent = new ArrayList
      
       ();	}	public Course(String name, int course) {		this();		this.name = name;		this.course = course;	}	public String getName() {		return name;	}		public void setName(String name) {		this.name = name;	}		public int getCourse() {		return course;	}		public void setCourse(int course) {		this.course = course;	}		public List
       
         getAllStudent() {		return allStudent;	}			public String toString()	{		return "课程："+this.name +",学分："+this.course;	}								}
       
      
     

　　

Student.java

public class Student {	private String name;	private int age;	private List
     
       allCourse;								public Student() {		this.allCourse = new ArrayList
      
       ();	}	public Student(String name, int age) {		this();		this.name = name;		this.age = age;			}	public String getName() {		return name;	}			public void setName(String name) {		this.name = name;	}			public int getAge() {		return age;	}			public void setAge(int age) {		this.age = age;	}			public List
       
         getAllCourse() {		return allCourse;	}	public String toString()	{		return "学生："+this.name + ",年龄："+this.age;	}					}
       
      
     

　　

demo.java

//一个学生可以报名多个课程		Course c1 = new Course("java",5);		Course c2 = new Course("linux",5);				Student st1 = new Student("张三",22);		Student st2 = new Student("李四",33);		Student st3 = new Student("王五",32);		Student st4 = new Student("田七",29);		Student st5 = new Student("赵六",28);				//第一课程		c1.getAllStudent().add(st1);		c1.getAllStudent().add(st3);		st1.getAllCourse().add(c1);		st2.getAllCourse().add(c2);				//第二课程		c2.getAllStudent().add(st1);		c2.getAllStudent().add(st2);		c2.getAllStudent().add(st3);		c2.getAllStudent().add(st4);		c2.getAllStudent().add(st5);		st1.getAllCourse().add(c2);		st2.getAllCourse().add(c2);		st3.getAllCourse().add(c2);		st4.getAllCourse().add(c2);		st5.getAllCourse().add(c2);				//输出		System.out.println(c1);		Iterator
     
       stu = c1.getAllStudent().iterator();				while(stu.hasNext())		{			System.out.println("__" + stu.next());		}		System.out.println(st1);		Iterator
      
        cour = st1.getAllCourse().iterator();				while(cour.hasNext())		{			System.out.println( "__" + cour.next());		}
      
     

　　

 

输出的结果为：

课程：java,学分：5__学生：张三,年龄：22__学生：王五,年龄：32学生：张三,年龄：22__课程：java,学分：5__课程：linux,学分：5