多对对的映射，可以用学生和课程进行演示。一个学生可以选择多个课程，一个课程又对应了多个学生
定义学生类
class Stu{
private String name;
private String num;
private Course[] course;
public Stu() {}
public Stu(String name,String num) {
this.name = name;
this.num = num;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getNum() {
return num;
}
public void setNum(String num) {
this.num = num;
}
public Course[] getCourse() {
return course;
}
public void setCourse(Course[] course) {
this.course = course;
}
public String getInfo() {
return "姓名 :"+name+" 学号 :"+num;
}
}定义课程 类
class Course{
private String name;
private Stu[] stu;
public Course() {}
public Course(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Stu[] getStu() {
return stu;
}
public void setStu(Stu[] stu) {
this.stu = stu;
}
public String getInfo() {
return "课程 :"+name;
}
}在main方法测试
首先定义Stu和Course对象，分别有三个
Stu s1 = new Stu("张三","001");
Stu s2 = new Stu("李四","002");
Stu s3 = new Stu("王五","003");
Course c1 = new Course("Java");
Course c2 = new Course("php");
Course c3 = new Course("Python");设置彼此的关系，每个对象都有多个对象对应
//设置学生和课程的关系
s1.setCourse(new Course[]{c1,c2});
s2.setCourse(new Course[]{c1,c3});
s3.setCourse(new Course[]{c2,c3}); //相应的课程设置与学生的关系
c1.setStu(new Stu[]{s1,s2});
c2.setStu(new Stu[]{s1,s3});
c3.setStu(new Stu[]{s2,s3});
根据学生，获取课程信息
System.out.println(s1.getInfo()+" 同学选择的课程有");
for(int i=0; i<s1.getCourse().length; i++) {
System.out.println(s1.getCourse()[i].getInfo());
}
运行
根据课程，获取学生信息
System.out.println(c2.getInfo()+" 选择这门课程的学生信息");
for(int i=0; i<c2.getStu().length; i++) {
System.out.println(c2.getStu()[i].getInfo());
}
运行