真心求教comparable接口问题，求解释 - 黑马程序员技术交流社区

package 集合框架1;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.TreeMap;
class Student implements Comparable<Student>
{
private String name;
private int age;
Student(String name, int age)
{
this.setName(name);
this.setAge(age);
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int compareTo(Student stu) {
if(stu.age>this.age)
{
return 1;
}
if(stu.age<this.age)
{
return -1;
}
return stu.name.compareTo(this.name);
}
}
public class MapDemo2 {
public static void main(String[] args) {
TreeMap<String , List> jiangzhi = new TreeMap<String , List>();
ArrayList<Student> yidong = new ArrayList<Student>();
ArrayList<Student> diansheng = new ArrayList<Student>();
yidong.add(new Student("张翔",45));
yidong.add(new Student("犬夜叉",20));
yidong.add(new Student("张翔",45));
diansheng.add(new Student("刘翔",40));
diansheng.add(new Student("子健",20));
diansheng.add(new Student("刘翔",40));
jiangzhi.put("yidong", yidong);
jiangzhi.put("diansheng", diansheng);
jiangzhiIterator(jiangzhi);
}
private static void jiangzhiIterator(TreeMap<String, List> jiangzhi) {
// TODO Auto-generated method stub
Iterator<String> it = jiangzhi.keySet().iterator();
while(it.hasNext()){
String key = it.next();
List<Student> room = jiangzhi.get(key);
System.out.println("班级:"+key);
roomIterator(room);
}
}
private static void roomIterator(List room) {
// TODO Auto-generated method stub
Iterator it = room.iterator();
while(it.hasNext())
{
Student stu = (Student) it.next();
System.out.println(stu.getName()+"..."+stu.getAge());
}
}
}

复制代码