Map子类TreeMap问题 - 黑马程序员技术交流社区

package cn.itcast.day1;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeMap;
class StuNameComparator implements Comparator<Student> {
/* 按照姓名排序，如果姓名相同，那么按照年龄排序 */
public int compare(Student o1, Student o2) {
int num = o1.getName().compareTo(o2.getName());
if (num == 0) {
return o1.getAge() - o2.getAge();
}
return num;
}
}
class Student /* implements Comparable<Student> */{// 十七具有比较性，防止排序的出现异常
private String name;// 姓名
private int age;// 年龄
public Student(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
/*
// 重写hashCode()方法
public int hashCode() {
return this.name.hashCode() + this.age * 12;
}
//重写equals方法
public boolean equals(Object ob) {
if (!(ob instanceof Student))
throw new ClassCastException("不是Student对象");
Student stu = (Student) ob;
return this.name.equals(stu.getName()) && this.age == stu.getAge();
}
// 覆写CompareTo方法先比较年龄，然后比较姓名
public int compareTo(Student stu) {
int num = this.age - stu.age;
if (num == 0) {
return this.name.compareTo(stu.name);
}
return num;
}
*/
}
public class TreeMapDemo {
public static void main(String[] args) {
/* 定义HashMap，里面存储的是Student和地址 */
TreeMap<Student, String> map = new TreeMap<Student, String>(
new StuNameComparator());
map.put(new Student("java03", 23), "北京");
map.put(new Student("net02", 21), "上海");
map.put(new Student("net02", 26), "厦门");
map.put(new Student("net03", 26), "广州");
map.put(new Student("java01", 24), "南京");
map.put(new Student("java01", 22), "天津");
map.put(new Student("net03", 26), "广州");
Set<Student> set = map.keySet();
Iterator<Student> it = set.iterator();
while (it.hasNext()) {
Student stu = it.next();
String name = stu.getName();
int age = stu.getAge();
String address = map.get(stu);
System.out.println(name + ":" + age + ":" + address);
}
}
}

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