TreeSet 练习

import java.util.*;class MapTest{public static void main(String[] args) {TreeMap<Student,String> map=new TreeMap<Student,String>(new MyCompara());map.put(new Student("java01",26),"beijing");map.put(new Student("java03",22),"nanjing");map.put(new Student("java04",24),"haerbin");map.put(new Student("java02",21),"hegang");map.put(new Student("java05",20),"jiangbin");map.put(new Student("java02",21),"hegang");map.put(new Student("java05",20),"jiangbin");        Set<Map.Entry<Student,String>> entrySet=map.entrySet();Iterator<Map.Entry<Student,String>> it=entrySet.iterator();while(it.hasNext()){Map.Entry<Student,String> me=it.next();Student stu=me.getKey();String addr=me.getValue();System.out.println(stu+":::"+addr);}}}class Student implements Comparable<Student>{private String name;private int age;public int compareTo(Student s){int n=new Integer(this.age).compareTo(new Integer(s.age));if(n==0){return this.name.compareTo(s.name);}return n; }public int hashCode(){return name.hashCode()+age;}public boolean equals(Object obj){        if(!(obj instanceof Student)){            throw new ClassCastException("类型不匹配");}Student s=(Student)obj;    return this.name.equals(s.name)&& this.age==s.age;}Student(String name,int age){        this.name=name;this.age=age;}public String getName(){return name;}public int getAge(){return age;}public String toString()//重写后解决 年龄输出为哈希值问题{return name+" "+age;}}class MyCompara implements Comparator<Student>{     public int compare(Student s1,Student s2) {         int n=s1.getName().compareTo(s2.getName()); if(n==0) { return new Integer(s1.getAge()).compareTo(new Integer(s2.getAge())); } return n; }}