想了一下午的问题，供大家一起研究研究。 - 黑马程序员技术交流社区

import java.util.*;
class Student implements Comparable<Student>
{
private String name;
private int no;
Student(int no,String name)
{
this.no = no;
this.name = name;
}
public int compareTo(Student s)
{
int num = new Integer(this.no).compareTo(new Integer(s.no));
if (num==0)
{
return this.name.compareTo(s.name);
}
return num;
}
public int hashCode()
{
return 1;
}
public boolean equals(Object obj)
{
if(!(obj instanceof Student))
throw new ClassCastException("您输入的与所需类型不匹配");
Student s =(Student)obj;
return this.no==s.no && this.name.equals(s.name);//
}
public String getName()
{
return name;
}
public int getNo()
{
return no;
}
public String toString()
{
return "no:"+no+" name:"+name;
}
}
class StudentNoComparator implements Comparator<Student>
{
public int compare(Student s1,Student s2)
{
return s1.compareTo(s2);
}
}
class Noname3
{
public static void main(String[] args)
{
TreeMap<Student,Integer> hm = new TreeMap<Student,Integer>(new StudentNoComparator());//
hm.put(new Student(04,"student4"),24);
hm.put(new Student(02,"student2"),22);
hm.put(new Student(03,"student3"),23);
hm.put(new Student(01,"student1"),21);
hm.put(new Student(05,"student5"),25);
System.out.println();
Set<Map.Entry<Student,Integer>> entrySet = hm.entrySet();
Iterator<Map.Entry<Student,Integer>> iter = entrySet.iterator();
while (iter.hasNext())
{
Map.Entry<Student,Integer> me = iter.next();
Student stu = me.getKey();
Integer age = me.getValue();
System.out.println(stu+" age:"+age);
}
}
}

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