/*

 * 学生属性：姓名，年龄

 * 注意：姓名和年龄相同的视为同意学生

 * 

 * 

 * 1, 描述学生

 * 2， 定义map容器，将学生作为键，地址作为值，存入

 * 3， 获取集合元素

 * 

 * 

 * */

import java.util.HashMap;

import java.util.Iterator;

import java.util.Set;

public class HashMapDemo {

public static void main(String[] args) {

HashMap<student,String> hm=new HashMap<student,String>();

hm.put(new student("zhangsan",21), "nanna2");

hm.put(new student("lisi",26), "nanna1");

hm.put(new student("wangwu",22), "nanna3");

Set<student> set=hm.keySet();

Iterator<student> it=set.iterator();

while (it.hasNext()) {

student stu=it.next();

String adr=hm.get(stu);

System.out.println(stu+"     "+adr);

}

}

}

class student implements Comparable<student>{

public int hashcode() {

return name.hashCode()+age*34;

}

public boolean equals(Object obj) {

if(!(obj instanceof student))

throw new ClassCastException("");

student student= (student)obj;

return this.name.equals(student.name)&& this.age==student.age;

}

public String toString() {

return "student [name=" + name + ", age=" + age + "]";

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

private String name;

private int age;

public student() {

}

student(String name,int age){

name=this.name;

age=this.age ;

}

public int compareTo(student s) {

int num=new Integer(this.age).compareTo(new Integer(s.age));

if(num==0)

return this.name.compareTo(s.name);

return num;

}

}

输出结果：

student [name=null, age=0]     nanna1

student [name=null, age=0]     nanna2

student [name=null, age=0]     nanna3