JAVA HASHMAP 用法

import java.util.HashMap;
public class Student {
String name;
String sex;
public Student(String n,String s) {
name=n;
sex=s;
}
public String toString(){
return ("姓名:"+name+"\n"+"性别:"+sex+"\n");
}
public static void main(String [] args){
HashMap hm=new HashMap();
Student s1=new Student("张三","男");
Student s2=new Student("李四","男");
Student s3=new Student("小利","女");

//存值是根据学生编号存的学生信息
hm.put("001",s1);
hm.put("002",s2);
hm.put("003",s3);

//查找学生编号是001的学生

//因为hm.get("001")反回的是Object所以加上强转
Student s=(Student)hm.get("001");
System.out.println(s.toString());

//其余的类似

}
}