举个例子:
现在有一个学生类
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
}
}