Question

HashSet存入对象怎么取出对象的值

我的代码如下：
public class HashSetTest{
public static void main(String args[]){
Student s1 = new Student(1,"zhang san1");
Student s2 = new Student(2,"zhang san2");
Student s3 = new Student(3,"zhang san3");
Student s;
Set hs = new HashSet();
hs.add(s1);
hs.add(s2);
hs.add(s3);
Iterator it = hs.iterator();
while(it.hasNext())
System.out.println(it.next());
}
}
class Student{
int num;
String name;
Student(int num,String name){
this.num = num;
this.name = name;
}
}

不知道怎样从hs中取出studnt对象的值，请大家指点一下。

Answer 1

你是想说输出num和name么；两种方法：
一
Iterator it = hs.iterator();
while(it.hasNext())
Student s = (Student)it.next();
System.out.println(s.num+"NAME : "+s.name);
}
二 在Student类中复写toString()方法：
class Student{
int num;
String name;
Student(int num,String name){
this.num = num;
this.name = name;
}
public String toStrong(){
return "num :"+this.num +" name: "+this.name ;
}
}
采用二方法较佳，此时直接输出对象即可；
while(it.hasNext())
Student s = (Student)it.next();//需要强制转换
System.out.println(s);
}

Answer 2

Iterator it = hs.iterator();
while(it.hasNext())
//System.out.println(it.next());
Student s = (Student)it.next();
}

Answer 3

Iterator iterator = set.iterator();
while(iterator.hasNext()){
Student student = (Student)iterator.next();
}