set集合怎么去除重复的对象_J2SE

set集合如何去除重复的对象
面试的时候碰到这样一个问题，不太明白

Java code

User u1 = new User();u1.name="aa";u1.password = "11";User u2 = new User();u2.name = "bb";u2.password = "22";Set sets = new HashSet();sets.add(u1);sets.add(u2);

是类似这样的去重复吗？

------解决方案--------------------

Java code

public class User{  @Override  public String toString(){    return this.name;  }  @Override String hashCode(){    return User.class.toString()+toString();  }  @Override boolean equals(Object object){    if(object==null) return this==null;    return object.toString().equals(toString());  }}
------解决方案--------------------
上面给出了部分代码，现在给出set的全部代码，中间有代码的验证部分。试验结果是
1
[Name :bb  Password:22]

Java code import java.util.*;public class TestSet {    public static void main(String[] args) {        User u1 = new User("aa","11");                 User u2 = new User("bb","22");        Set sets = new HashSet();        sets.add(u1);        sets.add(u2);        sets.remove(u1);//删除点一个User对象，然后进行验证  试验结果成功        System.out.println(sets.size());        System.out.println(sets);    }}class User{    String name;    String password;    User(String name,String password){        this.name=name;        this.password=password;    }    public String toString(){        return "Name :"+name+"  "+"Password:"+password;    }    public boolean equals(Object obj){         if(obj instanceof User){         User user=(User)obj;         return (name.equals(user.name))&&(password.equals(user.password));         }         return super.equals(obj);     }     public int hashCode(){         return name.hashCode();     }}