关于hasCode,和equal的问题,求各位大神帮忙
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
public class Person {
private String name;
private long ID;
public Person(String name,long ID) {
this.name=name;
this.ID=ID;
}
public long getID() {
return ID;
}
public void setID(long ID) {
this.ID=ID;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name=name;
}
public int hasCode() {
final int PRIME=31;
int result=1;
result=PRIME*result+(int)(ID^(ID>>>32));
result=PRIME*result+((name==null)?0:name.hashCode());
return result;
}
public boolean equals(Object obj) {
if(this==obj)
return true;
if(obj==null)
return false;
if(getClass()!=obj.getClass())
return false;
final Person other=(Person)obj;
if(ID!=other.ID)
return false;
if(name==null) {
if(other.name!=null)
return false;
}
else if(!name.equals(other.name))
return false;
return true;
}
public static void main(String[] args) {
Set<Person>hashSet=new HashSet<Person>();
hashSet.add(new Person("马先生",220181));
hashSet.add(new Person("李先生",220186));
hashSet.add(new Person("王小姐",220193));
Iterator<Person>it=hashSet.iterator();
while(it.hasNext()) {
Person person=it.next();
System.out.println(person.getName()+""+person.getID());
}
}
}
我一直搞不懂,equal和hasCode方法是如何运行的 , 例如equal this=obj,这个this到底指的是什么,obj他指定的又是什么?