package First;

import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;

import bean.Person;

public class Dream {
public static void main(String args[])
{
LinkedHashSet h1=new LinkedHashSet();
h1.add(new Person("xiao1",1));
h1.add(new Person("xiao3",3));
h1.add(new Person("xiao2",2));
h1.add(new Person("xiao3",3));
Iterator it=h1.iterator();

    while(it.hasNext())
    {
        Person p=(Person) it.next();
        System.out.println(p.getName()+".."+p.getAge());
    }

}

}
package bean;

public class Person {
private String name;
private int age;
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

public int hashCode() 
{

        return name.hashCode()+age;
}
public boolean equals(Object obj)
{

    Person p=(Person)obj;
    return this.name.equals(p.name) && this.age==p.age;
}

}
看不懂person类重写的equals方法。请详细讲解一下，还有就是在执行h1.add(new Person("xiao1",1));这种代码时，谁去调用了hashcode（）和equals（）？过程讲解一下.最大的疑惑在于equals方法中obj只和调用equals方法的对象做了对比，不是只有一次吗？只能判断出一个对象不与其重复吗？

a1670131049

java集合框架hashset重写equals的问题

2条回答

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