Object

 
class Person
{
	int age;
	String name;
	public Person(int age, String name)
	{
		this.age = age;
		this.name = name;
	}
	public Person()
	{
	}
	public String toString()
	{
		return "年龄"+ age+"  姓名："+name; 
	}
	public boolean equals(Object o)		//重写equals来判断两个人的年龄是否相同
	{
		Person p  =(Person)o; 
		return this.age==p.age;
	}
	//一般重写了equals方法就要重写hashCode方法
	public int hashCode()
	{
		return this.age;
	}
}


public class Object1
{
	public static void main(String[] args)
	{
		Object o = new Object();
		System.out.println(o);
		System.out.println(o.toString());
		
		Person p1 = new Person(18,"张三");
		Person p2 = new Person(18,"李四");
		System.out.println("p1   "+ p1);
		System.out.println("p2   "+ p2);
		
		Person p3 = new Person(18,"王麻子");
		System.out.println("p1和p3是同一个年龄吗？ "+p1.equals(p3));
		
		System.out.println("p1.hashCode() = "+ p1.hashCode());
		System.out.println("p2.hashCode() = "+ p2.hashCode());
	}
}

运行结果：


java.lang.Object@52ed3bff
java.lang.Object@52ed3bff
p1   年龄18  姓名：张三
p2   年龄18  姓名：李四
p1和p3是同一个年龄吗？ true
p1.hashCode() = 18
p2.hashCode() = 18