java list排序小问题

```java
package com.collection;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class ListSort {
    public static void main(String[] args) {
        List list=new ArrayList();
        list.add(new Book1("西游记",123.2,"吴承恩"));
        list.add(new Book1("红楼梦",156.5,"曹雪芹"));
        list.add(new Book1("三国演义",152.2,"罗贯中"));
        for (int i = 0; i < list.size()-1; i++)
        {
            for(int j=0;j<list.size()-i-1;j++)
            {
                Book1 book1=(Book1)list.get(j);
                Book1 book2=(Book1)list.get(j+1);
                if(book1.getPrice()>book2.getPrice())
                {
                    list.set(j,book2);
                    list.set(j+1,book1);
                }
            }
        }
        for (Object obj:list
             ) {
            System.out.println(obj);
        }
        Iterator it=list.iterator();
        while (it.hasNext()) {
            System.out.println(it.next());
        }



    }
}
class Book1
{
    private String name;
    private double price;
    private String author;

    public Book1(String name, double price, String author) {
        this.name = name;
        this.price = price;
        this.author = author;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

}
//结果如下 
//com.collection.Book1@4554617c
//com.collection.Book1@74a14482
//com.collection.Book1@1540e19d
//com.collection.Book1@4554617c
//com.collection.Book1@74a14482
//com.collection.Book1@1540e19d

为啥运行结果是hash码 而不是对象的属性

需要重写toSting方法

重写Book1的toString()方法