Question

JAVA 数组中的元素是对象,如何给对象排序

我用数组存储了一些对象(书),每本书都有自己的价格,如何根据书本的价格给书本升序排列呢?比如我在数组中存了三本书, 第一本:name:javaEE, price:10 第二本:name:javaSe ,price:5 第三本:name:javaMe ,price:12 如何根据他们的价格升序排列出来呢?

Answer 1

写那么麻烦干什么呢，看我的！

Book[] books = { new Book("j2me",12), new Book("j2se",5), new Book("j2ee",22) };
Arrays.sort (books, new Comparator<Book> ()
{
    @Override
    public int compare ( Book o1, Book o2 )
    {
        if (o1.getPrice()  > o2.getPrice() )
        {
            return 1;
        }
        else if (o1.getPrice()  < o2.getPrice() )
        {
            return -1;
        }
        else
        {
            return 0;
        }
    }
});

Answer 2

implements Comparator；

重写int compareTo（Book b）｛
return this.price - b.getPrice()；

｝

然后Collentions.sort(bookList);

Answer 3

import java.util.Arrays;

public class TreeSet1
{

public static void main(String[] args)
{
Book[] books = {new Book("j2me",12),new Book("j2se",5),new Book("j2ee",22)};

Arrays.sort(books);
System.out.println(Arrays.toString(books));
}
}

class Book implements Comparable<Book>
{
private String name;
private int price;
@Override
public String toString()
{
return "Book [name=" + name + ", price=" + price + "]";
}
public Book(String name, int price)
{
super();
this.name = name;
this.price = price;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getPrice()
{
return price;
}
public void setPrice(int price)
{
this.price = price;
}
@Override
public int compareTo(Book o)
{

return this.getPrice() - o.getPrice();
}

}

Answer 4

重写Comparator接口