如何在Java中对ArrayList进行排序

Question

我有一个名为Fruit的课程.我正在创建此类的列表并在列表中添加每个水果.我想根据水果名称的顺序对此列表进行排序.

public class Fruit{

    private String fruitName;
    private String fruitDesc;
    private int quantity;

    public String getFruitName() {
        return fruitName;
    }
    public void setFruitName(String fruitName) {
        this.fruitName = fruitName;
    }
    public String getFruitDesc() {
        return fruitDesc;
    }
    public void setFruitDesc(String fruitDesc) {
        this.fruitDesc = fruitDesc;
    }
    public int getQuantity() {
        return quantity;
    }
    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }
}

我正在使用for循环创建它的列表

List<Fruit>  fruits= new ArrayList<Fruit>();

Fruit fruit;
for(int i=0;i<100;i++)
{
   fruit = new fruit();
   fruit.setname(...);
   fruits.add(fruit);
}

我需要使用列表中每个对象的水果名称对此arrayList进行排序

怎么样？？

Answer 1

使用Comparator这样的:

List<Fruit> fruits= new ArrayList<Fruit>();

Fruit fruit;
for(int i = 0; i < 100; i++)
{
  fruit = new Fruit();
  fruit.setname(...);
  fruits.add(fruit);
}

// Sorting
Collections.sort(fruits, new Comparator<Fruit>() {
        @Override
        public int compare(Fruit fruit2, Fruit fruit1)
        {

            return  fruit1.fruitName.compareTo(fruit2.fruitName);
        }
    });

现在你的水果列表是根据fruitName.

Answer 2

实现Fruit的Comparable接口.

public class Fruit implements Comparable<Fruit> {

它实现了该方法

@Override
    public int compareTo(Fruit fruit) {
        //write code here for compare name
    }

然后调用sort方法

Collections.sort(fruitList);

Answer 3

试试BeanComparator

import org.apache.commons.beanutils.BeanComparator;


BeanComparator fieldComparator = new BeanComparator("fruitName");
Collections.sort(fruits, fieldComparator);