如何在 Java 中对 ArrayList 进行排序
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How to sort an ArrayList in Java
提问by ranjith
I have a class named Fruit. I am creating a list of this class and adding each fruit in the list. I want to sort this list based on the order of fruit name.
我有一个名为 Fruit 的类。我正在创建此类的列表并将每个水果添加到列表中。我想根据水果名称的顺序对这个列表进行排序。
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;
}
}
and I am creating its list using for loop
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);
}
and I need to sort this arrayList using the fruit name of each object in the list
我需要使用列表中每个对象的水果名称对这个 arrayList 进行排序
how??
如何？？
采纳答案by Prabhakaran Ramaswamy
Use a Comparatorlike this:
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);
}
});
Now your fruits list is sorted based on fruitName.
现在您的水果列表基于fruitName.
回答by bNd
Implement Comparableinterface to Fruit.
实现与Fruit 的Comparable接口。
public class Fruit implements Comparable<Fruit> {
It implements the method
它实现了方法
@Override
public int compareTo(Fruit fruit) {
//write code here for compare name
}
Then do call sort method
然后调用排序方法
Collections.sort(fruitList);
回答by newuser
Try BeanComparatorfrom Apache Commons.
试试Apache Commons 的BeanComparator。
import org.apache.commons.beanutils.BeanComparator;
BeanComparator fieldComparator = new BeanComparator("fruitName");
Collections.sort(fruits, fieldComparator);
