Java: Skill: List sort

最新推荐文章于 2025-04-19 09:45:00 发布

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#java #list #sort #comparable #comparator

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本文深入探讨了如何使用Java对List进行排序。通过实现Comparable接口和使用Comparator进行排序，提供了详细的Person实体类例子及测试结果。

Java List sort

Array

Arrays.sort

List

java.util.Collections.sort(java.util.List)

java.util.Collections.sort(java.util.List, java.util.Comparator)

Examples for List sort

1. Implements Comparable interface

(1). Person entity class

public class Person implements Comparable<Person> {
    private String name;
    private Integer order;
 
    /**
     * @return the name
     */
    public String getName() {
        return name;
    }
 
    /**
     * @param name
     *            the name to set
     */
    public void setName(String name) {
        this.name = name;
    }
 
    /**
     * @return the order
     */
    public Integer getOrder() {
        return order;
    }
 
    /**
     * @param order
     *            the order to set
     */
    public void setOrder(Integer order) {
        this.order = order;
    }
 

    @Override
    public int compareTo(Person arg0) {
        return this.getOrder().compareTo(arg0.getOrder());      //这里定义你排序的规则。
    }
 
}

(2). Test class

public static void main(String[] args) {
    //初始化数据
    List<Person> listA = new ArrayList<Person>();
    Person p1 = new Person();
    Person p2 = new Person();
    Person p3 = new Person();
 
    p1.setName("name1");
    p1.setOrder(1);
    p2.setName("name2");
    p2.setOrder(2);
    p3.setName("name3");
    p3.setOrder(3);
 
    listA.add(p2);
    listA.add(p1);
    listA.add(p3);

    //排序
    Collections.sort(listA);

    //打印排序后的Person
    for (Person p : listA) {
        System.out.println(p.getName());
    }
}

(3). Test results

name1
name2
name3

2. java.util.Collections.sort(java.util.List, java.util.Comparator)

(1). Person entity class

public class Person {
    private String name;
    private Integer order;
 
    /**
     * @return the name
     */
    public String getName() {
        return name;
    }
 
    /**
     * @param name
     *            the name to set
     */
    public void setName(String name) {
        this.name = name;
    }
 
    /**
     * @return the order
     */
    public Integer getOrder() {
        return order;
    }
 
    /**
     * @param order
     *            the order to set
     */
    public void setOrder(Integer order) {
        this.order = order;
    }
 
}

(2). Test class

public static void main(String[] args) {
        List<Person> listA = new ArrayList<Person>();
        Person p1 = new Person();
        Person p2 = new Person();
        Person p3 = new Person();
 
        p1.setName("name1");
        p1.setOrder(1);
        p2.setName("name2");
        p2.setOrder(2);
        p3.setName("name3");
        p3.setOrder(3);
 
        listA.add(p2);
        listA.add(p1);
        listA.add(p3);
         
        //直接在这里添加我们的排序规则
        Collections.sort(listA, new Comparator<Person>() {
            public int compare(Person arg0, Person arg1) {
                return arg0.getOrder().compareTo(arg1.getOrder());
            }
        });
         
        for (Person p : listA) {
            System.out.println(p.getName());
        }
    }