list按照某个元素进行排序

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Sort {

    private int age ;

    private String name;

    public Sort(int age, String name) {
        this.age = age;
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "Sort{" +
                "age=" + age +
                ", name=" + name +
                '}';
    }

    public static void main(String args[]) {


        List<Sort> sorts = new ArrayList<>();

        sorts.add(new Sort(18,"ww"));
        sorts.add(new Sort(12,"wf"));
        sorts.add(new Sort(13,"wg"));
        sorts.add(new Sort(19,"wa"));
        sorts.add(new Sort(16,"wb"));


        System.out.println("排序前的结果："+sorts.toString());
        Collections.sort(sorts, new Comparator<Sort>(){
            /*
             * int compare(Person p1, Person p2) 返回一个基本类型的整型，
             * 返回负数表示：p1 小于p2，
             * 返回0 表示：p1和p2相等，
             * 返回正数表示：p1大于p2
             */
            public int compare(Sort p1, Sort p2) {
                //按照Person的年龄进行升序排列
                if(p1.age > p2.age){
                    return 1;
                }
                if(p1 == p2){
                    return 0;
                }
                return -1;
            }
        });
        System.out.println("排序后的结果："+sorts.toString());

    }
}

 

执行结果：

排序前的结果：[Sort{age=18, name=ww}, Sort{age=12, name=wf}, Sort{age=13, name=wg}, Sort{age=19, name=wa}, Sort{age=16, name=wb}]
排序后的结果：[Sort{age=12, name=wf}, Sort{age=13, name=wg}, Sort{age=16, name=wb}, Sort{age=18, name=ww}, Sort{age=19, name=wa}]