Java排序的那些事之sort方法的使用详解

import java.util.Arrays;

public class SortTest01 {
    public static void main(String[] args) {
        int[] array = {2, 4, 8, 9, 78, 1, 3, 66}; // 整型数组
        Arrays.sort(array); // 升序排序
        for (int i : array) {
            System.out.print(i + " ");
        }
    }
}

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class SortTest02 {
    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>(); // 定义一个链表
        // 降序放入list
        for (int i = 10; i >= 0; --i) {
            list.add(i);
        }
        Collections.sort(list); // 升序排序
        for (var i : list) {
            System.out.print(i + " ");
        }
    }
}

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

public class SortTest03 {
    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>(); // 定义一个链表
        // 升序放入list
        for (int i = 0; i <= 10; ++i) {
            list.add(i);
        }
        Collections.sort(list, new MyCompare()); // 降序排序
        for (var i : list) {
            System.out.print(i + " ");
        }
    }
}
class MyCompare implements Comparator<Integer> {
    // 制定排序规则：降序
    @Override
    public int compare(Integer o1, Integer o2) {
        return o2 - o1;
    }
}

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

public class SortTest04 {
    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>(); // 定义一个链表
        // 升序放入list
        for (int i = 0; i <= 10; ++i) {
            list.add(i);
        }
        // 匿名内部类降序排序
        Collections.sort(list, new Comparator<Integer>() {
            @Override
            public int compare(Integer o1, Integer o2) {
                return o2 - o1;
            }
        });
        for (var i : list) {
            System.out.print(i + " ");
        }
    }
}

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class SortTest04 {
    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>(); // 定义一个链表
        // 升序放入list
        for (int i = 0; i <= 10; ++i) {
            list.add(i);
        }
        // Lambda表达式降序排序
        Collections.sort(list, (o1, o2) -> o2 - o1);
        for (var i : list) {
            System.out.print(i + " ");
        }
    }
}

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

public class SortTest05 {
    public static void main(String[] args) {
        List<Student> list = new LinkedList<>(); // 创建一个链表
        list.add(new Student(18, "202101", "张三"));
        list.add(new Student(28, "202180", "李四"));
        list.add(new Student(11, "202135", "王五"));
        list.add(new Student(18, "202169", "赵六"));
        list.add(new Student(11, "202122", "小七"));
        list.add(new Student(48, "202156", "碧萝"));
        // 排序前
        for (var i : list) {
            System.out.println("name:" + i.getName() + " age:" + i.getAge() + " ID:" + i.getID());
        }
        Collections.sort(list, new StuCompare()); // 自定义排序规则排序
        // 排序后
        System.out.println("=======================");
        for (var i : list) {
            System.out.println("name:" + i.getName() + " age:" + i.getAge() + " ID:" + i.getID());
        }
    }
}
// 学生类
class Student {
    private int age; // 年龄
    private String ID; // 学号
    private String name; // 姓名

    public Student() {
    }
    public Student(int age, String ID, String name) {
        this.age = age;
        this.ID = ID;
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getID() {
        return ID;
    }
    public void setID(String ID) {
        this.ID = ID;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}
// 学生排序类
class StuCompare implements Comparator<Student> {
    // 升序
    @Override
    public int compare(Student o1, Student o2) {
        int flag;
        // 先通过年龄排序
        flag = o1.getAge() - o2.getAge();
        // 如果年龄相同，则通过学号比较排序
        if (flag == 0) {
            flag = o1.getID().compareTo(o2.getID());
        }
        return flag;
    }
}