List实现排序

Posted 2022-08-15 aibaiyang

1、使用java.util.Comparator 创建一个比较器来进行排序

 

    public static void main(String[] args) 

        Student student1 = new Student (1L ,"by");
        Student student2 = new Student (2L ,"zs");
        Student student3 = new Student (3L ,"ls");

        List<Student> students = new ArrayList<>();
        students.add(student2);
        students.add(student3);
        students.add(student1);

        //1、原始数据输出
        // [Student(id=2, name=zs), Student(id=3, name=ls), Student(id=1, name=by)]
        System.out.println(students);

        //2、使用 Comparator.comparing 进行排序(根据id顺序进行排序)
        // 法一
        // [Student(id=1, name=by), Student(id=2, name=zs), Student(id=3, name=ls)]
        students.sort(Comparator.comparing(e -> e.getId()));
        System.out.println(students);

        // 法二
        // [Student(id=1, name=by), Student(id=2, name=zs), Student(id=3, name=ls)]
        students.sort(Comparator.comparing(Student::getId));
        System.out.println(students);

        //3、根据id倒序排序
        students.sort(Comparator.comparing(Student::getId).reversed());
        // [Student(id=3, name=ls), Student(id=2, name=zs), Student(id=1, name=by)]
        System.out.println(students);

    

 

 

参考：https://blog.csdn.net/rungong123/article/details/88421272