将遍历出来的对象升序排列

Student s1 = new Student(14,"张三");
Student s2 = new Student(12,"王五");
Student s3 = new Student(16,"李四");
Student s4 = new Student(11,"lucy");

List<Student> stus = new ArrayList<Student>();
stus.add(s1);
stus.add(s2);
stus.add(s3);
stus.add(s4);

Collections.sort(stus,new Student());

for (Student stu : stus){
    System.out.println(stu.name + "," + stu.age);
}

Student类

class Student implements Comparator<Student>{
    int age;
    String name;

    public Student() {
    }

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

    @Override
    public int compare(Student o1, Student o2) {//根据年龄升序排列对象
        if (o1.age> o2.age){
            return 1;
        }else if(o1.age<o2.age){
            return -1;
        }else{
            return 0;
        }
    }
}