Java实现根据某个字段对集合进行去重并手动选择被保留的对象

需求说明：

现有对象Student（id,name,age），并有List<Student> students集合，要求：对students集合中的对象按age去重，并保留id较大的那个对象。

Student

public class Student {
    private int id;
    private String name;
    private String age;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

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

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

实现代码：

public static void main(String[] args) {
        //获取集合
        List<Student> students = getStudentList();
        //输出当前集合
        System.out.println(students);
        //去重后的集合
        List<Student> newStudentList = new ArrayList<>();
        //去重字段和对象
        HashMap<String, Student> stuMap = new HashMap<>();
        //循环
        students.forEach(student -> {
            //出现age重复
            if (stuMap.containsKey(student.getAge())) {
                //老对象
                int oldId = stuMap.get(student.getAge()).getId();
                //新对象
                int currId = student.getId();
                //比较新老对象的Id
                if (oldId < currId) {
                    //如果新对象Id比较大，则保留新对象
                    stuMap.put(student.getAge(), student);
                }
            } else {
                //如果没有重复的直接添加
                stuMap.put(student.getAge(), student);
            }
        });
        //把数据转移到新集合里
        newStudentList.addAll(stuMap.values());
        System.out.println(newStudentList);
    }

    private static List<Student> getStudentList() {
        List<Student> students = new ArrayList<>();
        Student st1 = new Student();
        st1.setId(1);
        st1.setName("张三");
        st1.setAge("23");
        students.add(st1);

        Student st2 = new Student();
        st2.setId(2);
        st2.setName("李四");
        st2.setAge("24");
        students.add(st2);

        Student st3 = new Student();
        st3.setId(3);
        st3.setName("王五");
        st3.setAge("25");
        students.add(st3);

        Student st4 = new Student();
        st4.setId(4);
        st4.setName("赵六");
        st4.setAge("23");
        students.add(st4);
        return students;
    }