// 实体类
public class Student {
    private int id;
    private String name;

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

    // getter和setter方法
}

// 数据访问对象接口
public interface StudentDao {
    List getAllStudents();
    Student getStudent(int id);
    void updateStudent(Student student);
    void deleteStudent(Student student);
}

// 数据访问对象实现
public class StudentDaoImpl implements StudentDao {
    private List students;

    public StudentDaoImpl() {
        students = new ArrayList<>();
        students.add(new Student(1, "张三"));
        students.add(new Student(2, "李四"));
    }

    @Override
    public List getAllStudents() {
        return students;
    }

    @Override
    public Student getStudent(int id) {
        return students.stream()
            .filter(student -> student.getId() == id)
            .findFirst()
            .orElse(null);
    }

    @Override
    public void updateStudent(Student student) {
        students.set(student.getId() - 1, student);
    }

    @Override
    public void deleteStudent(Student student) {
        students.remove(student.getId() - 1);
    }
}

// 使用示例
public class DaoPatternDemo {
    public static void main(String[] args) {
        StudentDao studentDao = new StudentDaoImpl();

        // 输出所有学生
        for(Student student : studentDao.getAllStudents()) {
            System.out.println("Student: [ID : " + student.getId() + ", Name : " + student.getName() + "]");
        }

        // 更新学生
        Student student = studentDao.getStudent(1);
        student.setName("王五");
        studentDao.updateStudent(student);

        // 获取更新后的学生
        student = studentDao.getStudent(1);
        System.out.println("Student: [ID : " + student.getId() + ", Name : " + student.getName() + "]");
    }
}