用java实现一个简单的电通宿舍管理系统。 定义抽象类Student，根据需要设计属性和行为。定义派生类，即三个专业的学生：DianxinStu、DiankeStu、TongxinStu。必须应用方法的覆盖。 宿舍楼有6层，每层20个房间，每个房间最多可以住学生4人。男生和女生要分在不同层，同专业的学生优先安排在同一宿舍。 主要功能有：新生来了为其分配宿舍；学生毕业了离开宿舍；根据房间号、性别、所属专业查询宿舍（包括宿舍为空的情况）；根据学生要求调换宿舍；其他功能可自行拓展，比如统计等。

以下是一个简单的电通宿舍管理系统的Java实现：

abstract class Student {
    protected String name;
    protected String gender;
    protected String major;
    protected int roomNumber;
    protected int floorNumber;

    public Student(String name, String gender, String major) {
        this.name = name;
        this.gender = gender;
        this.major = major;
    }

    public void setRoomNumber(int roomNumber) {
        this.roomNumber = roomNumber;
    }

    public void setFloorNumber(int floorNumber) {
        this.floorNumber = floorNumber;
    }

    public abstract void displayInfo();
}

class DianxinStu extends Student {
    public DianxinStu(String name, String gender) {
        super(name, gender, "Dianxin");
    }

    @Override
    public void displayInfo() {
        System.out.println("Name: " + name + ", Gender: " + gender + ", Major: " + major + ", Floor Number: " + floorNumber + ", Room Number: " + roomNumber);
    }
}

class DiankeStu extends Student {
    public DiankeStu(String name, String gender) {
        super(name, gender, "Dianke");
    }

    @Override
    public void displayInfo() {
        System.out.println("Name: " + name + ", Gender: " + gender + ", Major: " + major + ", Floor Number: " + floorNumber + ", Room Number: " + roomNumber);
    }
}

class TongxinStu extends Student {
    public TongxinStu(String name, String gender) {
        super(name, gender, "Tongxin");
    }

    @Override
    public void displayInfo() {
        System.out.println("Name: " + name + ", Gender: " + gender + ", Major: " + major + ", Floor Number: " + floorNumber + ", Room Number: " + roomNumber);
    }
}

class Dormitory {
    private Student[][] rooms;
    private int[] maleFloors;
    private int[] femaleFloors;

    public Dormitory() {
        rooms = new Student[6][20];
        maleFloors = new int[]{1, 2, 3};
        femaleFloors = new int[]{4, 5, 6};
    }

    public boolean allocateRoom(Student student) {
        int floorNumber;
        if (student.gender.equals("Male")) {
            floorNumber = getAvailableFloor(maleFloors, student.major);
        } else {
            floorNumber = getAvailableFloor(femaleFloors, student.major);
        }
        if (floorNumber == -1) {
            return false;
        }
        int roomNumber = getAvailableRoom(floorNumber);
        if (roomNumber == -1) {
            return false;
        }
        student.setFloorNumber(floorNumber);
        student.setRoomNumber(roomNumber);
        rooms[floorNumber - 1][roomNumber - 1] = student;
        return true;
    }

    private int getAvailableFloor(int[] floors, String major) {
        for (int floorNumber : floors) {
            if (isFloorAvailable(floorNumber, major)) {
                return floorNumber;
            }
        }
        return -1;
    }

    private boolean isFloorAvailable(int floorNumber, String major) {
        for (int i = 0; i < 20; i++) {
            if (rooms[floorNumber - 1][i] == null) {
                continue;
            }
            if (rooms[floorNumber - 1][i].major.equals(major)) {
                return false;
            }
        }
        return true;
    }

    private int getAvailableRoom(int floorNumber) {
        for (int i = 0; i < 20; i++) {
            if (rooms[floorNumber - 1][i] == null) {
                return i + 1;
            }
        }
        return -1;
    }

    public boolean removeStudent(int floorNumber, int roomNumber) {
        if (rooms[floorNumber - 1][roomNumber - 1] == null) {
            return false;
        }
        rooms[floorNumber - 1][roomNumber - 1] = null;
        return true;
    }

    public Student getStudent(int floorNumber, int roomNumber, String gender, String major) {
        if (rooms[floorNumber - 1][roomNumber - 1] == null) {
            return null;
        }
        Student student = rooms[floorNumber - 1][roomNumber - 1];
        if (!student.gender.equals(gender) || !student.major.equals(major)) {
            return null;
        }
        return student;
    }

    public boolean changeRoom(int floorNumber, int roomNumber, String gender, String major) {
        Student student = getStudent(floorNumber, roomNumber, gender, major);
        if (student == null) {
            return false;
        }
        if (!allocateRoom(student)) {
            return false;
        }
        removeStudent(floorNumber, roomNumber);
        return true;
    }

    public void displayStudents() {
        for (int i = 0; i < 6; i++) {
            System.out.println("Floor " + (i + 1) + ":");
            for (int j = 0; j < 20; j++) {
                if (rooms[i][j] != null) {
                    rooms[i][j].displayInfo();
                } else {
                    System.out.println("Room " + (j + 1) + ": Empty");
                }
            }
        }
    }
}

public class DormitoryManagementSystem {
    public static void main(String[] args) {
        Dormitory dormitory = new Dormitory();

        // Allocate rooms for students
        dormitory.allocateRoom(new DianxinStu("John", "Male"));
        dormitory.allocateRoom(new DiankeStu("Lucy", "Female"));
        dormitory.allocateRoom(new TongxinStu("Tom", "Male"));
        dormitory.allocateRoom(new DianxinStu("Alice", "Female"));
        dormitory.allocateRoom(new DiankeStu("Bob", "Male"));
        dormitory.allocateRoom(new TongxinStu("Kate", "Female"));

        // Display all students
        dormitory.displayStudents();

        // Remove a student
        dormitory.removeStudent(1, 1);

        // Display all students again
        dormitory.displayStudents();

        // Change a student's room
        dormitory.changeRoom(2, 1, "Male", "Dianxin");

        // Display all students again
        dormitory.displayStudents();
    }
}

上述代码定义了一个抽象类`Student`，以及三个具体的子类`DianxinStu`、`DiankeStu`和`TongxinStu`。它还定义了一个`Dormitory`类来管理宿舍楼。`Dormitory`类包含了分配房间、删除学生、查询学生、调换房间以及显示所有学生等方法。`DormitoryManagementSystem`类是一个简单的测试程序，它创建了一个`Dormitory`对象并分配了一些学生到宿舍楼中，同时也测试了其他的方法。