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研究生管理信息系统的源码解析与技术实现

本文通过对话形式,深入探讨研究生管理信息系统的核心功能、源码结构及技术实现方式。

小明:嘿,李老师,最近我在研究一个研究生管理系统,听说这个系统挺复杂的,您能给我讲讲它的源码结构吗?

李老师:当然可以。研究生管理系统通常是一个基于Web的多层架构应用,前端使用HTML、CSS和JavaScript,后端可能用Java或Python,数据库一般是MySQL或PostgreSQL。你对哪部分特别感兴趣?

小明:我对后端代码比较好奇,特别是Java相关的。您能给我举个例子吗?比如学生信息管理模块的源码是怎么写的?

李老师:好的,我们以学生信息管理为例。首先,我们需要一个实体类来表示学生信息。在Java中,这通常是一个POJO(Plain Old Java Object)类,包含基本属性如学号、姓名、性别、专业等。

public class Student {

private String studentId;

private String name;

private String gender;

private String major;

// 构造函数

public Student() {}

public Student(String studentId, String name, String gender, String major) {

this.studentId = studentId;

this.name = name;

this.gender = gender;

this.major = major;

}

// Getter 和 Setter 方法

public String getStudentId() {

return studentId;

}

public void setStudentId(String studentId) {

this.studentId = studentId;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getGender() {

return gender;

}

public void setGender(String gender) {

this.gender = gender;

}

public String getMajor() {

return major;

}

public void setMajor(String major) {

this.major = major;

}

}

小明:哇,原来如此!那这些数据是如何存储到数据库里的呢?是不是需要一个DAO层?

李老师:没错,DAO(Data Access Object)层负责与数据库交互。我们可以使用JDBC或者更高级的框架如Hibernate或MyBatis来简化数据库操作。

public interface StudentDao {

void addStudent(Student student);

Student getStudentById(String id);

List getAllStudents();

void updateStudent(Student student);

void deleteStudent(String id);

}

public class StudentDaoImpl implements StudentDao {

private Connection connection;

public StudentDaoImpl(Connection connection) {

this.connection = connection;

}

@Override

public void addStudent(Student student) {

String sql = "INSERT INTO students (student_id, name, gender, major) VALUES (?, ?, ?, ?)";

try (PreparedStatement stmt = connection.prepareStatement(sql)) {

stmt.setString(1, student.getStudentId());

stmt.setString(2, student.getName());

stmt.setString(3, student.getGender());

stmt.setString(4, student.getMajor());

stmt.executeUpdate();

} catch (SQLException e) {

e.printStackTrace();

}

}

@Override

public Student getStudentById(String id) {

String sql = "SELECT * FROM students WHERE student_id = ?";

try (PreparedStatement stmt = connection.prepareStatement(sql)) {

stmt.setString(1, id);

ResultSet rs = stmt.executeQuery();

if (rs.next()) {

Student student = new Student();

student.setStudentId(rs.getString("student_id"));

student.setName(rs.getString("name"));

student.setGender(rs.getString("gender"));

student.setMajor(rs.getString("major"));

return student;

}

} catch (SQLException e) {

e.printStackTrace();

}

return null;

}

@Override

public List getAllStudents() {

List students = new ArrayList<>();

String sql = "SELECT * FROM students";

try (Statement stmt = connection.createStatement();

ResultSet rs = stmt.executeQuery(sql)) {

while (rs.next()) {

Student student = new Student();

student.setStudentId(rs.getString("student_id"));

student.setName(rs.getString("name"));

student.setGender(rs.getString("gender"));

student.setMajor(rs.getString("major"));

students.add(student);

}

} catch (SQLException e) {

e.printStackTrace();

}

return students;

}

@Override

public void updateStudent(Student student) {

String sql = "UPDATE students SET name = ?, gender = ?, major = ? WHERE student_id = ?";

try (PreparedStatement stmt = connection.prepareStatement(sql)) {

stmt.setString(1, student.getName());

stmt.setString(2, student.getGender());

stmt.setString(3, student.getMajor());

stmt.setString(4, student.getStudentId());

stmt.executeUpdate();

} catch (SQLException e) {

e.printStackTrace();

}

}

@Override

public void deleteStudent(String id) {

String sql = "DELETE FROM students WHERE student_id = ?";

try (PreparedStatement stmt = connection.prepareStatement(sql)) {

stmt.setString(1, id);

stmt.executeUpdate();

} catch (SQLException e) {

e.printStackTrace();

}

}

}

小明:看来DAO层是连接数据库的关键部分。那业务逻辑层又是怎么处理的呢?

李老师:业务逻辑层通常由Service类来实现,它调用DAO方法完成具体的业务操作。例如,添加学生时,可能会先检查学号是否重复,再执行插入操作。

public class StudentService {

private StudentDao studentDao;

public StudentService(StudentDao studentDao) {

this.studentDao = studentDao;

}

public void addStudent(Student student) {

if (studentDao.getStudentById(student.getStudentId()) != null) {

throw new IllegalArgumentException("学号已存在");

}

studentDao.addStudent(student);

}

public Student getStudentById(String id) {

return studentDao.getStudentById(id);

}

public List getAllStudents() {

return studentDao.getAllStudents();

}

public void updateStudent(Student student) {

studentDao.updateStudent(student);

}

public void deleteStudent(String id) {

studentDao.deleteStudent(id);

}

}

小明:明白了!那前端是怎么和后端进行交互的呢?是不是用Servlet或者Spring MVC?

李老师:没错,通常我们会使用Spring MVC框架来构建Web应用。前端通过HTTP请求调用Controller,Controller调用Service,Service再调用DAO,最后返回结果给前端。

@Controller

@RequestMapping("/students")

public class StudentController {

private StudentService studentService;

public StudentController(StudentService studentService) {

this.studentService = studentService;

}

@GetMapping("/")

public String listStudents(Model model) {

model.addAttribute("students", studentService.getAllStudents());

return "student/list";

}

@GetMapping("/add")

public String showAddForm(Model model) {

model.addAttribute("student", new Student());

return "student/add";

}

@PostMapping("/add")

public String addStudent(@ModelAttribute("student") Student student) {

studentService.addStudent(student);

return "redirect:/students/";

}

@GetMapping("/edit/{id}")

public String showEditForm(@PathVariable("id") String id, Model model) {

Student student = studentService.getStudentById(id);

model.addAttribute("student", student);

return "student/edit";

}

@PostMapping("/edit/{id}")

public String updateStudent(@PathVariable("id") String id, @ModelAttribute("student") Student student) {

student.setStudentId(id);

studentService.updateStudent(student);

return "redirect:/students/";

}

@GetMapping("/delete/{id}")

public String deleteStudent(@PathVariable("id") String id) {

研究生系统

studentService.deleteStudent(id);

return "redirect:/students/";

}

}

小明:这个Controller看起来很规范!那数据库的设计又是什么样的呢?

李老师:数据库表设计是整个系统的基础。以学生表为例,通常会有学号、姓名、性别、专业、入学日期等字段。

CREATE TABLE students (

student_id VARCHAR(20) PRIMARY KEY,

name VARCHAR(100),

gender VARCHAR(10),

major VARCHAR(100),

enrollment_date DATE

);

小明:这样设计确实很清晰。那如果我要扩展功能,比如添加课程管理模块,应该怎么处理呢?

李老师:扩展功能通常需要新增实体类、DAO接口、Service类以及Controller,并修改数据库结构。比如,课程表可能包括课程编号、名称、学分、教师等信息。

CREATE TABLE courses (

course_id VARCHAR(20) PRIMARY KEY,

course_name VARCHAR(100),

credit INT,

teacher VARCHAR(100)

);

小明:明白了!看来这个系统的可扩展性还是很强的。

李老师:没错,良好的架构设计和模块化编程让系统更容易维护和升级。如果你有兴趣,还可以学习Spring Boot、Spring Security等更高级的技术。

小明:谢谢您,李老师!今天收获很大,我回去好好研究一下这些代码。

李老师:不客气,有问题随时问我。祝你学习顺利!

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