用Java学生信息管理系统

学生信息管理系统是一个典型的 CRUD 应用，即增加(Create)、查询(Retrieve)、修改(Update)和删除(Delete)。下面是一个使用Java语言实现学生信息管理系统的简单示例。

1. 数据库设计

首先需要设计数据库表结构，这里我们设计两张表：学生表和课程表。

学生表：

| 列名 | 数据类型 | 说明 |
| --------- | -------- | ---------- |
| id | int | 学生编号 |
| name | varchar | 学生姓名 |
| gender | varchar | 学生性别 |
| birthday | date | 学生生日 |
| address | varchar | 学生住址 |
| telephone | varchar | 学生电话号码 |

课程表：

| 列名 | 数据类型 | 说明 |
| -------- | -------- | -------- |
| id | int | 课程编号 |
| name | varchar | 课程名称 |
| credit | int | 课程学分 |
| teacher | varchar | 授课教师 |
| location | varchar | 授课地点 |

2. Java代码实现

接下来，我们使用Java语言编写学生信息管理系统的代码。我们使用MySQL作为数据库，使用JDBC连接数据库。

2.1. 建立数据库连接

在Java中，可以使用JDBC连接MySQL数据库。需要导入MySQL的JDBC驱动包，然后使用以下代码建立数据库连接：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DatabaseConnection {
    private static final String URL = "jdbc:mysql://localhost:3306/student";
    private static final String USERNAME = "root";
    private static final String PASSWORD = "root";

    public static Connection getConnection() {
        Connection conn = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }
}

2.2. 学生信息管理

定义一个 Student 类，用于保存学生信息。然后定义一个 StudentDao 类，实现对学生信息的增删改查操作。

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class StudentDao {
    // 查询所有学生信息
    public List<Student> findAll() {
        List<Student> students = new ArrayList<>();
        Connection conn = DatabaseConnection.getConnection();
        String sql = "SELECT * FROM student";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                Student student = new Student();
                student.setId(rs.getInt("id"));
                student.setName(rs.getString("name"));
                student.setGender(rs.getString("gender"));
                student.setBirthday(rs.getDate("birthday"));
                student.setAddress(rs.getString("address"));
                student.setTelephone(rs.getString("telephone"));
                students.add(student);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return students;
    }

    // 根据学生编号查询学生信息
    public Student findById(int id) {
        Student student = null;
        Connection conn = DatabaseConnection.getConnection();
        String sql = "SELECT * FROM student WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            ResultSet rs = pstmt.executeQuery();
            if (rs.next()) {
                student = new Student();
                student.setId(rs.getInt("id"));
                student.setName(rs.getString("name"));
                student.setGender(rs.getString("gender"));
                student.setBirthday(rs.getDate("birthday"));
                student.setAddress(rs.getString("address"));
                student.setTelephone(rs.getString("telephone"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return student;
    }

    // 添加学生信息
    public void add(Student student) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "INSERT INTO student(name, gender, birthday, address, telephone) VALUES (?, ?, ?, ?, ?)";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, student.getName());
            pstmt.setString(2, student.getGender());
            pstmt.setDate(3, student.getBirthday());
            pstmt.setString(4, student.getAddress());
            pstmt.setString(5, student.getTelephone());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 更新学生信息
    public void update(Student student) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "UPDATE student SET name=?, gender=?, birthday=?, address=?, telephone=? WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, student.getName());
            pstmt.setString(2, student.getGender());
            pstmt.setDate(3, student.getBirthday());
            pstmt.setString(4, student.getAddress());
            pstmt.setString(5, student.getTelephone());
            pstmt.setInt(6, student.getId());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 删除学生信息
    public void delete(int id) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "DELETE FROM student WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

2.3. 课程信息管理

定义一个 Course 类，用于保存课程信息。然后定义一个 CourseDao 类，实现对课程信息的增删改查操作。

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class CourseDao {
    // 查询所有课程信息
    public List<Course> findAll() {
        List<Course> courses = new ArrayList<>();
        Connection conn = DatabaseConnection.getConnection();
        String sql = "SELECT * FROM course";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            ResultSet rs = pstmt.executeQuery();
            while (rs.next()) {
                Course course = new Course();
                course.setId(rs.getInt("id"));
                course.setName(rs.getString("name"));
                course.setCredit(rs.getInt("credit"));
                course.setTeacher(rs.getString("teacher"));
                course.setLocation(rs.getString("location"));
                courses.add(course);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return courses;
    }

    // 根据课程编号查询课程信息
    public Course findById(int id) {
        Course course = null;
        Connection conn = DatabaseConnection.getConnection();
        String sql = "SELECT * FROM course WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            ResultSet rs = pstmt.executeQuery();
            if (rs.next()) {
                course = new Course();
                course.setId(rs.getInt("id"));
                course.setName(rs.getString("name"));
                course.setCredit(rs.getInt("credit"));
                course.setTeacher(rs.getString("teacher"));
                course.setLocation(rs.getString("location"));
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return course;
    }

    // 添加课程信息
    public void add(Course course) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "INSERT INTO course(name, credit, teacher, location) VALUES (?, ?, ?, ?)";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, course.getName());
            pstmt.setInt(2, course.getCredit());
            pstmt.setString(3, course.getTeacher());
            pstmt.setString(4, course.getLocation());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 更新课程信息
    public void update(Course course) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "UPDATE course SET name=?, credit=?, teacher=?, location=? WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, course.getName());
            pstmt.setInt(2, course.getCredit());
            pstmt.setString(3, course.getTeacher());
            pstmt.setString(4, course.getLocation());
            pstmt.setInt(5, course.getId());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    // 删除课程信息
    public void delete(int id) {
        Connection conn = DatabaseConnection.getConnection();
        String sql = "DELETE FROM course WHERE id=?";
        try {
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

3. 测试

在测试代码中，我们可以使用 StudentDao 和 CourseDao 类的方法操作数据库。

import java.util.List;

public class Test {
    public static void main(String[] args) {
        // 查询所有学生信息
        StudentDao studentDao = new StudentDao();
        List<Student> students = studentDao.findAll();
        for (Student student : students) {
            System.out.println(student);
        }

        // 查询所有课程信息
        CourseDao courseDao = new CourseDao();
        List<Course> courses = courseDao.findAll();
        for (Course course : courses) {
            System.out.println(course);
        }

        // 添加学生信息
        Student student = new Student();
        student.setName("张三");
        student.setGender("男");
        student.setBirthday(Date.valueOf("2000-01-01"));
        student.setAddress("北京市");
        student.setTelephone("123456789");
        studentDao.add(student);

        // 更新学生信息
        student = studentDao.findById(1);
        student.setName("李四");
        studentDao.update(student);

        // 删除学生信息
        studentDao.delete(1);
    }
}

以上就是一个简单的使用Java语言实现学生信息管理系统的示例。在实际开发中，可以根据需求进行扩展和优化。