java web 学生管理系统代码

由于 Java Web 学生管理系统实现的复杂性和涉及到的技术栈的多样性，这里无法提供完整的代码。但是，我们可以提供一个简单的示例代码，以供参考。

以下是一个基于 SpringBoot、MyBatis、MySQL 的学生管理系统的示例代码：

1. Student 实体类：

public class Student {
    private int id;
    private String name;
    private int age;
    // 省略 getter 和 setter 方法
}

2. StudentMapper 接口：

@Mapper
public interface StudentMapper {
    List<Student> listStudents();
    Student getStudentById(int id);
    int addStudent(Student student);
    int updateStudent(Student student);
    int deleteStudent(int id);
}

3. StudentMapper.xml 映射文件：

<mapper namespace="com.example.mapper.StudentMapper">
    <resultMap id="studentMap" type="com.example.entity.Student">
        <id column="id" property="id"/>
        <result column="name" property="name"/>
        <result column="age" property="age"/>
    </resultMap>
    <select id="listStudents" resultMap="studentMap">
        select * from student
    </select>
    <select id="getStudentById" parameterType="int" resultMap="studentMap">
        select * from student where id=#{id}
    </select>
    <insert id="addStudent" parameterType="com.example.entity.Student">
        insert into student(name, age) values(#{name}, #{age})
    </insert>
    <update id="updateStudent" parameterType="com.example.entity.Student">
        update student set name=#{name}, age=#{age} where id=#{id}
    </update>
    <delete id="deleteStudent" parameterType="int">
        delete from student where id=#{id}
    </delete>
</mapper>

4. StudentService 接口：

public interface StudentService {
    List<Student> listStudents();
    Student getStudentById(int id);
    int addStudent(Student student);
    int updateStudent(Student student);
    int deleteStudent(int id);
}

5. StudentServiceImpl 实现类：

@Service
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    @Override
    public List<Student> listStudents() {
        return studentMapper.listStudents();
    }

    @Override
    public Student getStudentById(int id) {
        return studentMapper.getStudentById(id);
    }

    @Override
    public int addStudent(Student student) {
        return studentMapper.addStudent(student);
    }

    @Override
    public int updateStudent(Student student) {
        return studentMapper.updateStudent(student);
    }

    @Override
    public int deleteStudent(int id) {
        return studentMapper.deleteStudent(id);
    }
}

6. StudentController 控制器：

@RestController
@RequestMapping("/students")
public class StudentController {

    @Autowired
    private StudentService studentService;

    @GetMapping("")
    public List<Student> listStudents() {
        return studentService.listStudents();
    }

    @GetMapping("/{id}")
    public Student getStudentById(@PathVariable int id) {
        return studentService.getStudentById(id);
    }

    @PostMapping("")
    public int addStudent(@RequestBody Student student) {
        return studentService.addStudent(student);
    }

    @PutMapping("/{id}")
    public int updateStudent(@PathVariable int id, @RequestBody Student student) {
        student.setId(id);
        return studentService.updateStudent(student);
    }

    @DeleteMapping("/{id}")
    public int deleteStudent(@PathVariable int id) {
        return studentService.deleteStudent(id);
    }
}

以上示例代码中，我们使用了 SpringBoot 框架、MyBatis 数据库访问框架和 MySQL 数据库。通过 Student 实体类、StudentMapper 接口和 StudentMapper.xml 映射文件，实现了对学生信息的增删改查操作。通过 StudentService 接口和 StudentServiceImpl 实现类，提供了业务逻辑的处理。通过 StudentController 控制器，实现了 RESTful 风格的 API 接口，方便进行前端的调用。

注意：以上示例代码中的包名、类名、方法名等仅供参考，具体实现时需要根据自己的实际情况进行修改。