在数据库ssm中建立一张学生 表student,该表有如下字段: id, name, stuid, age; 利用mybatis知识，完成数据库表的增删改操作。数据库的创建语句(可以复制到word文档中)， 核心java代码文件即可。

以下是数据库表的创建语句：

CREATE TABLE `student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) NOT NULL,
`stuid` varchar(20) NOT NULL,
`age` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

以下是核心java代码文件：

1. Student.java

public class Student {
private int id;
private String name;
private String stuid;
private int age;

// getter and setter methods
}

2. StudentMapper.java

public interface StudentMapper {
// 添加学生
public void addStudent(Student student);

// 删除学生
public void deleteStudent(int id);

// 更新学生信息
public void updateStudent(Student student);

// 查询学生信息
public Student getStudentById(int id);
}

3. StudentMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mapper.StudentMapper">
<insert id="addStudent" parameterType="com.example.entity.Student">
INSERT INTO student(name, stuid, age) VALUES(#{name}, #{stuid}, #{age})
</insert>

<delete id="deleteStudent" parameterType="int">
DELETE FROM student WHERE id=#{id}
</delete>

<update id="updateStudent" parameterType="com.example.entity.Student">
UPDATE student SET name=#{name}, stuid=#{stuid}, age=#{age} WHERE id=#{id}
</update>

<select id="getStudentById" parameterType="int" resultType="com.example.entity.Student">
SELECT * FROM student WHERE id=#{id}
</select>
</mapper>