MyBatis adds the function to get the auto-incrementing primary key

Prepare

Database t_Student table

Student class

MyBatis adds the function to get the auto-incrementing primary key

interface

public interface StudentMapper {
    
    

    int inserStudent(Student student);

}

map file

<?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"><!--约束，约束不同xml中所写的标签也不同-->
<mapper namespace="com.xxx.mapper.StudentMapper"><!--接口-->

<!--    int inserStudent(Student student); -->
    <insert id="inserStudent" useGeneratedKeys="true" keyProperty="id">
        insert into t_student values(null,#{name},#{age},#{sex})
    </insert>


</mapper>

Description: useGeneratedKeys="true" sets the use of auto-incrementing primary keys. keyProperty="id", where id is the self-incrementing primary key, which is the id attribute in the Student class.

test

		StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
		//创建需要插入的对象
		Student st = new Student("小明",10,"男");

		//调用插入函数
        int i = mapper.inserStudent(st);

		//输出主键
        System.out.println(st.getId());

output result