springboot与mybatis 整合完整教程

项目总览结构

pom.xml

 <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>3.0.4</version>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

准备数据源

create table student
(
    id   bigint auto_increment comment '主键ID'
        primary key,
    name varchar(32) null comment '姓名',
    sex  int         null,
    age  int         null
);

添加数据库配置信息

# 配置Spring Boot应用的数据库源
spring:
  datasource:
    # 数据库连接URL，包含数据库的地址，端口，数据库名以及连接参数
    url: jdbc:mysql://192.168.1.53:3306/student_info?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    # 数据库用户名
    username: root
    # 数据库密码
    password: 1
    # 数据库驱动类名
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:
  # MyBatis的Mapper XML文件位置
  mapper-locations: classpath:mapper/*.xml
  # MyBatis的类型别名包，用于简化配置
  type-aliases-package: com.js.handlemybatis.dao

修改启动类

@SpringBootApplication
@MapperScan("com.jd.handlemybatisdemo.mapper")
public class HandleMybatisDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(HandleMybatisDemoApplication.class, args);
    }

}

dao包 创建Student.java

package com.js.handlemybatis.dao;

public class Student {
    private Long id;
    private String name;
    private Integer age;
    private Integer sex;

    public Student() {
    }

    public Student(String name, Integer age, Integer sex) {
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    public Student(Long id, String name, Integer age, Integer sex) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getSex() {
        return sex;
    }

    public void setSex(Integer sex) {
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", sex=" + sex +
                '}';
    }
}

mapper包 添加 StudentMapper.java

package com.js.handlemybatis.mapper;

import com.js.handlemybatis.dao.Student;


import java.util.List;


public interface StudentMapper {
    List<Student> selectAll();
}

resource/mapper文件夹下 添加StudentMapper.xml

<?xml version="1.0" encoding="utf-8" ?>
<!-- 遵循MyBatis 3.0的映射器(DTD Mapper)公共类型定义 -->
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 定义一个映射器，namespace为映射器的唯一标识符，通常对应一个具体的DAO接口 -->
<mapper namespace="com.js.handlemybatis.mapper.StudentMapper">
    <!-- 定义一个查询操作，id为操作的唯一标识符，resultMap指定结果集映射 -->
    <select id="selectAll" resultMap="BaseResultMap">
        <!-- SQL查询语句：选择学生表中的所有列 -->
        select *
        from student
    </select>
    <!-- 定义结果集映射，id为映射的唯一标识符，type指定映射到的Java类型 -->
    <resultMap id="BaseResultMap" type="com.js.handlemybatis.dao.Student">
        <!-- 映射学生表的id列到Student类的id属性，jdbcType指定对应的数据库类型 -->
        <id column="id" property="id" jdbcType="BIGINT"/>
        <!-- 映射学生表的name列到Student类的name属性，jdbcType指定对应的数据库类型 -->
        <result column="name" property="name" jdbcType="VARCHAR"/>
        <!-- 映射学生表的age列到Student类的age属性，javaType指定对应的Java类型 -->
        <result column="age" property="age" javaType="Integer"/>
        <!-- 映射学生表的sex列到Student类的sex属性，javaType指定对应的Java类型 -->
        <result column="sex" property="sex" javaType="Integer"/>
    </resultMap>
</mapper>

单元测试

 @Autowired
    private StudentMapper studentMapper;
    @Test
    void contextLoadsHandleSelectAll() {
        List<Student> students = studentMapper.selectAll();
        for (Student student : students) {
            System.out.println(student);

        }
    }

实战:实现学生信息管理模块

修改mapper接口

import com.js.handlemybatis.dao.Student;


import java.util.List;


public interface StudentMapper {
    List<Student> selectAll();
    Student selectOneById(Long id);
    int insert(Student student);
    int update(Student student);
    int delete(Long id);
}

修改mapper映射文件

<?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">
<!-- 定义一个Mapper，命名空间为com.js.handlemybatis.mapper.StudentMapper -->
<mapper namespace="com.js.handlemybatis.mapper.StudentMapper">
    <!-- 定义一个查询所有学生的SQL语句 -->
    <select id="selectAll" resultMap="BaseResultMap">
        select *
        from student
    </select>
    <!-- 定义一个根据ID查询单个学生的SQL语句 -->
    <select id="selectOneById" resultMap="BaseResultMap">
        select *
        from student
        where id = #{id}
    </select>
    <!-- 定义一个插入学生的SQL语句 -->
    <insert id="insert">
        insert into student(name, age, sex)
        values (#{name}, #{age}, #{sex})
    </insert>
    <!-- 定义一个更新学生的SQL语句 -->
    <update id="update">
        update student
        set name = #{name},
        age = #{age},
        sex = #{sex}
        where id = #{id}
    </update>
    <!-- 定义一个删除学生的SQL语句 -->
    <delete id="delete">
        delete from student
        where id = #{id}
    </delete>

    <!-- 定义一个结果映射，将查询结果映射到Student对象 -->
    <resultMap id="BaseResultMap" type="com.js.handlemybatis.dao.Student">
        <!-- 配置主键字段的映射 -->
        <id column="id" property="id" jdbcType="BIGINT"/>
        <!-- 配置其他字段的映射 -->
        <result column="name" property="name" jdbcType="VARCHAR"/>
        <result column="age" property="age" javaType="Integer"/>
        <result column="sex" property="sex" javaType="Integer"/>
    </resultMap>

</mapper>

单元测试

package com.js.handlemybatis;

import com.js.handlemybatis.dao.Student;
import com.js.handlemybatis.mapper.StudentMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

/**
 * HandleMyBatisApplicationTests类用于测试MyBatis的基本操作
 * 包括查询、插入、更新和删除操作
 */
@SpringBootTest
class HandleMyBatisApplicationTests {

    /**
     * contextLoads方法用于测试应用程序上下文是否正确加载
     * 这里没有执行任何业务逻辑，主要用于检查依赖注入和应用程序启动是否成功
     */
    @Test
    void contextLoads() {
    }

    /**
     * 注入StudentMapper接口的实例，用于执行数据库操作
     */
    @Autowired
    private StudentMapper studentMapper;

    /**
     * contextLoadsHandleSelectAll方法用于测试查询所有学生信息的功能
     * 它从数据库中选择所有学生，并打印出每个学生的信息
     */
    @Test
    void contextLoadsHandleSelectAll() {
        List<Student> students = studentMapper.selectAll();
        for (Student student : students) {
            System.out.println(student);
        }
    }

    /**
     * contextLoadsHandleInsert方法用于测试插入学生信息的功能
     * 它创建一个新的学生对象，插入到数据库中，并打印出所有学生的信息
     */
    @Test
    void contextLoadsHandleInsert() {
        Student student = new Student("lijun", 18, 1);
        studentMapper.insert(student);
        List<Student> students = studentMapper.selectAll();
        for (Student st : students) {
            System.out.println(st);
        }
    }

    /**
     * contextLoadsHandleUpdate方法用于测试更新学生信息的功能
     * 它根据ID选择一个学生，更新其信息，并打印出所有学生的信息
     */
    @Test
    void contextLoadsHandleUpdate() {
        Student student = studentMapper.selectOneById(4L);
        student.setName("lijunqiang");
        student.setAge(28);
        studentMapper.update(student);
        // 打印出所有数据
        List<Student> students = studentMapper.selectAll();
        for (Student st : students) {
            System.out.println(st);
        }
    }

    /**
     * contextLoadsHandleSelectOneById方法用于测试按ID查询学生信息的功能
     * 它根据指定的ID选择一个学生，并打印出该学生的信息
     */
    @Test
    void contextLoadsHandleSelectOneById() {
        Student student = studentMapper.selectOneById(2L);
        System.out.println(student);
    }

    /**
     * contextLoadsHandleDelete方法用于测试删除学生信息的功能
     * 它首先打印出所有学生的信息，然后根据指定ID删除一个学生，最后再次打印出所有学生的信息
     */
    @Test
    void contextLoadsHandleDelete() {
        List<Student> students = studentMapper.selectAll();
        for (Student st : students) {
            System.out.println(st);
        }
        studentMapper.delete(4L);
        for (Student st : students) {
            System.out.println(st);
        }
    }

}