Mybatis with Spring Boot example

MyBatis is one of the most commonly used open-source frameworks for implementing SQL databases access in Java applications.

MyBatis is a SQL Mapping framework with support for custom SQL, stored procedures and advanced mappings. SpringBoot doesn’t provide official support for MyBatis integration, but the MyBatis community built a SpringBoot starter for MyBatis.

You can read about the SpringBoot MyBatis https://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/ and you can explore the source code on GitHub https://github.com/mybatis/mybatis-spring-boot.

In this quick tutorial, we’ll present how to integrate MyBatis with Spring and Spring Boot.

1. dependency needed for mybatis :

<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId><version>2.1.3</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>

2. Mapper using Annotation:

#mybatis using annotation and spring boot

MainClass:

@SpringBootApplication
@MapperScan(“com.example.demo.mapper”)
@MappedTypes({Students.class})
public class RoledemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(RoledemoApplication.class, args);
    }
}

**@MapperScan used to map directory in which you have mapper classes.

**@MappedTypes used to map modal classes.

ModalClass:

public class Student {
  private Integer studId;
  private String name;
  private String email;
  // setters and getters
}

MapperInterface:

@Mapper
public interface StudentMapper {
@Select(“select * from Students”)
List<Student> findAllStudents();
@Select(“select * from Students where studId=#{id}”)
Student findStudentById(Integer id);
@Insert(“insert into Students(name,email) values(name=#{name},email=#{email})”)
void insertStudent(Student student);
@Update(“update Students set name=#{student.name},email=#{student.email} where studId=#{id}”)
void updateStudent(Student student,int id);
@Delete(“delete from Students where studId=#{id}”)
void deleteStudent(Interger id);
}

ControllerClass:

@RestController
@RequestMapping(value = “/”, consumes = “application/json”, produces = “application/json”)
public class MainController{
  @Autowired
  StudentMapper studentMapper;
  @GetMapping(“/findAllStudents”)
  public List<Students> findAllStudents(){
    return studentMapper.findAllStudents();
  }
  @PostMapping(“/insertStudent”)
  public void insertStudent(@RequestBody Students students){
    studentMapper.insertStudent(student);
  }
  @PutMapping(“/updateStudent/{id}”)
  public void updateStudent(@RequestBody Students   students,@PathVariable(“id”) int id){
    studentMapper.updateStudent(student,id);
  }
  @DeleteMapping(“/deleteStudent/{id}”)
  public void deleteStudent(@PathVariable(“id”) int id){
    studentMapper.deleteStudent(id);
  }
}

3. Mapper using XML:

#mybatis using XML and spring boot

MainClass:

@SpringBootApplication
@MapperScan(“com.example.demo.mapper”)
public class RoledemoApplication {
  public static void main(String[] args) {
    SpringApplication.run(RoledemoApplication.class, args);
  }
}

ModalClass:

public class Student {
  private Integer studId;
  private String name;
  private String email;
  // setters and getters
}

MapperInterface:

@Mapper
public interface StudentMapper{
  List<Student> findAllStudents();
  Student findStudentById(Integer id);
  void insertStudent(Student student);
  void updateStudent(Student student,int id);
  void deleteStudent(Interger id);
}

ControllerClass:

@RestController
@RequestMapping(value = “/”, consumes = “application/json”, produces = “application/json”)
public class MainController{
  @Autowired
  StudentMapper studentMapper;
  @GetMapping(“/findAllStudents”)
  public List<Students> findAllStudents(){
    return studentMapper.findAllStudents();
  }
  @PostMapping(“/insertStudent”)
  public void insertStudent(@RequestBody Students students){
    studentMapper.insertStudent(student);
  }
  @PutMapping(“/updateStudent/{id}”)
  public void updateStudent(@RequestBody Students students,@PathVariable(“id”) int id){
    studentMapper.updateStudent(student,id);
  }
  @DeleteMapping(“/deleteStudent/{id}”)
  public void deleteStudent(@PathVariable(“id”) int id){
    studentMapper.deleteStudent(id);
  }
}

application.properties:

server.port = 8080
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/demo
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.testWhileIdle=true
spring.datasource.validationQuery=SELECT 1
mybatis.config-location=classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.type-aliases-package=com.example.demo.model

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <typeAlias alias="Integer" type="java.lang.Integer" />
        <typeAlias alias="Long" type="java.lang.Long" />
        <typeAlias alias="HashMap" type="java.util.HashMap" />
        <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" />
        <typeAlias alias="ArrayList" type="java.util.ArrayList" />
        <typeAlias alias="LinkedList" type="java.util.LinkedList" />
        <typeAlias type="com.example.demo.model.Students" alias="Students" />
    </typeAliases>
</configuration>

StudentsMapper.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.demo.mapper.StudentMapper">
    <resultMap id="StudentResultMap" type="Students">
        <id column="id" property="id" jdbcType="INTEGER"/>
        <result column="name" property="name" jdbcType="VARCHAR"/>
        <result column="email" property="email" jdbcType="VARCHAR"/>
    </resultMap>
    <sql id="Base_Column_List">
        id, name, email
    </sql>
    <select id="findAllStudents" resultMap="StudentResultMap">
        SELECT
        <include refid="Base_Column_List"/>
        FROM Students
    </select>
<insert id="insertStudent" parameterType="Students"   resultMap="StudentResultMap">
      INSERT INTO Students(name,email) VALUES(#{name},#{email})</insert>
<update id="updateStudent">
    UPDATE
    Students SET
    <if test="student.name!=null">name=#{student.name},</if>
    <if test="student.email!=null">email=#{student.email}</if>
    WHERE studId=#{id}
</update>
<delete id="deleteStudent" parameterType="int">
    DELETE FROM Students
    WHERE studId =#{id}
</delete>
</mapper>