mybatis Tutorial => Getting started with mybatis

Remarks

This section provides an overview of what mybatis is, and why a developer might want to use it.

It should also mention any large subjects within mybatis, and link out to the related topics. Since the Documentation for mybatis is new, you may need to create initial versions of those related topics.

Hello world using Spring Boot and Maven

Add the necessary dependencies to the project POM (mybatis , and mybatis-spring ):

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>x.x.x</version>
</dependency>
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>1.3.1-SNAPSHOT</version>
</dependency>

A SqlSessionFactory is needed to create mybatis sessions. Spring allows one to be quickly configured using SqlSessionFactoryBean . Simply define a SqlSessionFactoryBean bean, and give the reference to the DataSource bean:

@Bean
public SqlSessionFactoryBean sqlSessionFactoryBean(DataSource dataSource) {
    SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
    sqlSessionFactoryBean.setDataSource(dataSource);
    return sqlSessionFactoryBean;
}

Define a mybatis mapper. The mapper is a java interface that will hold SQL queries and translate method calls into JDBC queries. If a default Spring Boot HSQLDB database is being used, this following query can be created. (There are tables involved; it simply returns a string built using a user-provided parameter).

public interface HelloWorldMapper {

    @Select("VALUES ('Hello ' || #{origin})")
    String getString(@Param("origin") String origin);

}

Register existing mappers so Mybatis and Spring can know about them. Add @MapperScan to the spring java configuration with the name of the "root" package containing the mapper interfaces. This annotation will auto-register the interfaces as spring beans, which can be easily injected anywhere in the application.

    @Autowired
    private HelloWorldMapper helloWorldMapper;

    // invoking the mapper method
    helloWorldMapper.getString("World");

Here's the complete Spring configuration class, with a test invocation of the query:

package com.example;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.TypeExcludeFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.FilterType;

import javax.annotation.PostConstruct;
import javax.sql.DataSource;
import java.lang.annotation.*;

@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan
@MapperScan("com.example")
public class DemoApplication {

    @Autowired
    private HelloWorldMapper helloWorldMapper;

    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource);
        return (SqlSessionFactory) sqlSessionFactoryBean.getObject();
    }

    @PostConstruct
    public void init() {
        System.out.println(helloWorldMapper.getString("World"));
    }

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

}

Spring Boot- Jersey-Mybatis-MySql REST Maven Project step by step

Requirement for Local development
1) MySQL server(I am Using XAMPP for MySQL server)
2) For Test API You can use Postman(optional)
3) Before run application,make sure MySQL server is running, properly prepare your application.properties file(DB_Name, Username,Password).

1.Add following dependency,parent into your POM.xml file

   <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.0.RELEASE</version>
    </parent>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jersey</artifactId>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-multipart</artifactId>
            <version>2.18</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

        <dependency>
            <groupId>commons-validator</groupId>
            <artifactId>commons-validator</artifactId>
            <version>1.5.0</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-sample-annotation</artifactId>
            <version>1.1.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.1</version>
        </dependency>



        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

My Project Structure Should be This

src-->
     main-->
          java
          |--->com-->controller
          |              |--UserController.java
          |              |--CORSResponseFilter.java
          |           entity
          |              |--User.java
          |           mapper
          |              |--UserMapper.java
          |           JerseyConfig.java
          |           SampleMapperApplication.java
          |           
          resources
                 |-->application.properties

2.Create an Entity Class named User in src\main\java\com\entity\User.java

package com.entity;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;

import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Size;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    private int id;

    @Size(min = 2, max =50)
    @Pattern(regexp = "[A-Za-z. ]*", message = "First name requires valid character")
    private String firstname;

    @Size(min = 2, max =50)
    @Pattern(regexp = "[A-Za-z. ]*", message = "First name requires valid character")
    private String lastname;


    //@Column(unique = true)
    @NotNull(message =  "Email requires valid value")
    @NotEmpty(message = "Email requires non empty value")
    @Email(message =    "Email requires valid format")
    private String email;

    @Size(min = 2, max =50)
    @Pattern(regexp = "[A-Za-z.0-9 ]*", message = "First name requires valid character")
    private String password;

    @Pattern(regexp = "[0-9.\\-+ ]*", message = "Phone requires valid alphanumaric characters")
    private String phone;

    private int age;
    /*setter getter method here*/


    
}

3.Create A interface named UserMapper.java into src\main\java\com\mapper\UserMapper.java

package com.mapper;


import com.entity.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

@Mapper
public interface UserMapper {
    @Insert("INSERT INTO USER ( firstname,lastname, email,password,age ,phone ) VALUES ( #{user.firstname}, #{user.lastname},#{user.email},#{user.password}, #{user.age},#{user.phone})")
    Integer insertUser(@Param("user") User user) throws Exception;

    @Select("select * from user where email = #{email}")
    User findByEmail(@Param("email") String email);

    @Select("select * from user where email = #{email} AND id!=#{id}")
    User findByEmailNotUser(@Param("email") String email,@Param("id") Integer id);

    @Select("select * from user where id = #{id}")
    User findById(@Param("id") Integer id);

    @Select("select * from user where email = #{email} AND password = #{password}")
    User login(@Param("email") String email,@Param("password") String password);


    @Select("select * from user")
    List<User> getUsers();

    @Update("UPDATE USER SET firstname = #{user.firstname},lastname = #{user.lastname},email = #{user.email},phone = #{user.phone},age = #{user.age} WHERE id = #{user.id}")
    Integer updateUser(@Param("user") User user) throws Exception;

    @Delete("DELETE from user where id = #{id}")
    Integer deleteById(@Param("id") Integer id);



}

4.Create Two class UserController.java into src\main\java\com\controller\UserController.java

package com.controller;

import com.entity.User;
import com.mapper.UserMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;


import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Set;


@Controller
@Path("/users")
public class UserController {
    static final Logger logger = LoggerFactory.getLogger(UserController.class);
    private static Validator validator = Validation.buildDefaultValidatorFactory().getValidator();

    @Autowired
    private UserMapper userMapper;

    @POST
    @Consumes("application/json")
    @Produces("application/json")
    public Response create(User user) {
        LinkedHashMap<Object, Object> serviceResponse = new LinkedHashMap<Object, Object>();
        logger.info("Starting to create a user");

        try {
            Set<ConstraintViolation<User>> validateErrors = validator.validate(user);
            if (validateErrors.isEmpty()) {
                if (userMapper.findByEmail(user.getEmail()) != null) {
                    serviceResponse.put("duplicate_Email", "user already exist");
                } else {
                    Integer createPerson = userMapper.insertUser(user);

                    if (createPerson != 1) {
                        serviceResponse.put("created", "unable to create user");
                    } else {
                        logger.info("Successfully created User.");
                        serviceResponse.put("created_msg", "Successfully created User");
                    }
                }
                return Response.status(Response.Status.CREATED).entity(serviceResponse).build();
            } else {
                logger.info("Failed to create a user due to field validation errors.");
                logger.debug("Unable to create a user due to validation errors using {}", user);
                //JSONObject jsonObj = new JSONObject(validateErrors.toString());
                serviceResponse.put("error", validateErrors.toString());
                return Response.status(400).entity(serviceResponse).build();


            }
        } catch (Exception e) {
            logger.debug("<< create()");
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(serviceResponse).build();
        }
    }


    @GET
    @Produces("application/json")
    public Response getUsers() {

        LinkedHashMap<String, Object> response = new LinkedHashMap<String, Object>();
        try {
            List<User> listUsers = userMapper.getUsers();
            if (listUsers == null) {
                response.put("users", Collections.emptyMap());
            } else {
                response.put("total", listUsers.size());
                response.put("users", listUsers);
            }
            return Response.status(Response.Status.OK).entity(listUsers).build();
        } catch (Exception ex) {

            response.put("user", "Not Found");
            return Response.status(Response.Status.BAD_REQUEST).entity(response).build();
        }
    }

    @PUT
    @Path("/{id}")
    @Produces("application/json")
    public Response updateUser(@PathParam("id") Integer id, User user) {
        //String personJson = gson.toJson(user);
        //logger.debug(">> create({})", personJson);
        //LinkedHashMap<Object, Object> apiResponse = new LinkedHashMap<>();
        LinkedHashMap<Object, Object> serviceResponse = new LinkedHashMap<Object, Object>();
        logger.info("Starting to create a person");

        try {
            Set<ConstraintViolation<User>> validateErrors = validator.validate(user);
            if (validateErrors.isEmpty()) {
                if (userMapper.findById(id) == null) {
                    serviceResponse.put("msg", "User Not Found");
                } else {
                    if (userMapper.findByEmailNotUser(user.getEmail(), user.getId()) != null) {
                        serviceResponse.put("duplicate_Email", "user already exist");
                    } else {
                        int updateUser = userMapper.updateUser(user);
                        if (updateUser == 0) {
                            serviceResponse.put("created", "unable to update User");
                        } else {
                            logger.info("Successfully update user.");
                            serviceResponse.put("update", user);
                        }
                    }
                }
                return Response.status(Response.Status.OK).entity(user).build();
            } else {
                logger.info("Failed to update a user due to field validation errors.");
                // logger.debug("Unable to update a user due to validation errors using {}", personJson);
                serviceResponse.put("error", validateErrors.toString());

                return Response.status(400).entity(serviceResponse).build();
            }
        } catch (Exception e) {
            logger.debug("<< create()");
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(serviceResponse).build();
        }
    }

    @GET
    @Path("/{id}")
    @Produces("application/json")
    public Response getPerson(@PathParam("id") int userId) {

        LinkedHashMap<String, Object> response = new LinkedHashMap<String, Object>();

        try {
            User user = userMapper.findById(userId);

            if (user == null) {
                response.put("User", Collections.emptyMap());
            } else {
                response.put("user", user);
            }
            return Response.status(Response.Status.OK).entity(user).build();
        } catch (Exception ex) {

            response.put("user", "Not Found");
            return Response.status(Response.Status.BAD_REQUEST).entity(response).build();
        }
    }

    @DELETE
    @Path("/{id}")
    @Consumes("application/json")
    @Produces("application/json")
    public Response deleteUser(@PathParam("id") int userId) {

        //LinkedHashMap<Object, Object> apiResponse = new LinkedHashMap<>();
        LinkedHashMap<Object, Object> serviceResponse = new LinkedHashMap<Object, Object>();
        logger.info("Starting to delete a user");

        try {
            int deletePerson = userMapper.deleteById(userId);
            if (deletePerson == 0) {
                serviceResponse.put("delete", "unable delete user");
            } else {
                logger.info("Successfully delete user.");
                serviceResponse.put("delete", "Successfully delete user.");
            }
            return Response.status(Response.Status.OK).entity(serviceResponse).build();

        } catch (Exception e) {

            logger.debug("<< create()");
            return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(serviceResponse).build();
        }
    }

}

5.Create CORSResponseFilter.java class into src\main\java\com\controller\CORSResponseFilter.java

package com.controller;

import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerResponseContext;
import javax.ws.rs.container.ContainerResponseFilter;
import javax.ws.rs.core.MultivaluedMap;
import java.io.IOException;


public class CORSResponseFilter implements ContainerResponseFilter {
    public void filter(ContainerRequestContext requestContext, ContainerResponseContext responseContext)
            throws IOException {

        MultivaluedMap<String, Object> headers = responseContext.getHeaders();

        headers.add("Access-Control-Allow-Origin", "*");
        //headers.add("Access-Control-Allow-Origin", "http://abcd.org"); //allows CORS requests only coming from abcd.org
        headers.add("Access-Control-Allow-Methods", "GET, POST, DELETE, PUT");
        headers.add("Access-Control-Allow-Headers", "X-Requested-With, Content-Type");
    }
}

6.Register your Configuration Class into JerseyConfig class src\main\java\com\JerseyConfig.java

package com;

import com.controller.CORSResponseFilter;
import com.controller.UserController;
import org.glassfish.jersey.server.ResourceConfig;
import org.springframework.context.annotation.Configuration;

import javax.ws.rs.ApplicationPath;


@Configuration
@ApplicationPath("/api")
public class JerseyConfig extends ResourceConfig {
    public JerseyConfig() {
        register(CORSResponseFilter.class);
        register(UserController.class);
       

    }

}

7. Create your application class named SampleMapperApplication into src\main\java\com\SampleMapperApplication.java

package com;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;


@SpringBootApplication
public class SampleMapperApplication implements CommandLineRunner {
    
    public static void main(String[] args) {
        SpringApplication.run(SampleMapperApplication.class, args);
        
    }

    
}

8. Prepare your application.properties file src\main\resources\application.properties

# localhost:3306 will be replace your DB server url if you want. I am using MySql local DB server
spring.datasource.url = jdbc:mysql://localhost:3306/YOUR_DB_NAME
db.driver=com.mysql.jdbc.Driver
#if you want update, just replace create with update
spring.jpa.hibernate.ddl-auto=create 
#If you want to change default port(8080) number, Comment out below line code 
#server.port = 8090

# Username and password
spring.datasource.username = YOUR_DB_USER_NAME
spring.datasource.password =YOUR_DB_USER_PASSWORD

For Testing user REST API

  List of User(GET) ---->http://localhost:8080/api/users
  Create User(POST) ---->http://localhost:8080/api/users
  Get User(GET)    ----->http://localhost:8080/api/users/1
  Update User(PUT) ----->http://localhost:8080/api/users/1
  Delete User(Delete)--->http://localhost:8080/api/users/1

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Got any mybatis Question?