http://www.javacodegeeks.com/2012/11/mybatis-tutorial-crud-operations-and-mapping-relationships-part-1.html
CRUD Operations
MyBatis is an SQL Mapper tool which greatly simplifies the database programing when compared to using JDBC directly.
Step1: Create a Maven project and configure MyBatis dependencies.
<project xmlns='http://maven.apache.org/POM/4.0.0'
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>com.sivalabs</groupId>
<artifactId>mybatis-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging> <name>mybatis-demo</name>
<url>http://maven.apache.org</url> <properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties> <build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<encoding>${project.build.sourceEncoding}</encoding>
</configuration>
</plugin>
</plugins>
</build> <dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.10</version>
<scope>test</scope>
</dependency> <dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.1.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.21</version>
<scope>runtime</scope>
</dependency>
</dependencies>
</project>
Step#2: Create the table USER and a Java domain Object User as follows:
CREATE TABLE user (
user_id int(10) unsigned NOT NULL auto_increment,
email_id varchar(45) NOT NULL,
password varchar(45) NOT NULL,
first_name varchar(45) NOT NULL,
last_name varchar(45) default NULL,
PRIMARY KEY (user_id),
UNIQUE KEY Index_2_email_uniq (email_id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
package com.sivalabs.mybatisdemo.domain;
public class User
{
private Integer userId;
private String emailId;
private String password;
private String firstName;
private String lastName; @Override
public String toString() {
return 'User [userId=' + userId + ', emailId=' + emailId
+ ', password=' + password + ', firstName=' + firstName
+ ', lastName=' + lastName + ']';
}
//setters and getters
}
Step#3: Create MyBatis configuration files.
a) Create jdbc.properties file in src/main/resources folder
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis-demo
jdbc.username=root
jdbc.password=admin
b) Create mybatis-config.xml file in src/main/resources folder
<?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>
<properties resource='jdbc.properties'/>
<typeAliases>
<typeAlias type='com.sivalabs.mybatisdemo.domain.User' alias='User'></typeAlias>
</typeAliases>
<environments default='development'>
<environment id='development'>
<transactionManager type='JDBC'/>
<dataSource type='POOLED'>
<property name='driver' value='${jdbc.driverClassName}'/>
<property name='url' value='${jdbc.url}'/>
<property name='username' value='${jdbc.username}'/>
<property name='password' value='${jdbc.password}'/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource='com/sivalabs/mybatisdemo/mappers/UserMapper.xml'/>
</mappers>
</configuration>
Step#4: Create an interface UserMapper.java in src/main/java folder in com.sivalabs.mybatisdemo.mappers package.
package com.sivalabs.mybatisdemo.mappers; import java.util.List;
import com.sivalabs.mybatisdemo.domain.User; public interface UserMapper
{ public void insertUser(User user); public User getUserById(Integer userId); public List<User> getAllUsers(); public void updateUser(User user); public void deleteUser(Integer userId); }
Step#5: Create UserMapper.xml file in src/main/resources folder in com.sivalabs.mybatisdemo.mappers package.
<?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.sivalabs.mybatisdemo.mappers.UserMapper'> <select id='getUserById' parameterType='int' resultType='com.sivalabs.mybatisdemo.domain.User'>
SELECT
user_id as userId,
email_id as emailId ,
password,
first_name as firstName,
last_name as lastName
FROM USER
WHERE USER_ID = #{userId}
</select>
<!-- Instead of referencing Fully Qualified Class Names we can register Aliases in mybatis-config.xml and use Alias names. -->
<resultMap type='User' id='UserResult'>
<id property='userId' column='user_id'/>
<result property='emailId' column='email_id'/>
<result property='password' column='password'/>
<result property='firstName' column='first_name'/>
<result property='lastName' column='last_name'/>
</resultMap> <select id='getAllUsers' resultMap='UserResult'>
SELECT * FROM USER
</select> <insert id='insertUser' parameterType='User' useGeneratedKeys='true' keyProperty='userId'>
INSERT INTO USER(email_id, password, first_name, last_name)
VALUES(#{emailId}, #{password}, #{firstName}, #{lastName})
</insert> <update id='updateUser' parameterType='User'>
UPDATE USER
SET
PASSWORD= #{password},
FIRST_NAME = #{firstName},
LAST_NAME = #{lastName}
WHERE USER_ID = #{userId}
</update> <delete id='deleteUser' parameterType='int'>
DELETE FROM USER WHERE USER_ID = #{userId}
</delete> </mapper>
Step#6: Create MyBatisUtil.java to instantiate SqlSessionFactory.
package com.sivalabs.mybatisdemo.service; import java.io.IOException;
import java.io.Reader;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MyBatisUtil
{
private static SqlSessionFactory factory; private MyBatisUtil() {
} static
{
Reader reader = null;
try {
reader = Resources.getResourceAsReader('mybatis-config.xml');
} catch (IOException e) {
throw new RuntimeException(e.getMessage());
}
factory = new SqlSessionFactoryBuilder().build(reader);
} public static SqlSessionFactory getSqlSessionFactory()
{
return factory;
}
}
Step#7: Create UserService.java in src/main/java folder.
package com.sivalabs.mybatisdemo.service; import java.util.List;
import org.apache.ibatis.session.SqlSession;
import com.sivalabs.mybatisdemo.domain.User;
import com.sivalabs.mybatisdemo.mappers.UserMapper; public class UserService
{ public void insertUser(User user) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.insertUser(user);
sqlSession.commit();
}finally{
sqlSession.close();
}
} public User getUserById(Integer userId) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
return userMapper.getUserById(userId);
}finally{
sqlSession.close();
}
} public List<User> getAllUsers() {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
return userMapper.getAllUsers();
}finally{
sqlSession.close();
}
} public void updateUser(User user) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.updateUser(user);
sqlSession.commit();
}finally{
sqlSession.close();
} } public void deleteUser(Integer userId) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.deleteUser(userId);
sqlSession.commit();
}finally{
sqlSession.close();
} } }
Step#8: Create a JUnit Test class to test UserService methods.
package com.sivalabs.mybatisdemo; import java.util.List; import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test; import com.sivalabs.mybatisdemo.domain.User;
import com.sivalabs.mybatisdemo.service.UserService; public class UserServiceTest
{
private static UserService userService; @BeforeClass
public static void setup()
{
userService = new UserService();
} @AfterClass
public static void teardown()
{
userService = null;
} @Test
public void testGetUserById()
{
User user = userService.getUserById(1);
Assert.assertNotNull(user);
System.out.println(user);
} @Test
public void testGetAllUsers()
{
List<User> users = userService.getAllUsers();
Assert.assertNotNull(users);
for (User user : users)
{
System.out.println(user);
} } @Test
public void testInsertUser()
{
User user = new User();
user.setEmailId('test_email_'+System.currentTimeMillis()+'@gmail.com');
user.setPassword('secret');
user.setFirstName('TestFirstName');
user.setLastName('TestLastName'); userService.insertUser(user);
Assert.assertTrue(user.getUserId() != 0);
User createdUser = userService.getUserById(user.getUserId());
Assert.assertNotNull(createdUser);
Assert.assertEquals(user.getEmailId(), createdUser.getEmailId());
Assert.assertEquals(user.getPassword(), createdUser.getPassword());
Assert.assertEquals(user.getFirstName(), createdUser.getFirstName());
Assert.assertEquals(user.getLastName(), createdUser.getLastName()); } @Test
public void testUpdateUser()
{
long timestamp = System.currentTimeMillis();
User user = userService.getUserById(2);
user.setFirstName('TestFirstName'+timestamp);
user.setLastName('TestLastName'+timestamp);
userService.updateUser(user);
User updatedUser = userService.getUserById(2);
Assert.assertEquals(user.getFirstName(), updatedUser.getFirstName());
Assert.assertEquals(user.getLastName(), updatedUser.getLastName());
} @Test
public void testDeleteUser()
{
User user = userService.getUserById(4);
userService.deleteUser(user.getUserId());
User deletedUser = userService.getUserById(4);
Assert.assertNull(deletedUser); }
}
Now, I will explain how to perform CRUD operations using MyBatis Annotation support without need of Queries configuration in XML mapper files.
Step#1: Create a table BLOG and a java domain Object Blog.
CREATE TABLE blog (
blog_id int(10) unsigned NOT NULL auto_increment,
blog_name varchar(45) NOT NULL,
created_on datetime NOT NULL,
PRIMARY KEY (blog_id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
package com.sivalabs.mybatisdemo.domain;
import java.util.Date;
public class Blog {
private Integer blogId;
private String blogName;
private Date createdOn;
@Override
public String toString() {
return 'Blog [blogId=' + blogId + ', blogName=' + blogName
+ ', createdOn=' + createdOn + ']';
}
//Seeters and getters
}
Step#2: Create UserMapper.java interface with SQL queries in Annotations.
package com.sivalabs.mybatisdemo.mappers; import java.util.List; import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update; import com.sivalabs.mybatisdemo.domain.Blog; public interface BlogMapper
{
@Insert('INSERT INTO BLOG(BLOG_NAME, CREATED_ON) VALUES(#{blogName}, #{createdOn})')
@Options(useGeneratedKeys=true, keyProperty='blogId')
public void insertBlog(Blog blog); @Select('SELECT BLOG_ID AS blogId, BLOG_NAME as blogName, CREATED_ON as createdOn FROM BLOG WHERE BLOG_ID=#{blogId}')
public Blog getBlogById(Integer blogId); @Select('SELECT * FROM BLOG ')
@Results({
@Result(id=true, property='blogId', column='BLOG_ID'),
@Result(property='blogName', column='BLOG_NAME'),
@Result(property='createdOn', column='CREATED_ON')
})
public List<Blog> getAllBlogs(); @Update('UPDATE BLOG SET BLOG_NAME=#{blogName}, CREATED_ON=#{createdOn} WHERE BLOG_ID=#{blogId}')
public void updateBlog(Blog blog); @Delete('DELETE FROM BLOG WHERE BLOG_ID=#{blogId}')
public void deleteBlog(Integer blogId); }
Step#3: Configure BlogMapper in 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>
<properties resource='jdbc.properties'/>
<environments default='development'>
<environment id='development'>
<transactionManager type='JDBC'/>
<dataSource type='POOLED'>
<!-- <property name='driver' value='com.mysql.jdbc.Driver'/>
<property name='url' value='jdbc:mysql://localhost:3306/mybatis-demo'/>
<property name='username' value='root'/>
<property name='password' value='admin'/> -->
<property name='driver' value='${jdbc.driverClassName}'/>
<property name='url' value='${jdbc.url}'/>
<property name='username' value='${jdbc.username}'/>
<property name='password' value='${jdbc.password}'/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper class='com.sivalabs.mybatisdemo.mappers.BlogMapper'/>
</mappers>
</configuration>
Step#4: Create BlogService.java
package com.sivalabs.mybatisdemo.service; import java.util.List; import org.apache.ibatis.session.SqlSession; import com.sivalabs.mybatisdemo.domain.Blog;
import com.sivalabs.mybatisdemo.mappers.BlogMapper; public class BlogService
{ public void insertBlog(Blog blog) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
BlogMapper blogMapper = sqlSession.getMapper(BlogMapper.class);
blogMapper.insertBlog(blog);
sqlSession.commit();
}finally{
sqlSession.close();
}
} public Blog getBlogById(Integer blogId) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
BlogMapper blogMapper = sqlSession.getMapper(BlogMapper.class);
return blogMapper.getBlogById(blogId);
}finally{
sqlSession.close();
}
} public List<Blog> getAllBlogs() {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
BlogMapper blogMapper = sqlSession.getMapper(BlogMapper.class);
return blogMapper.getAllBlogs();
}finally{
sqlSession.close();
}
} public void updateBlog(Blog blog) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
BlogMapper blogMapper = sqlSession.getMapper(BlogMapper.class);
blogMapper.updateBlog(blog);
sqlSession.commit();
}finally{
sqlSession.close();
}
} public void deleteBlog(Integer blogId) {
SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession();
try{
BlogMapper blogMapper = sqlSession.getMapper(BlogMapper.class);
blogMapper.deleteBlog(blogId);
sqlSession.commit();
}finally{
sqlSession.close();
} } }
Step#5: Create JUnit Test for BlogService methods
package com.sivalabs.mybatisdemo; import java.util.Date;
import java.util.List; import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test; import com.sivalabs.mybatisdemo.domain.Blog;
import com.sivalabs.mybatisdemo.service.BlogService; public class BlogServiceTest
{
private static BlogService blogService; @BeforeClass
public static void setup()
{
blogService = new BlogService();
} @AfterClass
public static void teardown()
{
blogService = null;
} @Test
public void testGetBlogById()
{
Blog blog = blogService.getBlogById(1);
Assert.assertNotNull(blog);
System.out.println(blog);
} @Test
public void testGetAllBlogs()
{
List<Blog> blogs = blogService.getAllBlogs();
Assert.assertNotNull(blogs);
for (Blog blog : blogs)
{
System.out.println(blog);
} } @Test
public void testInsertBlog()
{
Blog blog = new Blog();
blog.setBlogName('test_blog_'+System.currentTimeMillis());
blog.setCreatedOn(new Date()); blogService.insertBlog(blog);
Assert.assertTrue(blog.getBlogId() != 0);
Blog createdBlog = blogService.getBlogById(blog.getBlogId());
Assert.assertNotNull(createdBlog);
Assert.assertEquals(blog.getBlogName(), createdBlog.getBlogName()); } @Test
public void testUpdateBlog()
{
long timestamp = System.currentTimeMillis();
Blog blog = blogService.getBlogById(2);
blog.setBlogName('TestBlogName'+timestamp);
blogService.updateBlog(blog);
Blog updatedBlog = blogService.getBlogById(2);
Assert.assertEquals(blog.getBlogName(), updatedBlog.getBlogName());
} @Test
public void testDeleteBlog()
{
Blog blog = blogService.getBlogById(4);
blogService.deleteBlog(blog.getBlogId());
Blog deletedBlog = blogService.getBlogById(4);
Assert.assertNull(deletedBlog);
}
}