MyBatis Tutorial: Part-2: CRUD operations Using Annotations

In this post I will explain how to perform CRUD operations using MyBatis Annotation support without need of Queries configuration in XML mapper files.


MyBatis Tutorial: Part1 - CRUD Operations
MyBatis Tutorial: Part-2: CRUD operations Using Annotations
MyBatis Tutorial: Part 3 - Mapping Relationships
MyBatis Tutorial : Part4 - Spring Integration

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);
 }
}