Finally, I finished the month-long DDL battle and picked up my old love again.

In the next few days, I’ll go through the process: Mybatis -> Spring -> Spring MVC!

1. XML Configuration and Basic CRUD with XML

Maven XML Dependencies
<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.12</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.19</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.5</version>
    </dependency>
</dependencies>
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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="password"/>
            </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <mapper resource="UserMapper.xml"/>
    </mappers>
</configuration>
Mapper 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="xyz.aiinirii.mapper.UserMapper">
    <select id="findAll" resultType="User">
        SELECT * FROM user
    </select>
</mapper>

2. Key Concepts

  • SqlSessionFactory: Creates SqlSession instances
  • SqlSession: Represents the connection to the database
  • Mapper: Interface that defines database operations

3. CRUD Operations

// Select
List<User> users = sqlSession.selectList("findAll");

// Insert
sqlSession.insert("insertUser", user);

// Update
sqlSession.update("updateUser", user);

// Delete
sqlSession.delete("deleteUser", id);

Summary

Mybatis is a lightweight ORM framework that maps SQL statements to Java methods, providing flexibility and control over database operations.