Java Generate/Merge Files(3)DAO Layer of Mybatis

Java Generate/Merge Files(3)DAO Layer of Mybatis

I used Ibatis for years, I used hibernate for years as well. But my friend recommend mybatis to me sometime ago. So this time I tried to use Mybatis for my ORM tool.

pom.xml provide us the dependencies
<!-- myIbatis -->
<dependency>
     <groupId>org.mybatis</groupId>
     <artifactId>mybatis</artifactId>
     <version>3.4.2</version>
</dependency>
<dependency>
     <groupId>org.mybatis</groupId>
     <artifactId>mybatis-spring</artifactId>
     <version>1.3.1</version>
</dependency>
<dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>6.0.6</version>
</dependency>
<dependency>
     <groupId>c3p0</groupId>
     <artifactId>c3p0</artifactId>
     <version>0.9.1.2</version>
</dependency>

Database related XML configuration and properties
<!-- DATABASE -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
     <property name="dataSource" ref="dataSource" />
     <property name="configLocation" value="classpath:mybatis-config.xml" />
     <property name="mapperLocations" value="classpath:mapper/*.xml" />
</bean>

<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
     <property name="dataSource" ref="dataSource" />
</bean>

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
     <!-- access -->
     <property name="driverClass" value="${db.driver}" />
     <property name="jdbcUrl" value="${db.url}" />
     <property name="user" value="${db.user}" />
     <property name="password" value="${db.password}" />
     <!-- pool sizing -->
     <property name="initialPoolSize" value="2" />
     <property name="minPoolSize" value="2" />
     <property name="maxPoolSize" value="20" />
     <property name="acquireIncrement" value="3" />
     <property name="maxStatements" value="0" />
     <!-- retries -->
     <property name="acquireRetryAttempts" value="30" />
     <property name="acquireRetryDelay" value="1000" /> <!-- 1s -->
     <property name="breakAfterAcquireFailure" value="false" />
     <!-- refreshing connections -->
     <property name="maxIdleTime" value="180" /> <!-- 3min -->
     <property name="maxConnectionAge" value="10" /> <!-- 1h -->
     <!-- timeouts and testing -->
     <property name="checkoutTimeout" value="5000" /> <!-- 5s -->
     <property name="idleConnectionTestPeriod" value="60" /> <!-- 60 -->
     <property name="testConnectionOnCheckout" value="true" />
     <property name="preferredTestQuery" value="SELECT 1" />
     <property name="testConnectionOnCheckin" value="true" />
</bean>

<bean id="sourceDAO" class="org.mybatis.spring.mapper.MapperFactoryBean" >
        <property name="mapperInterface" value="com.j2c.feeds2g.daos.SourceDAO" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>
<bean id="campaignDAO" class="org.mybatis.spring.mapper.MapperFactoryBean" >
        <property name="mapperInterface" value="com.j2c.feeds2g.daos.CampaignDAO" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

mybatis-config.xml file
<?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>
<!-- namespace -->
<!--
<typeAliases>
<typeAlias alias="Source" type="com.j2c.feeds2g.models.Source" />
</typeAliases>
-->
<typeAliases>
  <package name="com.j2c.feeds2g.models"/>
</typeAliases>
</configuration>


Disable other logging
com.mchange.v2.log.MLog=com.mchange.v2.log.FallbackMLog
com.mchange.v2.log.FallbackMLog.DEFAULT_CUTOFF_LEVEL=WARNING

Configuration logging
db.driver=com.mysql.cj.jdbc.Driver
db.url=jdbc:mysql://jobs-stage.xxxxx.amazonaws.com:3306/jobs
db.user=xxxxxx
db.password=xxxxxxx

Actually, I only defined a XML mapping which will map our java objects to our database column. And I defined a java interface which will give use the handler to call the DAO layer.
<?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.j2c.feeds2g.daos.SourceDAO">
<resultMap type="com.j2c.feeds2g.models.Source" id="Source">
        <id column="id" property="id"  />
        <result property="status" column="status"/>
    </resultMap>

    <select id="loadActiveSources" resultMap="Source">
        SELECT id, status FROM job_sources
    </select>

    <!--
    <insert id="insertUser" parameterType="User">
        INSERT INTO users (firstName, lastName, email)
        VALUES (#{firstName}, #{lastName}, #{email})
    </insert>

    <update id="updateUser" parameterType="User">
        UPDATE users SET
            firstName = #{firstName},
            lastName = #{lastName},
            email = #{email}
        WHERE ID = #{id}
    </update>
    -->
</mapper>

package com.j2c.feeds2g.daos;

import java.util.List;

import com.j2c.feeds2g.models.Source;

public interface SourceDAO {

    public List<Source> loadActiveSources();

}

Then we only need to unit tests the class and ENV
package com.j2c.feeds2g.daos;

import java.util.List;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.j2c.feeds2g.models.Source;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:test-context.xml" })
public class SourceDAOTest {

    @Autowired
    @Qualifier("sourceDAO")
    private SourceDAO sourceDAO;

    @Test
    public void dummy() {
        Assert.assertTrue(true);
    }

    @Test
    public void loadActiveSources(){
        List<Source> results = sourceDAO.loadActiveSources();
        Assert.assertNotNull(results);
    }

}

References:
http://limingnihao.iteye.com/blog/781671

http://www.mybatis.org/spring/

https://blog.lanyonm.org/articles/2014/04/21/spring-4-mybatis-java-config.html

old sample
https://github.com/LTWangxi/spring-mb/tree/master/kdxr/src/main/resources/conf

c3p0 pool
https://gist.github.com/chrissom/2351568
alibaba pool
https://github.com/alibaba/druid