集成Mybatis

集成Mybatis到项目的步骤

初始化Mybatis的SqlSessionFactory，需要根据配置文件中mysql的相关参数来配置，参考MyBatisSqlSession代码；
添加mybatis-config.xml文件，配置mybatis的参数，包含DataSource的配置；
实现应用自身的DataSourceFactory，参考HikariDataSourceFactory代码;
实现DAOFactoryImpl来获取每个表对应的DAO对象，参考DAOFactoryImpl。

内部机制：

Mybatis从conf文件中获取到mysql的配置，并通过mybatis-config.xml文件将配置传给DataSource。

MyBatisSqlSession的实现

package co.yhy.api.persistence;

import co.yhy.common.ServiceConfig;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.io.Reader;
import java.util.Properties;

public class MyBatisSqlSession {
    private static final Logger LOGGER = LoggerFactory.getLogger(MyBatisSqlSession.class);
    private volatile static MyBatisSqlSession instance;
    private volatile boolean myBatisInitStatus = false;
    private SqlSessionFactory factory;

    private MyBatisSqlSession() {
    }

    public static MyBatisSqlSession getInstance() {
        if (instance == null) {
            synchronized (MyBatisSqlSession.class) {
                if (instance == null) {
                    instance = new MyBatisSqlSession();
                }
            }
        }
        return instance;
    }

    public boolean getMyBatisInitStatus() {
        return this.myBatisInitStatus;
    }

    public boolean init(ServiceConfig config) {
        try {
            Properties properties = new Properties();
            properties.setProperty(DAOFactory.CONF_DRIVER_CLASSNAME, config.getConfig(DAOFactory.CONF_DRIVER_CLASSNAME, "com.mysql.cj.jdbc.Driver"));
            properties.setProperty(DAOFactory.CONF_JDBC_URL, config.getConfig(DAOFactory.CONF_JDBC_URL, ""));
            properties.setProperty(DAOFactory.CONF_USERNAME, config.getConfig(DAOFactory.CONF_USERNAME, ""));
            properties.setProperty(DAOFactory.CONF_PASSWORD, config.getConfig(DAOFactory.CONF_PASSWORD, ""));
            properties.setProperty(DAOFactory.CONF_MAX_POOLSIZE, config.getConfig(DAOFactory.CONF_MAX_POOLSIZE, "10"));
            properties.setProperty(DAOFactory.CONF_AUTO_COMMIT, config.getConfig(DAOFactory.CONF_AUTO_COMMIT, "false"));
            properties.setProperty(DAOFactory.CONF_CACHE_PREPARESTATEMENT, config.getConfig(DAOFactory.CONF_CACHE_PREPARESTATEMENT, "true"));
            properties.setProperty(DAOFactory.CONF_PREPARESTATEMENT_CACHE_SIZE, config.getConfig(DAOFactory.CONF_PREPARESTATEMENT_CACHE_SIZE, "300"));
            properties.setProperty(DAOFactory.CONF_PREPARESTATEMENT_CACHE_LIMIT, config.getConfig(DAOFactory.CONF_PREPARESTATEMENT_CACHE_LIMIT, "2048"));
            properties.setProperty(DAOFactory.CONF_LEAK_DETECTION_THRESHOLD, config.getConfig(DAOFactory.CONF_LEAK_DETECTION_THRESHOLD, "0"));
            properties.setProperty(DAOFactory.CONF_MAXLIFETIME, config.getConfig(DAOFactory.CONF_MAXLIFETIME, "300000"));
            properties.setProperty(DAOFactory.CONF_CONNECTION_TIMEOUT, config.getConfig(DAOFactory.CONF_CONNECTION_TIMEOUT, "10000"));

            try (Reader reader = Resources.getResourceAsReader("mybatis-config.xml")) {
                factory = new SqlSessionFactoryBuilder().build(reader, properties);
                myBatisInitStatus = true;
                LOGGER.info("mybatis init success.");
            } catch (IOException e) {
                LOGGER.error("load mybatis-config.xml failed, {}", e.getMessage());
            }
        } catch (Exception e) {
            LOGGER.error("MyBatisSqlSession init failed ", e);
        }
        return myBatisInitStatus;
    }

    public SqlSessionFactory getSqlSessionFactory() {
        return factory;
    }

}

mybatis-config.xml文件的配置

<?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>
    <settings>
        <setting name="autoMappingUnknownColumnBehavior" value="WARNING"/>
        <!--设置超时时间，它决定驱动等待数据库响应的秒数。-->
        <setting name="defaultStatementTimeout" value="25"/>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <typeAliases>
        <typeAlias type='co.yhy.api.persistence.HikariDataSourceFactory' alias='HikariDataSourceFactory'/>
        <typeAlias type='co.yhy.common.pojo.Device' alias='Device'/>
        <typeAlias type='co.yhy.common.pojo.AppInfo' alias='AppInfo'/>
        <typeAlias type='co.yhy.api.persistence.resultMap.DataResult' alias='DataResult'/>
        <typeAlias type='co.yhy.api.persistence.resultMap.HistoryResult' alias='HistoryResult'/>
         </typeAliases>

    <typeHandlers>
        <typeHandler jdbcType="BLOB" javaType="byte[]" handler="org.apache.ibatis.type.BlobTypeHandler"/>
    </typeHandlers>

    <environments default='development'>
        <environment id='development'>
            <transactionManager type='JDBC'/>
            <dataSource type='HikariDataSourceFactory'>
                <property name="data_source.driverClassName" value="${data_source.driverClassName}"/>
                <property name="data_source.jdbc_url" value="${data_source.jdbc_url}"/>
                <property name="data_source.username" value="${data_source.username}"/>
                <property name="data_source.password" value="${data_source.password}"/>
                <property name="data_source.maximumPoolSize" value="${data_source.maximumPoolSize}"/>
                <property name="data_source.autoCommit" value="${data_source.autoCommit}"/>
                <property name="data_source.cachePrepStmts" value="${data_source.cachePrepStmts}"/>
                <property name="data_source.prepStmtCacheSize" value="${data_source.prepStmtCacheSize}"/>
                <property name="data_source.prepStmtCacheSqlLimit" value="${data_source.prepStmtCacheSqlLimit}"/>
                <property name="data_source.leakDetectionThreshold" value="${data_source.leakDetectionThreshold}"/>
                <property name="data_source.connectionTimeout" value="${data_source.connectionTimeout}"/>
                <property name="data_source.maxLifetime" value="${data_source.maxLifetime}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource='co/yhy/api/mappers/HistoryMapper.xml'/>
        <mapper resource='co/yhy/api/mappers/ConfigMapper.xml'/>
    </mappers>
</configuration

HikariDataSourceFactory的实现

package co.yhy.api.persistence;


import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import org.apache.ibatis.datasource.DataSourceFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.sql.DataSource;
import java.util.Properties;

public class HikariDataSourceFactory implements DataSourceFactory {

    private Properties properties;
    private static final Logger LOGGER = LoggerFactory.getLogger(HikariDataSourceFactory.class);

    @Override
    public void setProperties(Properties props) {
        this.properties = props;
    }

    @Override
    public DataSource getDataSource() {
        try {
            HikariConfig hikariConfig = new HikariConfig();
            hikariConfig.setJdbcUrl(properties.getProperty(DAOFactory.CONF_JDBC_URL, ""));
            hikariConfig.setUsername(properties.getProperty(DAOFactory.CONF_USERNAME, ""));
            hikariConfig.setPassword(properties.getProperty(DAOFactory.CONF_PASSWORD, ""));
            hikariConfig.setMaximumPoolSize(Integer.parseInt(properties.getProperty(DAOFactory.CONF_MAX_POOLSIZE, "10")));
            hikariConfig.setAutoCommit(Boolean.valueOf(properties.getProperty(DAOFactory.CONF_AUTO_COMMIT, "false")
            ));

            hikariConfig.setLeakDetectionThreshold(Long.parseLong(properties.getProperty(DAOFactory.CONF_LEAK_DETECTION_THRESHOLD, "0")));
            hikariConfig.setMaxLifetime(Long.parseLong(properties.getProperty(DAOFactory.CONF_MAXLIFETIME, "300000")));
            hikariConfig.setConnectionTimeout(Long.parseLong(properties.getProperty(DAOFactory.CONF_CONNECTION_TIMEOUT, "10000")));

            hikariConfig.addDataSourceProperty("cachePrepStmts",
                    properties.getProperty(DAOFactory.CONF_CACHE_PREPARESTATEMENT, "true"));
            hikariConfig.addDataSourceProperty("prepStmtCacheSize",
                    properties.getProperty(DAOFactory.CONF_PREPARESTATEMENT_CACHE_SIZE, "300"));
            hikariConfig.addDataSourceProperty("prepStmtCacheSqlLimit",
                    properties.getProperty(DAOFactory.CONF_PREPARESTATEMENT_CACHE_LIMIT, "2048"));

            return new HikariDataSource(hikariConfig);
        } catch (Exception e) {
            LOGGER.error("create HikariConfig data source error {} ", e);
        }
        return null;
    }
}

DAOFactoryImpl的实现

package co.yhy.api.persistence.impl;

import co.yhy.api.persistence.*;

public class DAOFactoryImpl extends DAOFactory {

    private static volatile DAOFactoryImpl instance = null;

    private DAOFactoryImpl() {
    }

    public static DAOFactoryImpl getInstance() {
        if (instance == null) {
            synchronized (DAOFactoryImpl.class) {
                if (instance == null) {
                    instance = new DAOFactoryImpl();
                }
            }
        }
        return instance;
    }

    @Override
    public IDeviceDAO getHistoryDAO() { return new HistoryDAO(); }

   @Override
    public IConfigDAO getConfigDAO() { return new ConfigDAO(); }

}

package co.yhy.api.persistence;

import co.yhy.api.persistence.impl.DAOFactoryImpl;

public abstract class DAOFactory {
    public static final String CONF_JDBC_URL = "data_source.jdbc_url";
    public static final String CONF_USERNAME = "data_source.username";
    public static final String CONF_PASSWORD = "data_source.password";
    public static final String CONF_MAX_POOLSIZE = "data_source.maximumPoolSize";
    public static final String CONF_AUTO_COMMIT = "data_source.autoCommit";
    public static final String CONF_DATA_SOURCE_CLASS_NAME = "data_source.dataSourceClassName";
    public static final String CONF_DRIVER_CLASSNAME = "data_source.driverClassName";
    public static final String CONF_CACHE_PREPARESTATEMENT = "data_source.cachePrepStmts";
    public static final String CONF_PREPARESTATEMENT_CACHE_SIZE = "data_source.prepStmtCacheSize";
    public static final String CONF_PREPARESTATEMENT_CACHE_LIMIT = "data_source.prepStmtCacheSqlLimit";
    public static final String CONF_LEAK_DETECTION_THRESHOLD = "data_source.leakDetectionThreshold";
    public static final String CONF_MAXLIFETIME = "data_source.maxLifetime";
    public static final String CONF_CONNECTION_TIMEOUT = "data_source.connectionTimeout";

    public static final int MYSQL = 1;

    public static DAOFactory getDAOFactory(
            int whichFactory) {
        switch (whichFactory) {
            case MYSQL:
                return DAOFactoryImpl.getInstance();
            default:
                return null;
        }
    }

    public abstract IHistoryDAO getHistoryDAO();

    public abstract IConfigDAO getConfigDAO();

}

ConfigDAO的实现和使用

实现ConfigMapper.java，包含sql的接口；
实现ConfigMapper.xml，具体每个sql的实现，并将ConfigMapper.xml路径添加到mybatis-config.xml中；
实现IConfigDAO接口，实现ConfigDAO 实现config表的所有增删改查操作。

1. 实现ConfigMapper.java，包含sql的接口

package co.yhy.api.persistence.mappers;

import org.apache.ibatis.annotations.Param;

import java.sql.Timestamp;

public interface ConfigMapper {

    int createConfig(@Param("project") String project, @Param("confName") String confName, @Param("confValue") String value,
                     @Param("updateTime") Timestamp updateTime);

    String getConfig(@Param("project") String project, @Param("confName") String confName);

    int deleteConfig(@Param("project") String project, @Param("confName") String confName);

}

2. 实现ConfigMapper.xml，具体每个sql的实现

<?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='co.yhy.api.persistence.mappers.ConfigMapper'>

    <insert id='createConfig'>
        INSERT INTO configs (project, conf_name, conf_value) VALUES
        ( #{project, jdbcType=VARCHAR}, #{confName, jdbcType=VARCHAR}, #{confValue, jdbcType=VARCHAR} )
        ON DUPLICATE KEY UPDATE conf_value=#{confValue}, update_time=#{updateTime}
    </insert>

    <select id="getConfig" resultType='String'>
        SELECT conf_value FROM configs
        <where>
            project=#{project} AND conf_name=#{confName}
        </where>
    </select>

    <delete id="deleteConfig">
        DELETE FROM configs
        <where>
            project=#{project} AND conf_name=#{confName}
        </where>
    </delete>

</mapper>

3. 实现接口IConfigDAO和ConfigDAO和BasicDAO

package co.yhy.api.persistence;


public interface IConfigDAO {

    int createConfig(String project, String confName, String value) throws PersistenceException;

    String readConfig(String project, String confName) throws PersistenceException;

    int deleteConfig(String project, String confName) throws PersistenceException;

}

package co.yhy.api.persistence.impl;

import co.yhy.api.persistence.BasicDAO;
import co.yhy.api.persistence.IConfigDAO;
import co.yhy.api.persistence.PersistenceException;
import co.yhy.api.persistence.mappers.ConfigMapper;
import co.yhy.api.util.ApiUtility;

import java.sql.Timestamp;

public class ConfigDAO extends BasicDAO implements IConfigDAO {

    @Override
    public int createConfig(String project, String confName, String confValue) throws PersistenceException {
        return autoCommitWithReturn("create config fail", sqlSession -> {
            ConfigMapper configMapper = sqlSession.getMapper(ConfigMapper.class);
            Timestamp updateTime = ApiUtility.getCurrentTimestamp();
            return configMapper.createConfig(project, confName, confValue, updateTime);
        });
    }

    @Override
    public String readConfig(String project, String confName) throws PersistenceException {
        return query("read config fail", sqlSession -> {
            ConfigMapper configMapper = sqlSession.getMapper(ConfigMapper.class);
            return configMapper.getConfig(project, confName);
        });
    }

    @Override
    public int deleteConfig(String project, String confName) throws PersistenceException {
        return autoCommitWithReturn("delete config fail", sqlSession -> {
            ConfigMapper configMapper = sqlSession.getMapper(ConfigMapper.class);
            return configMapper.deleteConfig(project, confName);
        });
    }
}

package co.yhy.api.persistence;

import co.yhy.falcon.Falcon;
import co.yhy.api.exception.InvalidClientIdException;
import co.yhy.common.Constants;
import co.yhy.api.ApiConstants;
import org.apache.ibatis.session.SqlSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class BasicDAO {
    private static final Logger LOGGER = LoggerFactory.getLogger(BasicDAO.class);

    public interface DBAutoCommit {
        void commit(SqlSession sqlSession) throws PersistenceException, InvalidClientIdException;
    }

    public interface DBQuery<T> {
        T query(SqlSession sqlSession) throws PersistenceException, InvalidClientIdException;
    }

    public interface DBAutoCommitWithReturn<T> {
        T commitWithReturn(SqlSession sqlSession) throws PersistenceException;
    }

    protected void autoCommit(String errMsg, DBAutoCommit operation) throws PersistenceException {
        SqlSession sqlSession = null;
        try {
            sqlSession = MyBatisSqlSession.getInstance().getSqlSessionFactory().openSession();
            operation.commit(sqlSession);
            sqlSession.commit();
        } catch (Exception e) {
            rollback(sqlSession);
            LOGGER.error(errMsg, e);
            Falcon.sum(Constants.DB_OPERATION_FAIL_NUM, 1);
            throw new PersistenceException(e);
        } finally {
            close(sqlSession);
        }
    }

    @SuppressWarnings(value = "unchecked")
    protected <T> T autoCommitWithReturn(String errMsg, DBAutoCommitWithReturn operation) throws PersistenceException{
        SqlSession sqlSession = null;
        try {
            sqlSession = MyBatisSqlSession.getInstance().getSqlSessionFactory().openSession();
            T t = (T) operation.commitWithReturn(sqlSession);
            sqlSession.commit();
            return t;
        } catch (Exception e) {
            rollback(sqlSession);
            LOGGER.error(errMsg, e);
            Falcon.sum(Constants.DB_OPERATION_FAIL_NUM, 1);
            throw new PersistenceException(e);
        } finally {
            close(sqlSession);
        }
    }

    protected <T> T query(String errMsg, DBQuery<T> operation) throws PersistenceException {
        SqlSession sqlSession = null;
        try {
            sqlSession = MyBatisSqlSession.getInstance().getSqlSessionFactory().openSession();
            return operation.query(sqlSession);
        } catch (Exception e) {
            LOGGER.error(errMsg, e);
            Falcon.sum(Constants.DB_OPERATION_FAIL_NUM, 1);
            throw new PersistenceException(e);
        } finally {
            close(sqlSession);
        }
    }


    private void rollback(SqlSession sqlSession) {
        try {
            if (sqlSession != null) {
                sqlSession.rollback();
            }
        } catch (Exception e) {
            LOGGER.error(String.format("Failed to rollback: %s.", e.getMessage()));
        }
    }

    private void close(SqlSession sqlSession) {
        Falcon.sum(ApiConstants.METRIC_DB_OPERATION_NUM, 1);
        if (sqlSession != null) {
            sqlSession.close();
        }
    }
}

启动mybatis，完成sql操作

ServiceConfig serviceConfig = ServiceConfig.getInstance();
boolean result = serviceConfig.init(confFilePath);
MyBatisSqlSession.getInstance().init(serviceConfig);
DAOFactory factory = DAOFactory.getDAOFactory(DAOFactory.MYSQL);
configDAO = factory.getConfigDAO();
configDAO.createConfig(......);
configDAO.readConfig(......);
configDAO.deleteConfig(......);

人面猴
序言：七十年代末，一起剥皮案震惊了整个滨河市，随后出现的几起案子，更是在滨河造成了极大的恐慌，老刑警刘岩，带你破解...
沈念sama阅读 203,547评论 6赞 477
死咒
序言：滨河连续发生了三起死亡事件，死亡现场离奇诡异，居然都是意外死亡，警方通过查阅死者的电脑和手机，发现死者居然都...
沈念sama阅读 85,399评论 2赞 381
救了他两次的神仙让他今天三更去死
文/潘晓璐我一进店门，熙熙楼的掌柜王于贵愁眉苦脸地迎上来，“玉大人，你说我怎么就摊上这事。” “怎么了？”我有些...
开封第一讲书人阅读 150,428评论 0赞 337
道士缉凶录：失踪的卖姜人
文/不坏的土叔我叫张陵，是天一观的道长。经常有香客问我，道长，这世上最难降的妖魔是什么？我笑而不...
开封第一讲书人阅读 54,599评论 1赞 274
港岛之恋（遗憾婚礼）
正文为了忘掉前任，我火速办了婚礼，结果婚礼上，老公的妹妹穿的比我还像新娘。我一直安慰自己，他们只是感情好，可当我...
茶点故事阅读 63,612评论 5赞 365
恶毒庶女顶嫁案：这布局不是一般人想出来的
文/花漫我一把揭开白布。她就那样静静地躺着，像睡着了一般。火红的嫁衣衬着肌肤如雪。梳的纹丝不乱的头发上，一...
开封第一讲书人阅读 48,577评论 1赞 281
城市分裂传说
那天，我揣着相机与录音，去河边找鬼。笑死，一个胖子当着我的面吹牛，可吹牛的内容都是我干的。我是一名探鬼主播，决...
沈念sama阅读 37,941评论 3赞 395
双鸳鸯连环套：你想象不到人心有多黑
文/苍兰香墨我猛地睁开眼，长吁一口气：“原来是场噩梦啊……” “哼！你这毒妇竟也来了？” 一声冷哼从身侧响起，我...
开封第一讲书人阅读 36,603评论 0赞 258
万荣杀人案实录
序言：老挝万荣一对情侣失踪，失踪者是张志新（化名）和其女友刘颖，没想到半个月后，有当地人在树林里发现了一具尸体，经...
沈念sama阅读 40,852评论 1赞 297
护林员之死
正文独居荒郊野岭守林人离奇死亡，尸身上长有42处带血的脓包…… 初始之章·张勋以下内容为张勋视角年9月15日...
茶点故事阅读 35,605评论 2赞 321
白月光启示录
正文我和宋清朗相恋三年，在试婚纱的时候发现自己被绿了。大学时的朋友给我发了我未婚夫和他白月光在一起吃饭的照片。...
茶点故事阅读 37,693评论 1赞 329
活死人
序言：一个原本活蹦乱跳的男人离奇死亡，死状恐怖，灵堂内的尸体忽然破棺而出，到底是诈尸还是另有隐情，我是刑警宁泽，带...
沈念sama阅读 33,375评论 4赞 318
日本核电站爆炸内幕
正文年R本政府宣布，位于F岛的核电站，受9级特大地震影响，放射性物质发生泄漏。R本人自食恶果不足惜，却给世界环境...
茶点故事阅读 38,955评论 3赞 307
男人毒药：我在死后第九天来索命
文/蒙蒙一、第九天我趴在偏房一处隐蔽的房顶上张望。院中可真热闹，春花似锦、人声如沸。这庄子的主人今日做“春日...
开封第一讲书人阅读 29,936评论 0赞 19
一桩弑父案，背后竟有这般阴谋
文/苍兰香墨我抬头看了看天上的太阳。三九已至，却和暖如春，着一层夹袄步出监牢的瞬间，已是汗流浃背。一阵脚步声响...
开封第一讲书人阅读 31,172评论 1赞 259
情欲美人皮
我被黑心中介骗来泰国打工，没想到刚下飞机就差点儿被人妖公主榨干…… 1. 我叫王不留，地道东北人。一个月前我还...
沈念sama阅读 43,970评论 2赞 349
代替公主和亲
正文我出身青楼，却偏偏与公主长得像，于是被迫代替她去往敌国和亲。传闻我的和亲对象是个残疾皇子，可洞房花烛夜当晚...
茶点故事阅读 42,414评论 2赞 342

集成Mybatis

集成Mybatis到项目的步骤

内部机制：

MyBatisSqlSession的实现

mybatis-config.xml文件的配置

HikariDataSourceFactory的实现

DAOFactoryImpl的实现

ConfigDAO的实现和使用

1. 实现ConfigMapper.java，包含sql的接口

2. 实现ConfigMapper.xml，具体每个sql的实现

3. 实现接口IConfigDAO和ConfigDAO和BasicDAO

启动mybatis，完成sql操作

推荐阅读更多精彩内容