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
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
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}
DELETE FROM configs
project=#{project} AND conf_name=#{confName}
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 query(SqlSession sqlSession) throws PersistenceException, InvalidClientIdException;
}
public interface DBAutoCommitWithReturn {
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 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 query(String errMsg, DBQuery 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(......);