Mybatis连接工具类MybatisUtils,封装SQLSession的创建和关闭！

总结一下工具类备用：

MybatisUtil：

package com.macw.util;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisUtils {
  private static SqlSessionFactory factory = null;
  private static ThreadLocal<SqlSession> tl = new ThreadLocal<SqlSession>();
  static {
    // 1 读取配置文件 config.xml
    InputStream in = null;
    try {
      in = Resources.getResourceAsStream("mybatis-config.xml");
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      throw new RuntimeException(e);
    }
    // 2 创建SqlSessionFactory
    factory = new SqlSessionFactoryBuilder().build(in);
  }

  public static SqlSession openSession() {
    // 3 创建SqlSession
    SqlSession sqlSession = tl.get();
    if (sqlSession == null) {
      sqlSession = factory.openSession();
      tl.set(sqlSession);
    }
    return sqlSession;

  }

  public static void close(SqlSession sqlSession) {

    if (sqlSession != null) {
      tl.remove();
      sqlSession.close();
    }

  }
}

所用到的mybatis-config.xml文件：

<?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="druid.properties"></properties>

  <!-- <settings>
    打印SQL语句
    <setting name="logImpl" value="LOG4J"/>
  </settings> -->

  <!--  给包起别名  -->
  <typeAliases>
    <typeAlias type="com.macw.entity.User" alias="user"/>
    <package name="com.macw.entity"/>
  </typeAliases>

  <environments default="oracle">
    <environment id="oracle">
      <transactionManager type="JDBC"></transactionManager>
      <dataSource type="POOLED">
        <property name="driver" value="${DriverClassName}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
        <!-- <property name="initialSize" value="${initialSize}"/>
        <property name="maxActive" value="${maxActive}"/>
        <property name="maxWait" value="${maxWait}"/> -->
      </dataSource>
    </environment>

  </environments>

  <!-- mapper文件的映射 -->
  <mappers>
    <mapper resource="com/macw/dao/mapper/UserMapper.xml"/>

  </mappers>

</configuration>

上面xml所用到的druid.properties文件：

连接Oracle数据库的配置文件

DriverClassName=oracle.jdbc.OracleDriver
url=jdbc:oracle:thin:@localhost:1521:xe
username=macw
password=macw
initialSize=10
maxActive=50
maxWait=60000

Mybatis工具类在ServiceImpl类下的使用：

package com.macw.service.impl;

import java.util.List;

import org.apache.ibatis.session.SqlSession;

import com.macw.dao.OrderDao;
import com.macw.entity.Order;
import com.macw.service.OrderService;
import com.macw.util.MyBatisUtils;

/**
 * @author 超伟
 * @2019年7月16日 上午10:41:20
 * @博客：https://blog.csdn.net/MacWx
 */
public class OrderServiceImpl implements OrderService {
  private OrderDao dao; 
  /* (non-Javadoc)
   * @see com.macw.service.OrderService#insertOrder(com.macw.entity.Order)
   */
  @Override
  public void insertOrder(Order order) {
    // TODO Auto-generated method stub
    SqlSession sqlSession = MyBatisUtils.openSession();
    dao = sqlSession.getMapper(OrderDao.class);
    try {
      dao.insertOrder(order);
      sqlSession.commit();
    } catch (Exception e) {
      // TODO: handle exception
      sqlSession.rollback();
    } finally {
      MyBatisUtils.close(sqlSession);
    }
  }
}

log4j.properties：

log4j.rootLogger=DEBUG, stdout

# SqlMap logging configuration...
log4j.logger.com.ibatis=DEBUG
log4j.logger.com.ibatis.common.jdbc.SimpleDataSource=DEBUG
log4j.logger.com.ibatis.sqlmap.engine.cache.CacheModel=DEBUG
log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientImpl=DEBUG
log4j.logger.com.ibatis.sqlmap.engine.builder.xml.SqlMapParser=DEBUG
log4j.logger.com.ibatis.common.util.StopWatch=DEBUG
log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG
log4j.logger.java.sql.ResultSet=DEBUG

# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n