Mybatis环境配置及测试详解

 <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.1</version>
 </dependency>

  <?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>
<!--    开启驼峰命名转换，若底层数据库表项为goods_ID,实体类为goodsId ，则自动转换-->
    <setting name="mapUnderscoreToCamelCase" value="true"/>
  </settings>
  <!-- 设置默认指向的数据库 -->
  <environments default="dev">
    <environment id="dev">
      <!-- 采用JDBC方式对数据库事务进行commit/rollback -->
      <transactionManager type="JDBC"></transactionManager>
      <!-- 采用连接池的方式管理数据库连接  -->
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/babytun?useUnicode=true&amp;characterEncoding=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
      </dataSource>
    </environment>
  </environments>
</configuration>

public class MybatisUtils {
  //利用static静态 属于类而不属于对象 ， 保证全局唯一
  private static SqlSessionFactory sqlSessionFactory = null ;
  //利用静态块在初始化类时实力话SqlSessionFactory
  static {
    Reader reader = null;
    try {
      reader = Resources.getResourceAsReader("mybatis-config.xml");
      sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader) ;
    } catch (IOException e) {
      e.printStackTrace();
      //初始化过程中出现的异常
      throw new ExceptionInInitializerError(e) ;
    }
  }

  /**
   * 创建一个新的sqlsession对象
   * @return sqlsession对象
   * */

  public static SqlSession openSession(){
    return sqlSessionFactory.openSession() ;
  }

  public static void closeSession(SqlSession sqlSession){
    if(sqlSession != null ){
      sqlSession.close();
    }
  }

}

<?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">

 <mappers>
    <mapper resource="mappers/goods.xml" />
    <mapper resource="mappers/goods_detail.xml" />
 </mappers>

 <settings>
<!--    开启驼峰命名转换，若底层数据库表项为goods_ID,实体类为goodsId ，则自动转换-->
    <setting name="mapUnderscoreToCamelCase" value="true"/>
 </settings>

import java.io.Reader;

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

import com.yiibai.mybatis.models.*;

/**
 * 
 * @author yiibai
 * @copyright //www.jb51.net
 * @date 2015/09/22
 */
public class HelloWord {
 private static SqlSessionFactory sqlSessionFactory;
 private static Reader reader;

 static {
 try {
  reader = Resources.getResourceAsReader("config/Configure.xml");
  sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
 } catch (Exception e) {
  e.printStackTrace();
 }
 }
 public static SqlSessionFactory getSession() {
 return sqlSessionFactory;
 }
 /**
 * @param args
 */
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 SqlSession session = sqlSessionFactory.openSession();
 try {
  User user = (User) session.selectOne(
   "com.yiibai.mybatis.models.UserMapper.GetUserByID", 1);
  if(user!=null){
  String userInfo = "名字："+user.getName()+", 所属部门："+user.getDept()+", 主页："+user.getWebsite();
  System.out.println(userInfo);
  }
 } finally {
  session.close();
 }
 }
}