抽取Mybatis工具类

1 抽取Mybatis工具类

public class MybatisUtil {
    private static SqlSessionFactory sqlSessionFactory;

    //创建ThreadLocal绑定当前线程中的SqlSession
    private static final ThreadLocal<SqlSession> tl = new ThreadLocal<>();

    static { //加载配置文件，并构建工厂
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 得到 sqlsession
     * @return
     */
    public static SqlSession openSession() {
        SqlSession sqlSession = tl.get();
        if (sqlSession == null) {
            sqlSession = sqlSessionFactory.openSession();
            tl.set(sqlSession);
        }
        return sqlSession;
    }

    /**
     * 事务提交
     */
    public static void commit() {
        SqlSession sqlSession = openSession();
        sqlSession.commit();
    }

    /**
     * 事务回滚
     */
    public static void rollback() {
        SqlSession sqlSession = openSession();
        sqlSession.rollback();
        closeSession();
    }

    /**
     * 关闭SqlSession
     */
    public static void closeSession() {
        SqlSession sqlSession = tl.get();
        sqlSession.close();
        commit();
    }

    /**
     * 获得mapper对象
     * @param mapper
     * @param <T>
     * @return
     */
    public static <T> T getMapper(Class<T> mapper) {
        SqlSession sqlSession = openSession();
        return sqlSession.getMapper(mapper);
    }
}

2 使用：

public class UtilTest {
    public static void main(String[] args) {
        UserMapper mapper = MybatisUtil.getMapper(UserMapper.class);
        User user = mapper.findById(1);
        System.out.println("------------------------------------");
        System.out.println(user);
    }
}