MyBatis单列工厂的实现

SqlSessionFactoryUtils

package com.utils;

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

/**
 * @author: XDZY
 * @date: 2018/8/8 14:50
 * @description: SessionFactory工厂
 */
public class SqlSessionFactoryUtils {
    private final static Class<SqlSessionFactoryUtils> LOCK = SqlSessionFactoryUtils.class;

    private static SqlSessionFactory sqlSessionFactory = null;

    private SqlSessionFactoryUtils() {
    }

    public static SqlSessionFactory getSqlSessionFactory() {
        synchronized (LOCK) {
            if (sqlSessionFactory != null) {
                return sqlSessionFactory;
            }
            String resource = "com/mybatis-config.xml";
            InputStream inputStream;
            try {
                inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
            return sqlSessionFactory;
        }
    }

    public static SqlSession openSqlSession() {
        if (sqlSessionFactory == null) {
            getSqlSessionFactory();
        }
        return sqlSessionFactory.openSession();
    }
}

Test

package com.main;

import com.mapper.RoleMapper;
import com.pojo.Role;
import com.utils.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;

/**
 * @author: XDZY
 * @date: 2018/8/8 15:12
 * @description: 运行入口
 */
public class TestMain {
    public static void main(String[] args) {
        SqlSession sqlSession = null;
        try {
            sqlSession = SqlSessionFactoryUtils.openSqlSession();
            RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);
            Role role = roleMapper.getRole(1L);
            System.out.println(role.getRoleName());
        } finally {
            if (sqlSession != null) {
                sqlSession.close();
            }
        }
    }
}