Mybatis自定义typeHandle过程解析

CREATE TABLE `customer` (
 `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',
 `customer_name` varchar(255) DEFAULT NULL COMMENT '顾客名称',
 `gender` varchar(255) DEFAULT NULL COMMENT '性别',
 `telephone` varchar(255) DEFAULT NULL COMMENT '电话号码',
 `register_time` timestamp NULL DEFAULT NULL COMMENT '注册时间',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='顾客表';

public class Customer {
  // 主键
  private Long id;
  // 客户姓名
  private String customer_name;
  // 性别
  private String gender;
  // 电话
  private String telephone;
  // 注册时间
  private Long register_time;
  // 省略 set get
 } 

/**
 * @Author lsc
 * <p> 一个无聊的业务逻辑 输入的是时间戳，到数据库中的是 timestamp 格式 输出的又是时间戳 </p>
 */
@MappedJdbcTypes(JdbcType.TIMESTAMP)
@MappedTypes(Long.class)
public class TimeStringHandler<T> extends BaseTypeHandler<T> {


  public void setNonNullParameter(PreparedStatement preparedStatement, int i, T t, JdbcType jdbcType) throws SQLException {
    // 将 时间戳转为 LocalDateTime
    LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochSecond((java.lang.Long) t), ZoneOffset.ofHours(8));
    // 参数设置
    System.out.println("业务逻辑1");
    preparedStatement.setString(i,localDateTime.toString());
  }

  public T getNullableResult(ResultSet resultSet, String s) throws SQLException {
    System.out.println("业务逻辑2");
    String time = resultSet.getString(s);
    LocalDateTime localDateTime = LocalDateTime.parse(time, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    Long second = localDateTime.toEpochSecond(ZoneOffset.ofHours(8));
    return (T) second;
  }

  public T getNullableResult(ResultSet resultSet, int i) throws SQLException {
    System.out.println("业务逻辑3");
    String time = resultSet.getString(i);
    LocalDateTime localDateTime = LocalDateTime.parse(time, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    Long second = localDateTime.toEpochSecond(ZoneOffset.ofHours(8));
    return (T) second;
  }

  public T getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
    System.out.println("业务逻辑4");
    String time = callableStatement.getString(i);
    LocalDateTime localDateTime = LocalDateTime.parse(time, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    Long second = localDateTime.toEpochSecond(ZoneOffset.ofHours(8));
    return (T) second;
  }
}

public interface CustomerMapper {

  // 添加客户
  int addCustomer(Customer customer);
  // 查询客户
  List<Customer> getCustomer();
}

<?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">

<mapper namespace="com.zszxz.typehandler.mapper.CustomerMapper">

  <resultMap id="customerMap" type="customer" autoMapping="true">
    <result column="register_time" property="register_time" typeHandler="com.zszxz.typehandler.handler.TimeStringHandler"></result>
  </resultMap>

  <select id="getCustomer" resultMap="customerMap" >
    select * from `customer`
  </select>

  <insert id="addCustomer" parameterType="customer">
     insert into `customer`(
      `customer_name`,
      `gender`,
      `telephone`,
      `register_time`
     )values (
      #{customer_name},
      #{gender},
      #{telephone},
      #{register_time,javaType=Long,jdbcType=TIMESTAMP,typeHandler=com.zszxz.typehandler.handler.TimeStringHandler}
     )
  </insert>
</mapper>

/**
 * @Author lsc
 * <p> </p>
 */
@RunWith(JUnit4.class)
public class TypeHandlerTest {

  SqlSession sqlSession = null;

  // @Before 会在执行测试类之前执行该方法
  @Before
  public void before() throws IOException {
    // 资源路径 resource目录下
    String resource = "mybatis-config.xml";
    // 配置mybatis获得输入流
    InputStream inputStream = Resources.getResourceAsStream(resource);
    // 创建 SqlSessionFactory
    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    //从 SqlSessionFactory 中获取 SqlSession
    sqlSession= sqlSessionFactory.openSession();
  }

  @Test
  public void testInsert(){
    // 获得mapper的形式
    CustomerMapper mapper = sqlSession.getMapper(CustomerMapper.class);
    Customer customer = new Customer();
    customer.setCustomer_name("知识追寻者");
    customer.setRegister_time(1580739214L);
    customer.setGender("男");
    customer.setTelephone("999");
    // 添加客户
    mapper.addCustomer(customer);
    sqlSession.commit();
    sqlSession.close();
  }

  @Test
  public void testSelect(){
    // 获得mapper的形式
    CustomerMapper mapper = sqlSession.getMapper(CustomerMapper.class);
    List<Customer> customerList = mapper.getCustomer();
    for (Customer customer :customerList){
      System.out.println(customer.getCustomer_name());
      System.out.println(customer.getRegister_time());
    }
    sqlSession.commit();
    sqlSession.close();
  }
}