MyBatismybatis-自定义typeHandler

 一、自定义typeHandler 直接促成 TypeHandler<T>  也得以一连 BaseTypeHandler<T>,大家接纳继续吧。

package com.yihaomen.mybatis.type;

import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;

/**
 *   
 *  @ProjectName: springmvc-mybatis 
 *  @Description: 自定义处理日期Hander,
 *                将Date类型转换为时间戳字符串戳存入到数据库中
 *  1.@MappedJdbcTypes定义的是JdbcType类型,这里的类型不可自己随意定义,
 *   必须要是枚举类org.apache.ibatis.type.JdbcType所枚举的数据类型。
 *  2.@MappedTypes定义的是JavaType的数据类型,描述了哪些Java类型可被拦截。
 *  3.在我们启用了我们自定义的这个TypeHandler之后,数据的读写都会被这个类所过滤
 */
@MappedTypes({Date.class})
@MappedJdbcTypes(JdbcType.VARCHAR)
public class MyDateTypeHandler extends BaseTypeHandler<Date> {
    /**
     * 将时间戳字符串存入数据库
     */
    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, Date parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, String.valueOf(parameter.getTime()));
    }

    /**
     * 把时间戳类型的字符串取出转换为Date
     */
    @Override
    public Date getNullableResult(ResultSet rs, String columnName) throws SQLException {
        return new Date(rs.getLong(columnName));
    }

    /**
     * 把时间戳类型的字符串取出转换为Date
     */
    @Override
    public Date getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        return new Date(rs.getLong(columnIndex));
    }

    /**
     * 把时间戳类型的字符串取出转换为Date
     */
    @Override
    public Date getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        return cs.getDate(columnIndex);
    }
}

 

参考文献:

[1] 杨开振 著,《深切浅出MyBatis技术原理与实战》,
电子工业出版社,2016.09

[2]
个人博客,http://blog.csdn.net/u012702547/article/details/54572679

 

 二、在User.xml文件中写<resultMap/>、<select/>和<insert/>

<?xml version="1.0" encoding="UTF-8" ?>
<resultMap id="resultListUser" type="User">
  <id column="id" property="id" />
  <result column="userName" property="userName" />
  <result column="userAge" property="userAge" />
  <result column="userAddress" property="userAddress" />
  <result column="reg_time" property="regTime" javaType="java.util.Date" jdbcType="VARCHAR" typeHandler="com.yihaomen.mybatis.type.MyDateTypeHandler"/>
</resultMap>
<select id="selectUserById2" parameterType="int" resultMap="resultListUser">
    select * from user where id = #{id}
</select>
<insert id="addUser" parameterType="User" useGeneratedKeys="true" keyProperty="id"> 
  insert into user(userName,userAge,userAddress,reg_time) values(#{userName},#{userAge}, #{userAddress}, 
  #{regTime,javaType=Date,jdbcType=VARCHAR,typeHandler=com.yihaomen.mybatis.type.MyDateTypeHandler}) 
</insert>

 https://gitee.com/huayicompany/springmvc-mybatis.git

现象一:有个java.util.Date在存入数据库的时候自动转换为timestamp时间戳,从数据库取值的时候把时光戳自动转换为java.util.Date

表结构

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `userName` varchar(50) DEFAULT NULL,
  `userAge` int(11) DEFAULT NULL,
  `userAddress` varchar(200) DEFAULT NULL,
  `reg_time` varchar(200) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

三、写UserMapper

package com.yihaomen.mybatis.dao;

import com.yihaomen.mybatis.model.User;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UserMapper {
    public User selectUserById2(int id);
    public void addUser(User user);
}

 

 

 三、测试一下

import com.yihaomen.mybatis.dao.UserMapper;
import com.yihaomen.mybatis.model.User;
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.Reader;
import java.util.Date;
/**
 *  添加
 */
public class TestAddUser {
    private static SqlSessionFactory sqlSessionFactory;
    private static Reader reader;
    static {
        try {
            reader = Resources.getResourceAsReader("configuration.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSessionFactory getSession() {
        return sqlSessionFactory;
    }
    public static void main(String[] args) {
        addUser();
    }
    public static void addUser() {
        User user = new User();
        user.setUserName("spring");
        user.setUserAge("101");
        user.setUserAddress("hangzhou,xihu");
        user.setRegTime(new Date());
        SqlSession session = sqlSessionFactory.openSession();
        try {

            UserMapper userMapper = session.getMapper(UserMapper.class);
            userMapper.addUser(user);
            session.commit();
            System.out.println("当前增加的用户 id为:" + user.getId());
        } catch (Exception e) {
            session.rollback();
        }finally {
            session.close();
        }

    }
}

package user;

import com.yihaomen.mybatis.dao.UserMapper;
import com.yihaomen.mybatis.model.User;
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.Reader;
import java.util.List;

/**
 *   
 *  @ProjectName: springmvc-mybatis 
 *  @Description: 查找
 */
public class TestGetUser {
    private static SqlSessionFactory sqlSessionFactory;
    private static Reader reader;
    static {
        try {
            reader = Resources.getResourceAsReader("configuration.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSessionFactory getSession() {
        return sqlSessionFactory;
    }
    public static void findUserById(int id){
        SqlSession session = sqlSessionFactory.openSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserById2(id);
        for(User u : users) {
            System.out.println(u.getRegTime());
        }
    }

    public static void main(String[] args) {
        findUserById(3);
    }
}

 

 在configuration.xml中注册typeHandler

<?xml version="1.0" encoding="UTF-8" ?>
<!--
        注册typeHandler,注册有两种不同的方式
        1.可以像下面这样一个类一个类的注册
    -->
    <typeHandlers>
        <typeHandler handler="com.yihaomen.mybatis.type.MyDateTypeHandler" />
    </typeHandlers>
    <!--2.也可以直接注册一个包中所有的typeHandler-->
    <!--<typeHandlers>
        <package name="com.yihaomen.mybatis.type"/>
    </typeHandlers>-->

如此那般安顿完毕未来,当大家进行数据库的读取操作的时候,秒数就会自行转为Date对象。

网站地图xml地图