Mybatis3 typeHandler 装换某个字段的值

Mybatis typeHandler

typeHandler作用将jdbcType和javaType的值做类型转换

环境

1. spring boot
2. mybatis 3
   mybatis3与spring boot 集成请参考之前的文章

编写自己的typeHandler

实现 org.apache.ibatis.type.TypeHandler 接口， 或继承一个很便利的类 org.apache.ibatis.type.BaseTypeHandler
更详细的介绍请参考官方地址

typeHandler实现类MyTypeHandler

package com.example.handler;

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

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


public class MyTypeHandler extends BaseTypeHandler<String> {
    @Override
    public void setNonNullParameter(PreparedStatement preparedStatement, int i, String s, JdbcType jdbcType) throws SQLException {
        preparedStatement.setString(i, "自定义类型处理器" + s);
    }

    @Override
    public String getNullableResult(ResultSet resultSet, String s) throws SQLException {
        return "自定义handler查询："+resultSet.getString(s);
    }

    @Override
    public String getNullableResult(ResultSet resultSet, int i) throws SQLException {
        return null;
    }

    @Override
    public String getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
        return null;
    }
}

springboot中注册自己的typeHandler实现类

mybatis:
  type-handlers-package: com.example.handler

详细配置参考mybatis-spring-boot-autoconfigure官方地址

配置需要做转换处理的字段

<?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.example.mapper.TblUserMapper">
  <resultMap id="BaseResultMap" type="com.example.model.TblUser">
    <result column="id" jdbcType="INTEGER" property="id" />
    <result column="name" jdbcType="VARCHAR" property="name" typeHandler="com.example.handler.MyTypeHandler"/>
    <result column="password" jdbcType="VARCHAR" property="password" />
  </resultMap>
  <insert id="insert" parameterType="com.example.model.TblUser">
    insert into tbl_user (id, name, password
      )
    values (#{id,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR,typeHandler=com.example.handler.MyTypeHandler}, #{password,jdbcType=VARCHAR}
      )
  </insert>
  <select id="selectAll" resultMap="BaseResultMap">
    select id, name, password
    from tbl_user
  </select>
</mapper>

通过postman查看测试结果

插入数据测试结果

查询数据测试结果