mybatis中BaseTypeHandler的使用

朴灿烈づ我的快乐病毒、 2024-02-19 08:23 21阅读 0赞

## mybatis中BaseTypeHandler的使用 ##

自定义TypeHandler

package com.cdn.demo.handler;
    
    import org.apache.ibatis.type.BaseTypeHandler;
    import org.apache.ibatis.type.JdbcType;
    
    import java.sql.CallableStatement;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    /**
     * @author 蔡定努
     * @date 2023/11/04 16:51
     */
    public class StringTypeHandler<T> extends BaseTypeHandler<T> {
        
    
    
        @Override
        public void setNonNullParameter(PreparedStatement preparedStatement, int i, T integer, JdbcType jdbcType) throws SQLException {
        
            preparedStatement.setObject(i, integer);
        }
    
        @Override
        public T getNullableResult(ResultSet resultSet, String s) throws SQLException {
        
            System.out.println(resultSet.getObject(s));
            return (T) resultSet.getObject(s);
        }
    
        @Override
        public T getNullableResult(ResultSet resultSet, int i) throws SQLException {
        
            return (T) resultSet.getObject(i);
        }
    
        @Override
        public T getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
        
            return (T) callableStatement.getObject(i);
        }
    }

实体类

package com.cdn.demo.entity;
    
    import com.baomidou.mybatisplus.annotation.TableField;
    import com.baomidou.mybatisplus.annotation.TableName;
    import com.baomidou.mybatisplus.annotation.IdType;
    import com.baomidou.mybatisplus.annotation.TableId;
    import java.io.Serializable;
    
    import com.cdn.demo.handler.StringTypeHandler;
    import lombok.Data;
    import lombok.EqualsAndHashCode;
    import lombok.experimental.Accessors;
    
    /**
     * @author author
     * @since 2023-10-25
     */
    @Data
    @EqualsAndHashCode(callSuper = false)
    @Accessors(chain = true)
    @TableName(value = "person",autoResultMap = true)
    public class Person implements Serializable {
        
    
        private static final long serialVersionUID = 1L;
    
        @TableId(value = "id", type = IdType.AUTO)
        private Integer id;
    
        private Integer userId;
    
        @TableField(typeHandler = StringTypeHandler.class)
        private String job;
    
        private Integer age;
    
    
    }

Mapper

package com.cdn.demo.mapper;
    
    import com.cdn.demo.entity.Person;
    import com.baomidou.mybatisplus.core.mapper.BaseMapper;
    import com.cdn.demo.handler.StringTypeHandler;
    import org.apache.ibatis.annotations.*;
    
    import java.math.BigDecimal;
    import java.util.List;
    
    /**
     * <p>
     *  Mapper 接口
     * </p>
     *
     * @author author
     * @since 2023-10-25
     */
    public interface PersonMapper extends BaseMapper<Person> {
        
    
    
        @Select("select * from person where id = 1")
        @Results({
        
                @Result(property = "job", column = "job", javaType = BigDecimal.class, typeHandler = StringTypeHandler.class)
        })
        List<Person> person();
    
    
    
        List<Person> anno();
    
    
    
    
    }

XML

<?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.cdn.demo.mapper.PersonMapper">
    
        
        <resultMap id="BaseResultMap" type="com.cdn.demo.entity.Person">
            <id column="id" property="id" />
            <result column="user_id" property="userId" />
            <result column="job" property="job" typeHandler="com.cdn.demo.handler.StringTypeHandler"/>
            <result column="age" property="age" />
        </resultMap>
    
        
        <sql id="Base_Column_List">
            id, user_id, job, age
        </sql>
    
        <select id="anno" resultMap="BaseResultMap">
            select <include refid="Base_Column_List"/> from person where id =1
        </select>
    
    </mapper>

Controller

package com.cdn.demo.controller;
    
    
    import cn.hutool.core.util.RandomUtil;
    import com.cdn.demo.entity.Person;
    import com.cdn.demo.mapper.PersonMapper;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    
    /**
     * <p>
     *  前端控制器
     * </p>
     *
     * @author author
     * @since 2023-10-25
     */
    @RestController
    @RequestMapping("/person")
    public class PersonController {
        
    
        @Resource
        private PersonMapper personMapper;
    
    
        /**
         * xml方式
         * @author 蔡定努
         */
        @GetMapping("add")
        public void add() {
        
            Person person1 = new Person();
            person1.setUserId(0);
            person1.setJob(RandomUtil.randomString(3));
            person1.setAge(0);
            personMapper.insert(person1);
        }
    
        /**
         * xml的方式
         * @author 蔡定努
         */
        @GetMapping("xml")
        public Object xml() {
        
            return personMapper.person();
        }
    
    
        /**
         * 注解的方式
         * @return
         */
        @GetMapping("anno")
        public Object anno() {
        
            return personMapper.anno();
        }
    
    
        /**
         * plus的方式
         * @return
         */
        @GetMapping("plus")
        public Object plus() {
        
            return personMapper.selectById(1);
        }
    
    
    
    }