mybatis-自定义TypeHandler

字数 434阅读 3413

步骤1:实现TypeHandler接口

import java.sql.CallableStatement;
import java.sql.PreparedStatement;    
import java.sql.ResultSet;    
import java.sql.SQLException;    
    
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedJdbcTypes;
import org.apache.ibatis.type.MappedTypes;
import org.apache.ibatis.type.TypeHandler;
    
/**  
 * @author   
 * java中的boolean和jdbc中的char之间转换;true-Y;false-N  
 */
//方式一:
@MappedJdbcTypes(JdbcType.CHAR)
@MappedTypes(Boolean.class)
public class BooleanTypeHandler implements TypeHandler {    
    
    /* (non-Javadoc)  
     * @see org.apache.ibatis.type.TypeHandler#getResult(java.sql.ResultSet, java.lang.String)  
     */    
    @Override    
    public Object getResult(ResultSet resultSet, String columnLabel) throws SQLException {
        String str = resultSet.getString(columnLabel);
        Boolean rt = Boolean.FALSE;    
        if (str.equalsIgnoreCase("Y")){
            rt = Boolean.TRUE;    
        }    
        return rt;     
    }

    @Override
    public Object getResult(ResultSet resultSet, int columnIndex) throws SQLException {
        String str = resultSet.getString(columnIndex);
        Boolean rt = Boolean.FALSE;
        if (str.equalsIgnoreCase("Y")){
            rt = Boolean.TRUE;
        }
        return rt;
    }

    /* (non-Javadoc)  
     * @see org.apache.ibatis.type.TypeHandler#getResult(java.sql.CallableStatement, int)  
     */    
    @Override    
    public Object getResult(CallableStatement arg0, int arg1)    
            throws SQLException {    
        Boolean b = arg0.getBoolean(arg1);    
        return b == true ? "Y" : "N";    
    }    
    
    /* (non-Javadoc)  
     * @see org.apache.ibatis.type.TypeHandler#setParameter(java.sql.PreparedStatement, int, java.lang.Object, org.apache.ibatis.type.JdbcType)  
     */    
    @Override    
    public void setParameter(PreparedStatement arg0, int arg1, Object arg2,    
            JdbcType arg3) throws SQLException {    
        Boolean b = (Boolean) arg2;    
        String value = (Boolean) b == true ? "Y" : "N";    
        arg0.setString(arg1, value);    
    }    
}    

步骤2:在Mybatis配置中注册该TypeHandler

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="mapperLocations" value="classpath:dao/mapper/*.xml"></property>
        <property name="typeHandlers" >
            <array>
                <bean class="com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler" />
            </array>
        </property>
        <property name="plugins">
            <array>
                <bean class="com.sankuai.travel.csc.test.dao.interceptor.SqlMonitorInterceptor" />
            </array>
        </property>
    </bean>

步骤3:在映射配置文件中使用该TypeHander(如果第一步使用了注解,此处可以省略)

3.1在resultMap的定义中对对应列定义typeHandler

<resultMap id="BaseResultMap" type="com.sankuai.travel.csc.test.dao.domain.CategoryDO" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="category_type" property="categoryType" jdbcType="INTEGER" />
    <result column="category_name" property="categoryName" jdbcType="VARCHAR" />
    <result column="allocate_time" property="allocateTime" jdbcType="INTEGER" />
    <result column="promise_time" property="promiseTime" jdbcType="INTEGER" />
    <result column="last_operator" property="lastOperator" jdbcType="VARCHAR" />
    <result column="update_time" property="updateTime" jdbcType="TIMESTAMP" />

    <!--写在这里,仅对select语句有效,typeHandler="com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler" -->
    <result column="is_cancel" property="isCancel" jdbcType="CHAR" typeHandler="com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler"/>

    <result column="status1" property="status1" jdbcType="CHAR" />
    <result column="status2" property="status2" jdbcType="CHAR" />
    <result column="phone_list" property="phoneList" jdbcType="VARCHAR" />
    <result column="create_time" property="createTime" jdbcType="TIMESTAMP" />
  </resultMap>

这里只能是在select的时候才会使用自定义的TypeHandler处理对应的映射关系,如果要在insert或者update时使用则需要在sql定义中添加相应的内容

3.2在resultMap的定义中对对应列定义typeHandler

<insert id="insert" parameterType="com.sankuai.travel.csc.test.dao.domain.CategoryDO" >
    <selectKey resultType="java.lang.Integer" keyProperty="id" order="AFTER" >
      SELECT LAST_INSERT_ID()
    </selectKey>
    insert into hotel_order_category (category_type, category_name, allocate_time, 
      promise_time, last_operator, update_time, 
      is_cancel, status1, status2, 
      phone_list, create_time)
    values (#{categoryType,jdbcType=INTEGER}, #{categoryName,jdbcType=VARCHAR}, #{allocateTime,jdbcType=INTEGER}, 
      #{promiseTime,jdbcType=INTEGER}, #{lastOperator,jdbcType=VARCHAR}, #{updateTime,jdbcType=TIMESTAMP}, 
      <!--写在这里,仅对insert有效,注意,没有双引号: typeHandler=com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler -->
      #{isCancel,jdbcType=CHAR,typeHandler=com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler},
      #{status1,jdbcType=CHAR}, #{status2,jdbcType=CHAR},
      #{phoneList,jdbcType=VARCHAR}, #{createTime,jdbcType=TIMESTAMP})
  </insert>

#mybatis-enumtypehandler和enumordinaltypehandler的区别

mybatis对枚举类型提供了两种类型支持:EnumTypeHandler和EnumOrdinalTypeHandler。

  • EnumTypeHandler是mybatis默认的枚举类型转换器,如果pojo类中使用了枚举类型,而配置文件没有指定类型转换类,mybatis将使用EnumTypeHandler处理枚举属性。EnumTypeHandler的将把枚举类的name进行存储,枚举类的name即枚举类名。参考:http://mybatis.github.io/mybatis-3/zh/configuration.html
  • EnumOrdinalTypeHandler是mybatis提供的另一种转换器,顾名思义这个转换类使用了枚举类的ordinal属性作为数据库存储信息,由于ordinal属性是int类型的,按照官网的说明数据库中对应资源应该是int或double类型的,但是个人测试过程中MYSQL的varchar字段也可以存储。
  • 总结:EnumTypeHandler和EnumOrdinalTypeHandler的区别主要是数据库中存储字段的类型差别,由于EnumOrdinalTypeHandler使用枚举类型的ordinal作为存储,所以必须使用数字类型字段存储。
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="mapperLocations" value="classpath:dao/mapper/*.xml"></property>
        <property name="typeHandlers" >
            <array>
                <bean class="com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler" />
                <bean class="com.sankuai.travel.csc.test.dao.typehandler.StringArrayTypeHandler" />
  <!--不需要EnumTypeHandler,默认包含 -->
                <bean class="org.apache.ibatis.type.EnumTypeHandler" >
                    <constructor-arg name="type" value="com.sankuai.travel.csc.test.enums.SimpleStatusEnum" />
                </bean>
<!--需要EnumOrdinalTypeHandler,默认包含 -->
                <bean class="org.apache.ibatis.type.EnumOrdinalTypeHandler" >
                    <constructor-arg name="type" value="com.sankuai.travel.csc.test.enums.SimpleStatusEnum" />
                </bean>
            </array>
        </property>
        <property name="plugins">
            <array>
                <bean class="com.sankuai.travel.csc.test.dao.interceptor.SqlMonitorInterceptor" />
            </array>
        </property>
    </bean>
<resultMap id="BaseResultMap" type="com.sankuai.travel.csc.test.dao.domain.CategoryDO" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="category_type" property="categoryType" jdbcType="INTEGER" />
    <result column="category_name" property="categoryName" jdbcType="VARCHAR" />
    <result column="allocate_time" property="allocateTime" jdbcType="INTEGER" />
    <result column="promise_time" property="promiseTime" jdbcType="INTEGER" />
    <result column="last_operator" property="lastOperator" jdbcType="VARCHAR" />
    <result column="update_time" property="updateTime" jdbcType="TIMESTAMP" />

    <!--方式二:写在这里,仅对select语句有效,typeHandler="com.sankuai.travel.csc.test.dao.typehandler.BooleanTypeHandler" -->
    <result column="is_cancel" property="isCancel" jdbcType="CHAR" />
<!--EnumTypeHandler默认处理类,不需要配置 -->
    <result column="status1" property="status1" jdbcType="CHAR" />
<!--EnumOrdinalTypeHandler需要单独配置 -->
    <result column="status2" property="status2" jdbcType="CHAR" typeHandler="org.apache.ibatis.type.EnumOrdinalTypeHandler" />
    <result column="phone_list" property="phoneList" jdbcType="VARCHAR" />
    <result column="create_time" property="createTime" jdbcType="TIMESTAMP" />
  </resultMap>


参考文章

https://my.oschina.net/amoshuang/blog/134199
mybatis-enumtypehandler和enumordinaltypehandler的区别

推荐阅读更多精彩内容