自定义TypeHandler类

自定义TypeHandler类

我写的这个类是根据项目需要写的！

应用场景：数据库的字段类型是int类型的，项目的字段类型是一个自定义对象类型的，需要进行类型转换！

1、创建一个handler类，继承BaseTypeHandler，话不多说，直接放码！

import com.yd.tech.read.entity.StateEntity;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
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;
    public class StateToIntHandler  extends BaseTypeHandler<StateEntity> {
    private  static final Log log = LogFactory.getLog(StateToIntHandler.class);

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, StateEntity parameter, JdbcType jdbcType) throws SQLException {

        Integer aa = parameter.getState();
        if (aa==1){
            ps.setInt(i, 1);
        }else if(aa==0){
            ps.setInt(i, 0);
        }
    }

    @Override
    public StateEntity getNullableResult(ResultSet rs, String columnName) throws SQLException {
        //获取数据库的值
        int ss=rs.getInt(columnName);
        StateEntity state0 = new StateEntity(0);
        StateEntity state1 = new StateEntity(1);

        if(ss==1){
            return state1;
        }else if(ss==0){
            return state0;
        }else{
            return null;
        }

    }

    @Override
    public StateEntity getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        //获取数据库的值
        int ss=rs.getInt(columnIndex);
        StateEntity state0 = new StateEntity(0);
        StateEntity state1 = new StateEntity(1);

        if(ss==1){
            return state1;
        }else if(ss==0){
            return state0;
        }else{
            return null;
        }
    }

    @Override
    public StateEntity getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        //获取数据库的值

        int ss=cs.getInt(columnIndex);
        StateEntity state0 = new StateEntity(0);
        StateEntity state1 = new StateEntity(1);

        if(ss==1){
            return state1;
        }else if(ss==0){
            return state0;
        }else{
            return null;
        }
    }
}

2、配置mabtis-config.xml

    <typeHandlers>
        <typeHandler handler="com.tech.read.handler.StateToIntHandler"/>
    </typeHandlers>

3、mapper.xml中应用

<resultMap id="DataResultMap" type="DataEntity">
        <id column="data_id" property="dataId"/>
        <result column="add_time" property="addTime"/>
        <result column="update_time" property="updateTime"/>
        <result column="state" property="state" typeHandler="com.yd.tech.read.handler.StateToIntHandler"/>
    </resultMap>

<select id="queryAll" resultMap="DataResultMap">
        select * from table
        <include refid="order"/>
  </select>