分页查询数据类PagingData

不念不忘少年蓝@ 2022-05-27 02:39 171阅读 0赞

## 分页查询数据类 ##

public class PagingData<T> implements Serializable { 
        // 构造初始化大小
        public ModelTest() {
            list = new ArrayList<T>();
            total= 0;
        }
    
        public ModelTest(List<T> list,Integer total) {
            list = new ArrayList<T>();
            count = 0;
            this.list = list;
            this.total= total;
        }
        private List<T> rows; // 返回数据集合
        private Integer total;  //总条数
        public PagingData(List<T> rows, Integer total)
        {
            this.rows = new ArrayList();
            this.total = Integer.valueOf(0);
            this.rows = rows;
            this.total = total;
        }
    
        public PagingData()
        {
            rows = new ArrayList();
            total = Integer.valueOf(0);
        }
    
        public List getRows()
        {
            return rows;
        }
    
        public void setRows(List rows)
        {
            this.rows = rows;
        }
    
        public Integer getTotal()
        {
            return total;
        }
    
        public void setTotal(Integer total)
        {
            this.total = total;
        }
    
    }

## 用法 ##

@Service
    @Transactional(readOnly = true)
    public class BlockchainCoinRecordServiceImpl implements BlockchainCoinRecordService { 
    
        private static final Logger LOGGER = LoggerFactory.getLogger(BlockchainCoinRecordServiceImpl.class);
    
        @Autowired
        BlockchainCoinRecordMapper blockchainCoinRecordMapper;
    
    
        /** * BlockchainCoinRecord 为实体类 */
        @Override
        public PagingData<BlockchainCoinRecord> selectPage(BlockchainCoinRecord entity) {
            PagingData<BlockchainCoinRecord> pagingData = new PagingData<>();
    
            if (null == entity) {
                LOGGER.warn("select entity page, but entity is null...");
                return pagingData;
            }
    
            Integer queryCount = blockchainCoinRecordMapper.selectByIndexCount(entity);
            pagingData.setTotal(queryCount);
    
            if (null != queryCount && queryCount <= 0) {
                LOGGER.info("select entity page , but count {} == 0 ...", queryCount);
                return pagingData;
            }
    
            List<BlockchainCoinRecord> entitys = selectByIndex(entity);
            pagingData.setRows(entitys);
            return pagingData;
        }
    
        @Override
        public List<BlockchainCoinRecord> selectByIndex(BlockchainCoinRecord entity) {
            List<BlockchainCoinRecord> entitys = new ArrayList<>();
            if (entity == null) {
                LOGGER.warn("select entity by index, but entity is null ...");
                return entitys;
            }
            return blockchainCoinRecordMapper.selectByIndex(entity);
        }
    
    }

## mapper 映射 ##

<?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.hesvit.mapper.BlockchainCoinRecordMapper">
        <sql id="baseColumns">
            a.id, a.user_id, a.coin, a.type, a.remark, a.status,
            a.create_user_id, a.create_time, a.update_user_id, a.update_time
        </sql>
    
    <sql id="whereClause">
            <trim prefix="WHERE" prefixOverrides="AND">
                <if test="id != null">
                    AND ${columnPrefix}id = #{id}
                </if>
                <if test="userId != null">
                    AND ${columnPrefix}user_id = #{userId}
                </if>
                <if test="coin != null">
                    AND ${columnPrefix}coin = #{coin}
                </if>
                <if test="type != null">
                    AND ${columnPrefix}type = #{type}
                </if>
                <if test="remark != null">
                    AND ${columnPrefix}remark = #{remark}
                </if>
                <if test="status != null and status != -1">
                    AND ${columnPrefix}status = #{status}
                </if>
                <if test="createUserId != null"> 
                    AND ${columnPrefix}create_user_id = #{createUserId}
                </if>
                <if test="createTime != null">
                    AND ${columnPrefix}create_time = #{createTime}
                </if>
                <if test="updateUserId != null">
                    AND ${columnPrefix}update_user_id = #{updateUserId}
                </if>
                <if test="updateTime != null">
                    AND ${columnPrefix}update_time = #{updateTime}
                </if>
                <if test="startDate != null">
                    AND ${columnPrefix}create_time > #{startDate}
                </if>
                <if test="endDate != null">
                    AND ${columnPrefix}create_time < #{endDate}
                </if>
            </trim>
        </sql>
    <select id="selectByIndexCount" parameterType="BlockchainCoinRecord" resultType="int">
        SELECT count(1)
        FROM t_blockchain_coin_record a
        <include refid="whereClause">
            <property name="columnPrefix" value="a." />
        </include>
    </select>
    
    <select id="selectByIndex" parameterType="BlockchainCoinRecord" resultType="BlockchainCoinRecord">
        SELECT
        <include refid="baseColumns" />
        FROM t_blockchain_coin_record a
        <include refid="whereClause">
            <property name="columnPrefix" value="a." />
        </include>
        group by a.id
        ORDER BY a.id DESC
        <if test="limit != -1">
        LIMIT #{offset} , #{limit}
        </if>
    </select>
    
    </mapper>