raex_back/src/main/java/com/izouma/nineth/service/MetaRankService.java

package com.izouma.nineth.service;

import cn.hutool.core.convert.Convert;
import com.alibaba.fastjson.JSONArray;
import com.izouma.nineth.config.MetaConstants;
import com.izouma.nineth.domain.MetaRank;
import com.izouma.nineth.dto.MetaRankDTO;
import com.izouma.nineth.dto.PageQuery;
import com.izouma.nineth.dto.PageWrapper;
import com.izouma.nineth.exception.BusinessException;
import com.izouma.nineth.repo.MetaRankRepo;
import com.izouma.nineth.utils.JpaUtils;
import lombok.AllArgsConstructor;
import org.apache.commons.collections.CollectionUtils;
import org.springframework.data.domain.Page;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

@Service
@AllArgsConstructor
public class MetaRankService {

    private MetaRankRepo metaRankRepo;

    private MetaUserGoldRecordService metaUserGoldRecordService;

    public Page<MetaRank> all(PageQuery pageQuery) {
        return metaRankRepo.findAll(JpaUtils.toSpecification(pageQuery, MetaRank.class), JpaUtils.toPageRequest(pageQuery));
    }

    public Page<MetaRankDTO> rank(PageQuery pageQuery) {
        Map<String, Object> query = pageQuery.getQuery();
        if (!query.containsKey("id")) {
            throw new BusinessException("排行榜id不存在！");
        }
        Long id = Convert.toLong(query.get("id"));
        if (id.equals(MetaConstants.META_GOLD_RECEIVED_RANK_ID)) {
            return buildPage(pageQuery, metaUserGoldRecordService.rank());
        }
        // ...
        throw new BusinessException("非法排行榜id");
    }

    private Page<MetaRankDTO> buildPage(PageQuery pageQuery, List<Map<String, String>> rank) {
        if (CollectionUtils.isEmpty(rank)) {
            return null;
        }
        JSONArray jsonArray = new JSONArray();
        jsonArray.addAll(rank);
        List<MetaRankDTO> metaRankDTOS = jsonArray.toJavaList(MetaRankDTO.class);
        int page = pageQuery.getPage();
        int size = pageQuery.getSize();
        int start = page * size;
        int totalElements = 0;
        if (CollectionUtils.isEmpty(metaRankDTOS)) {
            return new PageWrapper<>(new ArrayList<MetaRankDTO>(), page,
                    size, totalElements).toPage();
        }
        totalElements = metaRankDTOS.size();
        List<MetaRankDTO> newMetaRankDTOS;
        if (metaRankDTOS.size() < start + size) {
            newMetaRankDTOS = metaRankDTOS.subList(start, metaRankDTOS.size());
            return new PageWrapper<>(newMetaRankDTOS, page,
                    size, totalElements).toPage();
        }
        newMetaRankDTOS = metaRankDTOS.subList(start, start + size);
        return new PageWrapper<>(newMetaRankDTOS, page,
                size, totalElements).toPage();
    }
}