Solr的学习使用之（六）获取数据列表-SolrDocumentList

以下是我项目中获取新闻数据列表的写法，包括数据总量、数据列表，接下来会贴出分片查询（facet）等高级查询

基本的注释都有了：

private ListPage<News> queryFromSolr(NewsQueryParameters queryParameters, Keyword keyword) {    
        if (queryParameters == null) {
            throw new IllegalArgumentException("查询参数为空");
        }
        ListPage<News> result = new ListPage<News>();
        HttpSolrServer solrServer = SolrServer.getInstance().getServer();
        SolrQuery sQuery = new SolrQuery();
        
        try {
            String para = this.initKeywordQueryPara(keyword);//初始化para参数方法
            int pageNo=queryParameters.getPageNo();
            int pageSize=queryParameters.getPageSize();
                                                
            sQuery.setStart((pageNo - 1) * pageSize);//设置起始页，类似于sql的分页查询
            sQuery.setRows(pageSize);//设置每页大小，类似于sql的分页查询
            //排序条件
            sQuery.setSort("publishTime", SolrQuery.ORDER.desc); 
            
            sQuery.setQuery(para);//这边的值大概是酱紫的 "* AND publishTime:[1360000 TO 13700000]  AND contentStr:"关键字"";
            QueryResponse response = solrServer.query(sQuery,SolrRequest.METHOD.POST);
            SolrDocumentList list = response.getResults();//response.getResults()返回的类型是SolrDocumentList，solr文档集，所以用它来接收
            Integer counts = (int) list.getNumFound();//获取总数，这个可以从solr Admin 管理页面里看出来，当我们去Query时，结果中也有一个numFound的属性
            List<News> newsList = new ArrayList<News>();
            for (SolrDocument solrDocument : list) {
                News news = null;
                String id = (String) solrDocument.getFieldValue("id");//这边是获取solr上有存储的字段，也就是我们在schema.xml文件里配置的field标签的stored属性，=true就会存储在solr服务器上，因为我的schema.xml只配置id的stored=true，所以这边我先通过获取id，在通过id去数据库获取具体的新闻信息
                news = newsDAO.findById(id);
                if(news != null){
                    newsList.add(news);                
                }

            }

            result.setCurrentPageSize(pageSize);
            result.setCurrentPageNo(pageNo);
            result.setTotalCount(counts);
            result.setDataList(newsList);
            return result;
        } catch (SolrServerException e) {
            log.error("查询solr失败", e);
            e.printStackTrace();
        } finally{
            solrServer.shutdown();
            solrServer = null;
        }

        return result;

    }

public String initKeywordQueryPara(Keyword keyword){
        
        String para = "*";
        
        long dataTimeStart = 0;
        long dataTimeEnd = 0; 
        
        if(keyword.getMonitoringBeginTime() != null){
            dataTimeStart = keyword.getMonitoringBeginTime().getTime();
        }
        if(keyword.getMonitoringEndTime() != null){
            Date endTime = DateUtil.getNextDayCurrDay(keyword.getMonitoringEndTime(), 1);
            dataTimeEnd = endTime.getTime();
        }
        para = para + " AND publishTime:["
        + (dataTimeStart == 0 ? "*" : dataTimeStart) + " TO "
        + (dataTimeEnd == 0 ? "*" : dataTimeEnd) + "]";
        
        String keywords = keyword.getKeywordName();
        if(keywords !=null && keywords.length() > 0){
            String[] targetArr = keywords.split("，");
            para = para + " AND (";
            for (int i = 0; i < targetArr.length; i++) {
                if (i != 0) {
                    para = para + " OR ";
                }
                para = para + "contentStr:"" + targetArr[i] + """;
            }
            para = para + ")";    
        
        }return para;
    }