java基础之----elasticsearch（Java客服端搜索实例）

Posted 2021-03-05 猿起缘灭

 

概述

es是使用Java编写的，对Java原生比较支持，下面是使用Java写的一个demo，根据关键字进行搜索，并对搜索结果重排序，对部分字段惊醒高亮处理。

 

public class EsIndexService { 
    protected Logger logger = LoggerFactory.getLogger(getClass());

    public static final String SCS_WEB_INDEX = "scs_web";
    public static final String QUESTION_TYPE = "question";
    public static final String QUESTION_PAIR_TYPE = "question_pair";
    public static final String DELETED_FLAG = "1";
    public static final String FIELD_CONTENT = "content";
    public static final String FIELD_ANSWER = "answer";
    public static final String FIELD_HRELATION_TYPE = "hRelation.relationType";
    public static final String FIELD_MRELATION_TYPE = "mRelation.relationType";
    public static final String FIELD_QUESTION1_ID = "question1.id";
    public static final String FIELD_QUESTION2_ID = "question2.id";
    public static final String FIELD_HRELATION_START_DATE = "hRelation.startDate";
    public static final String FIELD_HRELATION_EXPIRE_DATE = "hRelation.expireDate";
    public static final String FIELD_SCORE = "score";
    public static final String FIELD_COUNT = "count";
    public static final Float COUNT_FACTOR = 0.1f;

    @Autowired
    private QuestionDao questionDao;

    @Autowired
    private QuestionPairDao questionPairDao;

    @Autowired
    private DataSourceTransactionManager transactionManager;

    @Autowired
    private SearchLogDao searchLogDao;

    public Page<QuestionSearchResult> searchQuestion(Question question) throws IOException {

        //搜索问题为空直接返回
        if (StringUtils.isEmpty(question.getContent())) return emptyResult(question);
　　　　  //es原始搜索
        MatchQueryBuilder matchQueryBuilder = QueryBuilders.matchQuery(FIELD_CONTENT, question.getContent());
　　　　　//开启模糊匹配
        matchQueryBuilder.fuzziness(Fuzziness.AUTO);
        //对原始结果进行重排序，采用的公式为newScore = oldScore + log(1 + 0.1*count),启动count为数据库中一个字段，意思是点击次数，这个优化的目的就是让点击数大的排在前面
        ScoreFunctionBuilder scoreFunctionBuilder = ScoreFunctionBuilders.
                fieldValueFactorFunction(FIELD_COUNT).factor(COUNT_FACTOR).modifier(FieldValueFactorFunction.Modifier.LOG1P);
        FunctionScoreQueryBuilder queryBuilder = QueryBuilders.functionScoreQuery(matchQueryBuilder, scoreFunctionBuilder);
　　　　　//这个就是采用oldScore + log(1 + 0.1*count)，控制中间的加号的，默认是multiply，就是相乘
        queryBuilder.boostMode(CombineFunction.SUM);
        return searchQuestion(question, queryBuilder, null, null);
    }

    public Page<QuestionSearchResult> topByCount(Question question) throws IOException {
        return searchQuestion(question, null, FIELD_COUNT, SortOrder.DESC);
    }

    public Page<QuestionSearchResult> searchQuestion(Question question, QueryBuilder queryBuilder, String orderBy, SortOrder order) throws IOException {

        Page<QuestionSearchResult> resultPage = emptyResult(question);
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.trackScores(true);
        //进行分页的操作，这个是设置每页的大小
        searchSourceBuilder.size(question.getPage().getPageSize());
        if (question.getPage().getPageNo() > 1) {
            //设置从哪里开始搜索
            searchSourceBuilder.from((question.getPage().getPageNo() - 1) * question.getPage().getPageSize());
        }

        if (queryBuilder != null) searchSourceBuilder.query(queryBuilder);
        if (StringUtils.isNotEmpty(orderBy)) searchSourceBuilder.sort(orderBy, order);

      //高亮
        HighlightBuilder highlightBuilder = new HighlightBuilder();
       //高亮的结果会使用<em>中间是需要高亮的数据</em>括住
        highlightBuilder.field(FIELD_CONTENT).field(FIELD_ANSWER).requireFieldMatch(false);
        searchSourceBuilder.highlighter(highlightBuilder);
        
        SearchRequest searchRequest = new SearchRequest(SCS_WEB_INDEX);
        searchRequest.types(QUESTION_TYPE);
        searchRequest.source(searchSourceBuilder);

        SearchResponse response = EsUtil.client.search(searchRequest);
        logger.info("搜索问题[{}]，结果：{}条，最高score：{}，耗时：{}ms",
                question.getContent(), response.getHits().totalHits,
                response.getHits().getMaxScore(), response.getTookInMillis());
        int maxResultCount = Integer.parseInt(DictUtils.getDictValue("max_result_count", "scs_config", "30"));
        resultPage.setCount(response.getHits().totalHits > maxResultCount ? maxResultCount : response.getHits().totalHits);
        if (response.getHits().totalHits < 1) {
            return resultPage;
        }
        BigDecimal maxScore = BigDecimal.valueOf(response.getHits().getMaxScore());
        for (SearchHit hit : response.getHits()) {
            QuestionSearchResult tmp = new QuestionSearchResult();
            tmp.setSimilarQuestion((Question) JsonMapper.fromJsonString(hit.getSourceAsString(), Question.class));
            BigDecimal currentDocScore = BigDecimal.valueOf(hit.getScore());
            tmp.setEsScore(currentDocScore.divide(maxScore, 4, BigDecimal.ROUND_HALF_EVEN));
            logger.debug("搜索结果 score: {}, question: {}, count：{}, id: {}",
                    hit.getScore(), tmp.getSimilarQuestion().getContent(), tmp.getSimilarQuestion().getCount(), hit.getId());
            List<StringHighlightField> highlightList = new ArrayList<>();
            for (String key : hit.getHighlightFields().keySet()) {
                highlightList.add(StringHighlightField.fromHighlightField(hit.getHighlightFields().get(key)));
            }
            tmp.setHighlightList(highlightList);
            resultPage.getList().add(tmp);
        }
        searchLogDao.insert(question.getContent(), response.getHits().getTotalHits());
        return resultPage;

    }