ES查询结果全局高亮

旧城等待， 2024-04-17 06:14 34阅读 0赞

### 一、功能需求 ###

> 当我们用ES查询到结果后，想对命中关键词的实体的多个字段自动高亮，应该如何实现呢？

需要实现这个功能,大概分为以下几个步骤:

### 二、实现步骤 ###

1.  构造查询方法，设置高亮(`SearchHits方法`)
    
        /**
             * 查询条件构造方法
             *
             * @param indices 索引名称(需要从那个索引当中查询)
             * @param req     查询条件
             * @param fields  查询的文档(对应数据库的字段)
             * @return SearchHit
             */
            public SearchHits queryBuilder(String indices, SearchREQ req, String[] fields) throws IOException {
              
                SearchSourceBuilder builder = new SearchSourceBuilder();
                BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
                HighlightBuilder highlightBuilder = new HighlightBuilder();
        
                //设置分页
                if (req.getCurrent() > 0) {
              
                    builder.from((int) req.getCurrent());
                }
                if (req.getSize() > 0) {
              
                    builder.size((int) req.getSize());
                }
        
                //设置高亮
                highlightBuilder.field("*"); //所有的字段都高亮
                highlightBuilder.requireFieldMatch(false);//如果要多个字段高亮,这项要为false
                highlightBuilder.preTags("<font color='red'>").postTags("</font'>")
                                .fragmentSize(800000)//下面这两项,如果你要高亮如文字内容等有很多字的字段,必须配置,不然会导致高亮不全,文章内容缺失等;  最大高亮分片数
                                .numOfFragments(0);//从第一个分片获取高亮片段
                builder.highlighter(highlightBuilder);
        
        		//构建查询条件
                if (StringUtils.isNotEmpty(req.getUserId())) {
              
                    boolQueryBuilder.must(QueryBuilders.matchQuery("userId", req.getUserId()));
                }
        		//模糊查询
                boolQueryBuilder.should(QueryBuilders.multiMatchQuery("*" + req.getText() + "*", fields));
                //对查询结果进行排序
                builder.query(boolQueryBuilder).sort("createDate", SortOrder.DESC);
        
                SearchRequest searchRequest = new SearchRequest(indices);
                searchRequest.source(builder);
                SearchResponse searchResponse = levelClientTests.search(searchRequest, RequestOptions.DEFAULT);
                return searchResponse.getHits();
            }
2.  调用查询方法，查询结果(`findObject`方法)
    
        public Result findObject(SearchREQ req) throws IOException, 
                  NoSuchFieldException {
              
                if (StringUtils.isEmpty(req.getText())) {
              
                    return Result.error("查找内容不能为空");
                }
                List<Object> resultList = null;
                Map<Object, Object> resultMap = new HashMap<>();
                SearchHits hits;
                String indices = "mcb_article";
                String[] fields = {
              "summary", "title", "mdContent"};
                hits = queryBuilder(indices, req, fields);
                Article article = null;
                resultList = new ArrayList<>();
                //遍历查询结果并接收
                 for (SearchHit searchHit : hits) {
              
                        article = (Article) replaceAttr(searchHit, fields, indices);
                        if (article != null) {
              
                            resultList.add(article);
                        }
                    }
            }
3.  使用工具替换实体的属性值(`replaceAttr`方法)
    
        /**
             * 替换高亮属性
             *
             * @param searchHit 查询结果
             * @param attrs 字段名
             * @return
             * @throws JsonProcessingException
             * @throws NoSuchFieldException
             */
            private Object replaceAttr(SearchHit searchHit, String[] attrs) throws JsonProcessingException, NoSuchFieldException {
              
                
                ObjectMapper objectMapper = new ObjectMapper();
                EntityUtil util = new EntityUtil();
                Object o = null;
                Article article = new Article();
        
                for (String field : attrs) {
              
                    Map<String, HighlightField> highlightFields = searchHit.getHighlightFields();
                    HighlightField hField = highlightFields.get(field);
                    if (hField != null) {
              
                        //替换高亮字段
                        Text[] fragments = hField.fragments();
                        StringBuilder text = new StringBuilder();
                        for (Text textGet : fragments) {
              
                            text.append(textGet);
                        }
                            //对象的值只能读一次,否则会被覆盖
                        if (article.getId() == null) {
              
                            article = objectMapper.readValue(searchHit.
                                      getSourceAsString(), article.getClass());
                        }
                          //设置对象的属性值
                       util.setValue(article, Article.class,field,
                             Article.class.getDeclaredField(field).getType(),text.toString());
                            o = article;
                            continue;
                        }
                }
               return o;
            }
4.  设置对象的属性值()
    
        /**
         * 实体工具
         * @author MyLover
         * @date 2022.2.6
         * @version 1.0.0
         */
        public class EntityUtil {
              
        
            /**
             * 设置对象对应的属性值
             * @param obj 传入的对象
             * @param clazz 传入对象的类
             * @param filedName 需要设置的字段名
             * @param typeClass 字段的类型
             * @param value 需要设置的值
             *  实例:  设置Article的id属性值为1
             *  Article article = new Article();
             *  String field = "id";
             *  setValue(article_es1,Article_ES.class,field,
             *  Article.class.getDeclaredField(field).getType(),"1");
             */
            public void setValue(Object obj, Class<?> clazz, String filedName, Class<?> typeClass, Object value) {
              
                String methodName = "set" + filedName.substring(0, 1)
                    .toUpperCase() + filedName.substring(1);
                try {
              
                    Method method = clazz.getDeclaredMethod(methodName, typeClass);
                    method.invoke(obj, getClassTypeValue(typeClass, value));
                } catch (Exception ex) {
              
                    ex.printStackTrace();
                }
            }
            /**
             * 根据属性，获取对象的属性值, 例如: getGetMethod(Article,id)
             * @param ob   对象
             * @param name 属性名
             */
            public  Object getGetMethod(Object ob, String name) throws Exception {
              
                Method[] m = ob.getClass().getMethods();
                for (Method method : m) {
              
                    if (("get" + name).toLowerCase().equals(method.getName().toLowerCase())) {
              
                        return method.invoke(ob);
                    }
                }
                return null;
            }
        
            private  Object getClassTypeValue(Class<?> typeClass, Object value) {
              
                if (typeClass == int.class || value instanceof Integer) {
              
                    if (null == value) {
              
                        return 0;
                    }
                    return value;
                } else if (typeClass == short.class) {
              
                    if (null == value) {
              
                        return 0;
                    }
                    return value;
                } else if (typeClass == byte.class) {
              
                    if (null == value) {
              
                        return 0;
                    }
                    return value;
                } else if (typeClass == double.class) {
              
                    if (null == value) {
              
                        return 0;
                    }
                    return value;
                } else if (typeClass == long.class) {
              
                    if (null == value) {
              
                        return 0;
                    }
                    return value;
                } else if (typeClass == String.class) {
              
                    if (null == value) {
              
                        return "";
                    }
                    return value;
                } else if (typeClass == boolean.class) {
              
                    if (null == value) {
              
                        return true;
                    }
                    return value;
                } else if (typeClass == BigDecimal.class) {
              
                    if (null == value) {
              
                        return new BigDecimal(0);
                    }
                    return new BigDecimal(value + "");
                } else {
              
                    return typeClass.cast(value);
                }
            }
        }