Elasticsearch简单的使用步骤

1）搭建ES服务器（单机、集群）
2）创建映射，建立实体和索引库的映射关系，使用spring-data-elasticsearch
　　//ES提供的接口，可以对索引库进行CRUD操作；T建立了和索引库映射关系的对象、ID为T对象中的主键类型
　　ElasticsearchRepository<T,ID>

　　//操作索引库
　　ElasticSearchTemplate
3）索引库维护（初始化数据导入全量索引、增量索引、索引同步、定时索引(全量索引、增量索引)，手动索引）

RestHighLevelClient实现搜索

//RestHighLevelClient实现搜索功能
//3个重要查询对象SearchRequest、SearchSourceBuilder（排序、分页、高亮、分组）、BoolQueryBuilder
@Autowired
private RestHighLevelClient restHighLevelClient;//准备工作，注入RestHighLevelClient
public Map search(Map<String,String> searchMap) {
 //1.封装查询请求，指定“索引库”，“类型”
 SearchRequest searchRequest=new SearchRequest("sku");
 searchRequest.types("doc"); //设置查询的类型
 SearchSourceBuilder searchSourceBuilder=new SearchSourceBuilder();
 BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();//布尔查询构建器
 //1.1 关键字搜索
    if (StringUtils.isNotEmpty(searchMap.get("keywords"))){
  boolQueryBuilder.must(QueryBuilders.matchQuery("name",searchMap.get("keywords"));
   }
 //1.2 静态过滤，key固定
 if(searchMap.get("category")!=null){
  boolQueryBuilder.filter(QueryBuilders.termQuery("categoryName", searchMap.get("category"));
 }
 //1.4 动态过滤，key是拼接后得到
 for(String key: searchMap.keySet() ){
  if( key.startsWith("spec.") ){//如果是规格参数
   TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery(key+".keyword", searchMap.get(key));
   boolQueryBuilder.filter(termQueryBuilder);
  }
 }
 //1.5 数值区间过滤
 if(searchMap.get("price")!=null ){
  String[] price = searchMap.get("price").split("-");
  if (prices.length == 2){
             boolQueryBuilder.filter(QueryBuilders.rangeQuery("price").lte(prices[1]));
       }
        boolQueryBuilder.filter(QueryBuilders.rangeQuery("price").gte(prices[0]));
 }
 searchSourceBuilder.query(boolQueryBuilder);
 //分页
 searchSourceBuilder.from(fromIndex);//开始索引设置
 searchSourceBuilder.size(pageSize);//每页记录数设置
 //排序 
 searchSourceBuilder.sort("排序的域", "顺序DESC|ASC");
 //高亮设置
 HighlightBuilder highlightBuilder=new HighlightBuilder();
 highlightBuilder.field("name").preTags("<font style='color:red'>").postTags("</font>");
 searchSourceBuilder.highlighter(highlightBuilder);
 searchRequest.source(searchSourceBuilder);
 //聚合查询（商品分类）
 TermsAggregationBuilder termsAggregationBuilder = AggregationBuilders.terms("sku_category").field("categoryName");
 searchSourceBuilder.aggregation(termsAggregationBuilder);
 //2.封装查询结果
 Map resultMap=new HashMap();
 try {
  SearchResponse searchResponse  = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
  SearchHits searchHits = searchResponse.getHits();
  long totalHits = searchHits.getTotalHits();
  System.out.println("记录数："+totalHits);
  SearchHit[] hits = searchHits.getHits();
​
  //2.1 商品列表
  List<Map<String,Object>> resultList=new ArrayList<Map<String, Object>>();
  for(SearchHit hit:hits){
   Map<String, Object> skuMap = hit.getSourceAsMap();
   //name高亮处理
   Map<String, HighlightField> highlightFields = hit.getHighlightFields();
   HighlightField name = highlightFields.get("name");
   Text[] fragments = name.fragments();
   skuMap.put("name",fragments[0].toString());//用高亮的内容替换原内容
   resultList.add(skuMap);
  }
  resultMap.put("rows",resultList);
  //2.2 商品分类列表
  Aggregations aggregations = searchResponse.getAggregations();
  Map<String, Aggregation> aggregationMap = aggregations.getAsMap();
  Terms terms = (Terms) aggregationMap.get("sku_category");
  List<? extends Terms.Bucket> buckets =  terms.getBuckets();
  List<String> categoryList=new ArrayList();
  for( Terms.Bucket bucket:buckets ){
   categoryList.add(bucket.getKeyAsString());
 }
resultMap.put("categoryList",categoryList);
String categoryName = "";//商品分类名称
if (searchMap.get("category") == null) { // 如果没有分类条件
if (categoryList.size() > 0) {
categoryName = categoryList.get(0);//提取分类列表的第一个分类
 }
 } else {
categoryName = searchMap.get("category");//取出参数中的分类
 }
//2.3 品牌列表
if(searchMap.get("brand")==null) {
List<Map> brandList = brandMapper.findListByCategoryName(categoryName);//查询品牌列表
resultMap.put("brandList", brandList);
 }
​
//2.4 规格列表
List<Map> specList = specMapper.findListByCategoryName(categoryName);//规格列表
for(Map spec:specList){
String[] options = ((String) spec.get("options")).split(",");//规格选项列表
spec.put("options",options);
 }
resultMap.put("specList",specList);
​
//2.5 页码
long totalCount = searchHits.getTotalHits();  //总记录数
long pageCount = (totalCount%pageSize==0 )?totalCount/pageSize:(totalCount/pageSize+1);//总页数
resultMap.put("totalPages",pageCount);
​
 } catch (IOException e) {
e.printStackTrace();
 }
return resultMap;
}

ElasticsearchTemplate实现搜索

//ElasticsearchTemplate(Sring-data-ElasticSearch)实现搜索功能
@Autowired
private ElasticsearchTemplate elasticsearchTemplate;//准备工作，注入ElasticsearchTemplate
//(1)构建搜索条件对象NativeSearchQueryBuilder:SearchRequest+SearchSourceBuilder
NativeSearchQueryBuilder nativeSearchQueryBuilder = new NativeSearchQueryBuilder();
//(2)构建多条件拼接查询对象BoolQueryBuilder
BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
//(3)往多条件拼接条件对象BoolQueryBuilder中添加条件
//boolQuery.must|should|mustNot|filter(QueryBuilders.xxxx)
    //xxxx表示查询类型，例如：term、match、range（正则、模糊、前后缀）
...????...//其它条件省略
//(4)多条件查询对象BoolQueryBuilder,放入整理查询对象中
nativeSearchQueryBuilder.withQuery(boolQuery);
//(5)使用NativeSearchQueryBuilder设置分组、分页、排序、高亮查询条件
//nativeSearchQueryBuilder.addAggregation|withPageable|withSort|withHighlightFields
...????...
//(6)获取查询结果“页面展示数据结果集--->‘高亮结果集’”、“搜索面板条件数据”、“分页数据”
AggregatedPage<SkuInfo> resultInfo = elasticsearchTemplate.queryForPage(nativeSearchQueryBuilder.build(), SkuInfo.class, new SearchResultMapper() {
 @Override
 public <T> AggregatedPage<T> mapResults(SearchResponse searchResponse, Class<T> aClass, Pageable pageable) {
  //1.查询“页面展示数据结果集--->‘高亮结果集’”
  List<T> list = new ArrayList<>();
  //获取查询命中结果数据
  SearchHits hits = searchResponse.getHits();
  if (hits != null){
   //有查询结果
   for (SearchHit hit : hits) {
    //SearchHit转换为skuinfo
    SkuInfo skuInfo = JSON.parseObject(hit.getSourceAsString(), SkuInfo.class);
                //获取高亮数据，封装到”页面展示数据结果集“中
    Map<String, HighlightField> highlightFields = hit.getHighlightFields();
    if (highlightFields != null && highlightFields.size()>0){
     //替换数据
     skuInfo.setName(highlightFields.get("name").getFragments()[0].toString());
    }
    list.add((T) skuInfo);
   }
  }
  return new AggregatedPageImpl<T>(list,pageable,hits.getTotalHits(),searchResponse.getAggregations());
 }
});
//2.“搜索面板条件数据”，分组查询结果
//封装品牌的分组结果
StringTerms brandTerms = (StringTerms) resultInfo.getAggregation(skuBrand);
List<String> brandList = brandTerms.getBuckets().stream().map(bucket -> bucket.getKeyAsString()).collect(Collectors.toList());
//封装规格分组结果
StringTerms specTerms= (StringTerms) resultInfo.getAggregation(skuSpec);
List<String> specList = specTerms.getBuckets().stream().map(bucket -> bucket.getKeyAsString()).collect(Collectors.toList());
//3.“分页数据”
long total = resultInfo.getTotalElements();//总条数
int totalPages = resultInfo.getTotalPages()//总页数
//4.查询结果封装
Map<String,Object> resultMap = new HashMap<>();
//总记录数
resultMap.put("total",resultInfo.getTotalElements());
//总页数
resultMap.put("totalPages",resultInfo.getTotalPages());
//数据集合
resultMap.put("rows",resultInfo.getContent());
//搜索面板-品牌列表
resultMap.put("brandList",brandList);
//搜索面板-规格列表
resultMap.put("specList",this.formartSpec(specList));
//搜索条件数据回显（定义在controller层进行返回）