七、IK分词器
ElasticSearch中采用标准分词器进行分词，这种方式并不适用于中文网站。因此需要修改ElasticSearch对中文友好分词，从而达到更佳的搜索的效果。而支持中文分词的分词器就是IK分词器。
7.1、在线安装IK分词器
将ElasticSearch服务中原始数据删除（必做）
# 进入es安装目录中将data目录数据删除 rm -rf data 复制代码
安装IK分词器
# 在es安装目录中执行 ./bin/elasticsearch-plugin install https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v6.8.0/elasticsearch-analysis-ik-6.8.0.zip 复制代码
IK分词器要求版本严格与当前使用版本一致，如需使用其他版本替换 6.2.4 为使用的版本号。
测试
GET /_analyze { "text": "中华人民共和国国歌", "analyzer": "ik_smart" } 复制代码
7.2、离线安装IK分词器
可以将对应的IK分词器下载到本地,然后再安装，官网下载地址：官网直达，下面贴一张官网给的IK分词器和ElasticSearch版本对应图。
去官网下载对应版本的IK分词器
# 可以去官网下载然后上传，或者使用wegt命令，下载其他版本的修改版本号即可。 wget https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v6.2.4/elasticsearch-analysis-ik-6.2.4.zip 复制代码
解压
unzip elasticsearch-analysis-ik-6.2.4.zip 复制代码
移动到es安装目录的plugins目录中
mv elasticsearch elasticsearch-6.2.4/plugins/ 复制代码
重启ElasticSearch生效
本地安装ik分词器配置目录：es安装目录中/plugins/analysis-ik/config/IKAnalyzer.cfg.xml
测试
DELETE /ems PUT /ems { "mappings":{ "emp":{ "properties":{ "name":{ "type":"text", "analyzer": "ik_max_word", "search_analyzer": "ik_max_word" }, "age":{ "type":"integer" }, "bir":{ "type":"date" }, "content":{ "type":"text", "analyzer": "ik_max_word", "search_analyzer": "ik_max_word" }, "address":{ "type":"keyword" } } } } } PUT /ems/emp/_bulk {"index":{}} {"name":"小黑","age":23,"bir":"2012-12-12","content":"为开发团队选择一款优秀的MVC框架是件难事儿，在众多可行的方案中决择需要很高的经验和水平","address":"北京"} {"index":{}} {"name":"王小黑","age":24,"bir":"2012-12-12","content":"Spring 框架是一个分层架构，由 7 个定义良好的模块组成。Spring 模块构建在核心容器之上，核心容器定义了创建、配置和管理 bean 的方式","address":"上海"} {"index":{}} {"name":"张小五","age":8,"bir":"2012-12-12","content":"Spring Cloud 作为Java 语言的微服务框架，它依赖于Spring Boot，有快速开发、持续交付和容易部署等特点。Spring Cloud 的组件非常多，涉及微服务的方方面面，井在开源社区Spring 和Netflix 、Pivotal 两大公司的推动下越来越完善","address":"无锡"} {"index":{}} {"name":"win7","age":9,"bir":"2012-12-12","content":"Spring的目标是致力于全方位的简化Java开发。 这势必引出更多的解释， Spring是如何简化Java开发的？","address":"南京"} {"index":{}} {"name":"梅超风","age":43,"bir":"2012-12-12","content":"Redis是一个开源的使用ANSI C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库，并提供多种语言的API","address":"杭州"} {"index":{}} {"name":"张无忌","age":59,"bir":"2012-12-12","content":"ElasticSearch是一个基于Lucene的搜索服务器。它提供了一个分布式多用户能力的全文搜索引擎，基于RESTful web接口","address":"北京"} GET /ems/emp/_search { "query":{ "term":{ "content":"框架" } }, "highlight": { "pre_tags": ["<span style='color:red'>"], "post_tags": ["</span>"], "fields": { "*":{} } } } 复制代码
7.3、IK分词器的类型
7.3.1、ik_max_word
ik_max_word：会将文本做最细粒度的拆分，比如会将“中华人民共和国国歌”拆分为“中华人民共和国,中华人民,中华,华人,人民共和国,人民,人,民,共和国,共和,和,国国,国歌”，会穷尽各种可能的组合。
7.3.2、ik_smart
ik_smart：会做最粗粒度的拆分，比如会将“中华人民共和国国歌”拆分为“中华人民共和国,国歌”。
7.4、配置扩展词
IK支持自定义扩展词典和停用词典，所谓**扩展词典就是有些词并不是关键词,但是也希望被ES用来作为检索的关键词，可以将这些词加入扩展词典。停用词典**就是有些词是关键词,但是出于业务场景不想使用这些关键词被检索到，可以将这些词放入停用词典。词典的编码必须为UTF-8，否则无法生效。
定义扩展词典和停用词典可以修改IK分词器中config目录中IKAnalyzer.cfg.xml这个文件。
修改IKAnalyzer.cfg.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd"> <properties> <comment>IK Analyzer 扩展配置</comment> <!--用户可以在这里配置自己的扩展字典 --> <entry key="ext_dict">ext_dict.dic</entry> <!--用户可以在这里配置自己的扩展停止词字典--> <entry key="ext_stopwords">ext_stopword.dic</entry> </properties> 复制代码
在ik分词器目录下config目录中创建ext_dict.dic文件
编码一定要为UTF-8才能生效。
在ext_dict.dic中加入扩展词即可
重启ElasticSearch生效
八、Filter Query过滤查询
8.1、过滤查询
其实准确来说，ElasticSearch中的查询操作分为2种:
- 查询(query)：查询即是之前提到的query查询，它 (查询)默认会计算每个返回文档的得分，然后根据得分排序。
- 过滤(filter)：过滤(filter)只会筛选出符合的文档，并不计算得分，且它可以缓存文档 。
所以，单从性能考虑，过滤比查询更快。
过滤适合在大范围筛选数据，而查询则适合精确匹配数据。一般应用时， 应先使用过滤操作过滤数据， 然后使用查询匹配数据。
8.2、过滤语法
GET /ems/emp/_search { "query": { "bool": { "must": [ {"match_all": {}} ], "filter": { "range": { "age": { "gte": 10 } } } } } } 复制代码
在执行filter和query时，先执行filter再执行query。Elasticsearch会自动缓存经常使用的过滤器，以加快性能。
8.3、过滤器类型
8.3.1、term
GET /ems/emp/_search # 使用term过滤 { "query": { "bool": { "must": [ {"term": { "name": { "value": "小黑" } }} ], "filter": { "term": { "content":"框架" } } } } } 复制代码
8.3.2、terms
GET /dangdang/book/_search #使用terms过滤 { "query": { "bool": { "must": [ {"term": { "name": { "value": "中国" } }} ], "filter": { "terms": { "content":[ "科技", "声音" ] } } } } } 复制代码
8.3.3、range
GET /ems/emp/_search { "query": { "bool": { "must": [ {"term": { "name": { "value": "中国" } }} ], "filter": { "range": { "age": { "gte": 7, "lte": 20 } } } } } } 复制代码
8.3.4、exists
过滤存在指定字段,获取字段不为空的索引记录使用
GET /ems/emp/_search { "query": { "bool": { "must": [ {"term": { "name": { "value": "中国" } }} ], "filter": { "exists": { "field":"aaa" } } } } } 复制代码
8.3.5、ids
过滤含有指定字段的索引记录。
GET /ems/emp/_search { "query": { "bool": { "must": [ {"term": { "name": { "value": "中国" } }} ], "filter": { "ids": { "values": ["1","2","3"] } } } } } 复制代码
九、Java操作ElasticSearch
ElasticSearch不能够取代数据库，ElasticSearch最核心最强大的功能时完成检索，可以把给用户查询到的数据放ElasticSearch中
9.1、引入依赖
<dependency> <groupId>org.elasticsearch</groupId> <artifactId>elasticsearch</artifactId> <version>6.8.0</version> </dependency> <dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>transport</artifactId> <version>6.8.0</version> </dependency> <dependency> <groupId>org.elasticsearch.plugin</groupId> <artifactId>transport-netty4-client</artifactId> <version>6.8.0</version> </dependency> 复制代码
9.2、创建索引和类型
PUT /dangdang { "mappings": { "book":{ "properties": { "name":{ "type":"text", "analyzer": "ik_max_word" }, "age":{ "type":"integer" }, "sex":{ "type":"keyword" }, "content":{ "type":"text", "analyzer": "ik_max_word" } } } } } 复制代码
9.3、Java操作ElasticSearch
9.3.1、创建客户端对象
//创建ES客户端操作对象 @Test public void init() throws UnknownHostException { PreBuiltTransportClient preBuiltTransportClient = new PreBuiltTransportClient(Settings.EMPTY); preBuiltTransportClient.addTransportAddress(new TransportAddress( InetAddress.getByName("192.168.202.200"),9300)); } 复制代码
9.3.2、创建索引
//创建索引 @Test public void createIndex() throws UnknownHostException, ExecutionException, InterruptedException { PreBuiltTransportClient preBuiltTransportClient = new PreBuiltTransportClient(Settings.EMPTY); preBuiltTransportClient.addTransportAddress(new TransportAddress( InetAddress.getByName("192.168.202.200"),9300)); //定义索引请求 CreateIndexRequest ems = new CreateIndexRequest("ems"); //执行索引创建 CreateIndexResponse createIndexResponse = preBuiltTransportClient.admin().indices().create(ems).get(); System.out.println(createIndexResponse.isAcknowledged()); } 复制代码
9.3.3、删除索引
//删除索引 @Test public void deleteIndex() throws UnknownHostException, ExecutionException, InterruptedException { PreBuiltTransportClient preBuiltTransportClient = new PreBuiltTransportClient(Settings.EMPTY); preBuiltTransportClient.addTransportAddress(new TransportAddress( InetAddress.getByName("192.168.202.200"),9300)); //定义索引请求 DeleteIndexRequest ems = new DeleteIndexRequest("ems"); //执行索引删除 AcknowledgedResponse acknowledgedResponse = preBuiltTransportClient.admin().indices().delete(ems).get(); System.out.println(acknowledgedResponse.isAcknowledged()); } 复制代码
9.3.4、创建索引和类型
//创建索引类型和映射 @Test public void init() throws UnknownHostException, ExecutionException, InterruptedException { PreBuiltTransportClient preBuiltTransportClient = new PreBuiltTransportClient(Settings.EMPTY); preBuiltTransportClient.addTransportAddress(new TransportAddress( InetAddress.getByName("192.168.202.200"),9300)); //创建索引 CreateIndexRequest ems = new CreateIndexRequest("ems"); //定义json格式映射 String json = "{\"properties\":{\"name\":{\"type\":\"text\",\"analyzer\":\"ik_max_word\"},\"age\":{\"type\":\"integer\"},\"sex\":{\"type\":\"keyword\"},\"content\":{\"type\":\"text\",\"analyzer\":\"ik_max_word\"}}}"; //设置类型和mapping ems.mapping("emp",json, XContentType.JSON); //执行创建 CreateIndexResponse createIndexResponse = preBuiltTransportClient.admin().indices().create(ems).get(); System.out.println(createIndexResponse.isAcknowledged()); } 复制代码
9.3.5、索引一条记录
9.3.5.1、根据id索引
//索引一条文档 指定id @Test public void createIndexOptionId() throws JsonProcessingException { Emp emp = new Emp("xiaolin", 18, "男", "我是xiaolin，来自中国"); String s = JSONObject.toJSONString(emp); IndexResponse indexResponse = transportClient.prepareIndex("ems", "emp", "1").setSource(s, XContentType.JSON).get(); System.out.println(indexResponse.status()); } 复制代码
9.3.5.2、自动生成id索引记录
//索引一条文档 指定id @Test public void createIndexOptionId() throws JsonProcessingException { Emp emp = new Emp("XiaoLin", 18 , "男", "我是XiaoLin"); String s = JSONObject.toJSONString(emp); IndexResponse indexResponse = transportClient.prepareIndex("ems", "emp") .setSource(s, XContentType.JSON).get(); System.out.println(indexResponse.status()); } 复制代码
9.3.6、更新索引
//更新一条记录 @Test public void testUpdate() throws IOException { Emp emp = new Emp(); emp.setName("明天你好"); String s = JSONObject.toJSONString(emp); UpdateResponse updateResponse = transportClient.prepareUpdate("ems", "emp", "1") .setDoc(s,XContentType.JSON).get(); System.out.println(updateResponse.status()); } 复制代码
9.3.6、批量更新
//批量更新 @Test public void testBulk() throws IOException { //添加第一条记录 IndexRequest request1 = new IndexRequest("ems","emp","1"); Emp emp = new Emp("中国科技", 23, "男", "这是好人"); request1.source(JSONObject.toJSONString(emp),XContentType.JSON); //添加第二条记录 IndexRequest request2 = new IndexRequest("ems","emp","2"); Emp emp2 = new Emp("中国科技", 23, "男", "这是好人"); request2.source(JSONObject.toJSONString(emp2),XContentType.JSON); //更新记录 UpdateRequest updateRequest = new UpdateRequest("ems","emp","1"); Emp empUpdate = new Emp(); empUpdate.setName("中国力量"); updateRequest.doc(JSONObject.toJSONString(empUpdate),XContentType.JSON); //删除一条记录 DeleteRequest deleteRequest = new DeleteRequest("ems","emp","2"); BulkResponse bulkItemResponses = transportClient.prepareBulk() .add(request1) .add(request2) .add(updateRequest) .add(deleteRequest) .get(); BulkItemResponse[] items = bulkItemResponses.getItems(); for (BulkItemResponse item : items) { System.out.println(item.status()); } } 复制代码
9.3.7、检索文档
9.3.7.1、查询所有并排序
/** * 查询所有并排序 * ASC 升序 DESC 降序 * addSort("age", SortOrder.ASC) 指定排序字段以及使用哪种方式排序 * addSort("age", SortOrder.DESC) 指定排序字段以及使用哪种方式排序 */ @Test public void testMatchAllQuery() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(QueryBuilders.matchAllQuery()).addSort("age", SortOrder.DESC).get(); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的记录数: "+hits.totalHits); for (SearchHit hit : hits) { System.out.print("当前索引的分数: "+hit.getScore()); System.out.print(", 对应结果:=====>"+hit.getSourceAsString()); System.out.println(", 指定字段结果:"+hit.getSourceAsMap().get("name")); System.out.println("================================================="); } } 复制代码
9.3.7.2、分页查询
/** * 分页查询 * From 从那条记录开始 默认从0 开始 form = (pageNow-1)*size * Size 每次返回多少条符合条件的结果 默认10 */ @Test public void testMatchAllQueryFormAndSize() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(QueryBuilders.matchAllQuery()).setFrom(0).setSize(2).get(); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的记录数: "+hits.totalHits); for (SearchHit hit : hits) { System.out.print("当前索引的分数: "+hit.getScore()); System.out.print(", 对应结果:=====>"+hit.getSourceAsString()); System.out.println(", 指定字段结果:"+hit.getSourceAsMap().get("name")); System.out.println("================================================="); } } 复制代码
9.3.7.3、返回查询字段
/** * 查询返回指定字段(source) 默认返回所有 * setFetchSource 参数1:包含哪些字段 参数2:排除哪些字段 * setFetchSource("*","age") 返回所有字段中排除age字段 * setFetchSource("name","") 只返回name字段 * setFetchSource(new String[]{},new String[]{}) */ @Test public void testMatchAllQuerySource() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(QueryBuilders.matchAllQuery()).setFetchSource("*","age").get(); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的记录数: "+hits.totalHits); for (SearchHit hit : hits) { System.out.print("当前索引的分数: "+hit.getScore()); System.out.print(", 对应结果:=====>"+hit.getSourceAsString()); System.out.println(", 指定字段结果:"+hit.getSourceAsMap().get("name")); System.out.println("================================================="); } } 复制代码
9.3.7.8、term查询
/** * term查询 */ @Test public void testTerm() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); TermQueryBuilder queryBuilder = QueryBuilders.termQuery("name","中国"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(queryBuilder).get(); } 复制代码
9.3.7.9、range查询
/** * rang查询 * lt 小于 * lte 小于等于 * gt 大于 * gte 大于等于 */ @Test public void testRange() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); RangeQueryBuilder rangeQueryBuilder = QueryBuilders.rangeQuery("age").lt(45).gte(8); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(rangeQueryBuilder).get(); } 复制代码
9.3.7.10、prefix查询
/** * prefix 前缀查询 * */ @Test public void testPrefix() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); PrefixQueryBuilder prefixQueryBuilder = QueryBuilders.prefixQuery("name", "中"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(prefixQueryBuilder).get(); } 复制代码
9.3.7.11、wildcard查询
/** * wildcardQuery 通配符查询 * */ @Test public void testwildcardQuery() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); WildcardQueryBuilder wildcardQueryBuilder = QueryBuilders.wildcardQuery("name", "中*"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(wildcardQueryBuilder).get(); } 复制代码
9.3.7.12、ids查询
/** * ids 查询 */ @Test public void testIds() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); IdsQueryBuilder idsQueryBuilder = QueryBuilders.idsQuery().addIds("1","2"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(idsQueryBuilder).get(); } 复制代码
9.3.7.13、fuzzy查询
/** * fuzzy 模糊查询 */ @Test public void testFuzzy() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); FuzzyQueryBuilder fuzzyQueryBuilder = QueryBuilders.fuzzyQuery("content", "国人"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(fuzzyQueryBuilder).get(); } 复制代码
9.3.7.14、bool查询
/** * bool 布尔查询 */ @Test public void testBool() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery(); boolQueryBuilder.should(QueryBuilders.matchAllQuery()); boolQueryBuilder.mustNot(QueryBuilders.rangeQuery("age").lte(8)); boolQueryBuilder.must(QueryBuilders.termQuery("name","中国")); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").setQuery(boolQueryBuilder).get(); } 复制代码
9.3.7.15、高亮查询
/** * 高亮查询 * .highlighter(highlightBuilder) 用来指定高亮设置 * requireFieldMatch(false) 开启多个字段高亮 * field 用来定义高亮字段 * preTags("<span style='color:red'>") 用来指定高亮前缀 * postTags("</span>") 用来指定高亮后缀 */ @Test public void testHighlight() throws UnknownHostException { TransportClient transportClient = new PreBuiltTransportClient(Settings.EMPTY).addTransportAddress(new TransportAddress(InetAddress.getByName("172.16.251.142"), 9300)); TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("name", "中国"); HighlightBuilder highlightBuilder = new HighlightBuilder(); highlightBuilder.requireFieldMatch(false).field("name").field("content").preTags("<span style='color:red'>").postTags("</span>"); SearchResponse searchResponse = transportClient.prepareSearch("dangdang").setTypes("book").highlighter(highlightBuilder).highlighter(highlightBuilder).setQuery(termQueryBuilder).get(); SearchHits hits = searchResponse.getHits(); System.out.println("符合条件的记录数: "+hits.totalHits); for (SearchHit hit : hits) { Map<String, Object> sourceAsMap = hit.getSourceAsMap(); Map<String, HighlightField> highlightFields = hit.getHighlightFields(); System.out.println("================高亮之前=========="); for(Map.Entry<String,Object> entry:sourceAsMap.entrySet()){ System.out.println("key: "+entry.getKey() +" value: "+entry.getValue()); } System.out.println("================高亮之后=========="); for (Map.Entry<String,Object> entry:sourceAsMap.entrySet()){ HighlightField highlightField = highlightFields.get(entry.getKey()); if (highlightField!=null){ System.out.println("key: "+entry.getKey() +" value: "+ highlightField.fragments()[0]); }else{ System.out.println("key: "+entry.getKey() +" value: "+entry.getValue()); } } } }
