简易论坛–全文搜索

1、思路

2、使用技术或方法

mybatis,依赖注入，SpringMVC，MVC,thymeleaf,Elasticsearch

3、关键代码

3.1、关键类

ElasticsearchTemplate

/*** 该类使用了ES建立索引,并对应*/
//shards：分片数，replicas:副本数
@Document(indexName = "discusspost",type = "_doc",shards =6 ,replicas =3 )
public class DiscussPost {@Idprivate int id;@Field(type = FieldType.Integer)private int userId;//analyzer存储时候的解析器,searchAnalyzer是搜索时候的解析器//analyzer = "ik_max_word"表示以分解最多的词语与本句匹配//searchAnalyzer = "ik_smart"表示搜索的时候尽可能的满足需求@Field(type = FieldType.Text,analyzer = "ik_max_word",searchAnalyzer = "ik_smart")private String title;@Field(type = FieldType.Text,analyzer = "ik_max_word",searchAnalyzer = "ik_smart")private String content;@Field(type = FieldType.Integer)private int type;@Field(type = FieldType.Integer)private int status;@Field(type = FieldType.Date)private Date createTime;@Field(type = FieldType.Integer)private int commentCount;@Field(type = FieldType.Double)private double score;public int getId() {return id;}public void setId(int id) {this.id = id;}public int getUserId() {return userId;}public void setUserId(int userId) {this.userId = userId;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getContent() {return content;}public void setContent(String content) {this.content = content;}public int getType() {return type;}public void setType(int type) {this.type = type;}public int getStatus() {return status;}public void setStatus(int status) {this.status = status;}public Date getCreateTime() {return createTime;}public void setCreateTime(Date createTime) {this.createTime = createTime;}public int getCommentCount() {return commentCount;}public void setCommentCount(int commentCount) {this.commentCount = commentCount;}public double getScore() {return score;}public void setScore(double score) {this.score = score;}@Overridepublic String toString() {return "DiscussPost{" +"id=" + id +", userId=" + userId +", title='" + title + '\'' +", content='" + content + '\'' +", type=" + type +", status=" + status +", createTime=" + createTime +", commentCount=" + commentCount +", score=" + score +'}';}
}

3.2、关键逻辑

 @Testpublic void testSearchByRepository() {SearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(QueryBuilders.multiMatchQuery("互联网寒冬", "title", "content"))//构建搜索条件.withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC))//构建排序规则.withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC)).withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC)).withPageable(PageRequest.of(0, 10))//构建分页条件.withHighlightFields(//对哪些字段高亮显示new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")).build();// 底层调用了elasticTemplate.queryForPage(searchQuery, class, SearchResultMapper)// 底层获取得到了高亮显示的值, 但是没有返回.//es返回的结果只是匹配的一段，而不是所有Page<DiscussPost> page = discussRepository.search(searchQuery);System.out.println(page.getTotalElements());System.out.println(page.getTotalPages());System.out.println(page.getNumber());System.out.println(page.getSize());for (DiscussPost post : page) {System.out.println(post);}}

 @Testpublic void testSearchByTemplate() {SearchQuery searchQuery = new NativeSearchQueryBuilder().withQuery(QueryBuilders.multiMatchQuery("互联网寒冬", "title", "content")).withSort(SortBuilders.fieldSort("type").order(SortOrder.DESC)).withSort(SortBuilders.fieldSort("score").order(SortOrder.DESC)).withSort(SortBuilders.fieldSort("createTime").order(SortOrder.DESC)).withPageable(PageRequest.of(0, 10)).withHighlightFields(new HighlightBuilder.Field("title").preTags("<em>").postTags("</em>"),new HighlightBuilder.Field("content").preTags("<em>").postTags("</em>")).build();Page<DiscussPost> page = elasticTemplate.queryForPage(searchQuery, DiscussPost.class, new SearchResultMapper() {@Overridepublic <T> AggregatedPage<T> mapResults(SearchResponse response, Class<T> aClass, Pageable pageable) {//queryForPage获得的结果会由Mapper去处理，而这个处理的结果可以由response获取到//得到命中的数据SearchHits hits = response.getHits();if (hits.getTotalHits() <= 0) {return null;}List<DiscussPost> list = new ArrayList<>();for (SearchHit hit : hits) {DiscussPost post = new DiscussPost();//getSourceAsMap返回map类型的数据String id = hit.getSourceAsMap().get("id").toString();post.setId(Integer.valueOf(id));String userId = hit.getSourceAsMap().get("userId").toString();post.setUserId(Integer.valueOf(userId));String title = hit.getSourceAsMap().get("title").toString();post.setTitle(title);String content = hit.getSourceAsMap().get("content").toString();post.setContent(content);String status = hit.getSourceAsMap().get("status").toString();post.setStatus(Integer.valueOf(status));String createTime = hit.getSourceAsMap().get("createTime").toString();post.setCreateTime(new Date(Long.valueOf(createTime)));String commentCount = hit.getSourceAsMap().get("commentCount").toString();post.setCommentCount(Integer.valueOf(commentCount));// 处理高亮显示的结果HighlightField titleField = hit.getHighlightFields().get("title");if (titleField != null) {//getFragments返回的是一个数组post.setTitle(titleField.getFragments()[0].toString());}HighlightField contentField = hit.getHighlightFields().get("content");if (contentField != null) {post.setContent(contentField.getFragments()[0].toString());}list.add(post);}//return new AggregatedPageImpl(list, pageable,hits.getTotalHits(), response.getAggregations(), response.getScrollId(), hits.getMaxScore());}@Overridepublic <T> T mapSearchHit(SearchHit searchHit, Class<T> aClass) {return null;}});System.out.println(page.getTotalElements());System.out.println(page.getTotalPages());System.out.println(page.getNumber());System.out.println(page.getSize());for (DiscussPost post : page) {System.out.println(post);}}

4、扩展

Elasticsearch简介

• 一个分布式的、Restful风格（是一种设计风格，规定前后端以按照什么标准进行交互）的搜索引擎。
• 支持对各种类型的数据的检索。
• 搜索速度快，可以提供实时的搜索服务。
• 便于水平扩展，每秒可以处理PB级海量数据。

Elasticsearch术语
-索引（相当于一张表），类型（7.0之后逐渐废弃），文档（一条或一行数据，一般用JSON类型），字段（相当于MySQL的列）
-集群，节点，分片（对索引进行划分，提高并发能力），副本（对分片的备份）

Spring整合Elasticsearch

引入依赖

• spring-boot-starter-data-elasticsearch

配置Elasticsearch

• cluster-name、cluster-nodes

Spring Data Elasticsearch

• ElasticsearchTemplate
• ElasticsearchRepository

5、注意点

6、后续优化

6.1、优化思路

6.2、优化点