安装可视化 kibana  组件

IK分词器

在搜索时，需要对用户输入内容分词。但默认的分词规则对中文处理并不友好。

在kibana 的 DevTools 中测试

<properties>
<java.version>1.8</java.version>
<elasticsearch.version>7.6.1</elasticsearch.version>
</properties>

添加依赖

<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
</dependency>

添加初始化 RestHighLevelClient 的配置类

索引库操作

创建索引库

CreateIndexRequest request = new CreateIndexRequest("users");
CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(request, RequestOptions.DEFAULT);

判断索引库是否存在

GetIndexRequest request = new GetIndexRequest("users");
boolean exists = restHighLevelClient.indices().exists(request, RequestOptions.DEFAULT);

删除索引库

DeleteIndexRequest indexRequest = new DeleteIndexRequest("users");
AcknowledgedResponse delete = restHighLevelClient.indices().delete(indexRequest, RequestOptions.DEFAULT);
delete.isAcknowledged();//返回 true 删除成功,返回 false 删除失败

文档操作

添加文档

//将新闻添加到 mysql 的同时,将数据同步更新到 ES,为搜索提供数据
News news = new News();
news.setId(3);
news.setTitle("美国今年要总统选择,拜登着急了");
news.setImg("aaaaasssss.jpg");
IndexRequest indexRequest = new IndexRequest("news").id(news.getId().toString());
//将对象转为 json 存进 ES
indexRequest.source(new ObjectMapper().writeValueAsString(news),XContentType.JSON);
restHighLevelClient.index(indexRequest,RequestOptions.DEFAULT);

修改文档

News news = new News();
news.setId(3);
news.setTitle("中国航母开往美国,准备开战,拜登着急了");
news.setImg("dddddddddddd.jpg");
UpdateRequest updateRequest = new UpdateRequest("news",news.getId().toString());
updateRequest.doc(new ObjectMapper().writeValueAsString(news), XContentType.JSON);
restHighLevelClient.update(updateRequest,RequestOptions.DEFAULT);

查询文档

GetRequest getRequest = new GetRequest("news","1");
GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
//获取查询的内容,返回 json 格式
String json = getResponse.getSourceAsString();
//使用 jackson 组件将 json 字符串解析为对象
News news = new ObjectMapper().readValue(json, News.class);

删除文档

DeleteRequest deleteRequest = new DeleteRequest("news","1");
DeleteResponse delete = restHighLevelClient.delete(deleteRequest, RequestOptions.DEFAULT);

最后是非常强大的搜索功能-搜索文档

SearchRequest searchRequest = new SearchRequest("news");
SearchRequest searchRequest = new SearchRequest("news");
//精确条件查询
searchRequest.source().query(QueryBuilders.termQuery("title","美国"));
//发送查询请求
SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
//接收查询结果
SearchHits hits = search.getHits();
//组装查询结果
ArrayList<News> list = new ArrayList<>();
//取出结果集
for (SearchHit searchHit : hits.getHits()){
String json = searchHit.getSourceAsString();
News news = new ObjectMapper().readValue(json,News.class);
list.add(news);
}