本文案例，在英文文章索引下中搜索包含指定单词的文章，对包含指定单词的句子高亮显示。主要介绍在springboot中如何集成elasticsearch，以及常用api。
引入依赖配置连接org.springframework.boot spring-boot-starter-parent 2.3.0.RELEASE org.springframework.boot spring-boot-starter-data-elasticsearch
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.client.ClientConfiguration;
import org.springframework.data.elasticsearch.client.RestClients;
import org.springframework.data.elasticsearch.config.AbstractElasticsearchConfiguration;
@Configuration
public class ElasticSearchClient extends AbstractElasticsearchConfiguration {
@Override
@Bean
public RestHighLevelClient elasticsearchClient() {
ClientConfiguration clientConfiguration = ClientConfiguration.builder()
.connectedTo("127.0.0.1:9200").build();
return RestClients.create(clientConfiguration).rest();
}
}
添加数据（添加索引的文档）
索引相当于是数据库，一个文档相当于是具体一条数据，表对应的概念是类型（type）但是在elasticsearch最新版以及取消type了。
添加index以及document的代码如下：
@Data
@Document(indexName = "article")//指定index，也可以指定type
public class BdArticle implements Serializable {
private static final long serialVersionUID=1L;
//指定在elasticsearch中的id
@TableId(value = "id", type = IdType.AUTO)
@Id
private Long id;
//指定在elasticsearch中字段类型，还可以设置sort
@Field(type = FieldType.Text)
private String title;
@Field(type = FieldType.Text)
private String photo;
@Field(type = FieldType.Text)
private String context;
@Field(type = FieldType.Text)
private Long wordCount;
@Field(type = FieldType.Text)
private Long createTime;
@Field(type = FieldType.Text)
private Long updateTime;
}
把字段排除的注解也有，在实体类影时可以操作的地方很多，大家可以补充。
@Service
public class ArticleServiceImpl implements ArticleService {
@Autowired
private ElasticsearchOperations elasticsearchOperations;
@Override
@Transactional(rollbackFor = Exception.class)
public void addBdArticle(BdArticle bdArticle) {
elasticsearchOperations.save(bdArticle);
}
}
除了映射实体类也可以通过api加入单独的字段。
查询数据@SpringBootTest(classes = ReciteWordsApplication.class)
@RunWith(SpringJUnit4ClassRunner.class)
public class ArticleELKTest {
@Autowired
private BdArticleService bdArticleService;
@Autowired
private ElasticsearchOperations elasticsearchOperations;
@Autowired
private RestHighLevelClient restHighLevelClient;
@Test
public void searchWordInArticles() throws IOException {
String wordText = "is";
// 拿到要查询的索引
SearchRequest searchRequest = new SearchRequest("article");
// 构建查询条件
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
//指定返回字段
String[] fields = {"id","title","context"};
sourceBuilder.fetchSource(fields, Strings.EMPTY_ARRAY);
//match查询，可选 sourceBuilder.query(QueryBuilders.matchQuery("context",wordText));
//高亮设置
HighlightBuilder highlightBuilder = new HighlightBuilder();
//设置高亮渲染
String preTag = "";
String postTag = "";
HighlightBuilder.Field highlightContext = new HighlightBuilder.Field("context")
.numOfFragments(1)//没一个document中返回的条数（因为一个document中就可以有好多个关键词）
.preTags(preTag)
.postTags(postTag);
highlightBuilder.field(highlightContext);
//设置返回document条数
sourceBuilder.size(3);
sourceBuilder.highlighter(highlightBuilder);
searchRequest.source(sourceBuilder);
// 进行查询
SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
//对返回值进行处理
org.elasticsearch.search.SearchHit[] hits = searchResponse.getHits().getHits();
if(hits==null||hits.length==0){
return null;
}
List list = new ArrayList<>();
for (SearchHit hit : hits) {
Map highlightFields = hit.getHighlightFields();
Map sourceAsMap = hit.getSourceAsMap();
BdArticle bdArticle = new BdArticle();
bdArticle.setId(Long.parseLong(String.valueOf(sourceAsMap.get("id"))));
bdArticle.setTitle(String.valueOf(sourceAsMap.get("title")));
bdArticle.setContext(highlightFields.get("context").getFragments()[0].string());
list.add(bdArticle);
}
System.out.println(list);
}
}
对应的DSL查询语句以及查询结果：
{
"query":{
"match":{
"context":"is"
}
},
"_source":["id"],
"highlight":{
"fields":{
"context":{
"number_of_fragments":1
}
}
}
}
res：重点看hits
{
"took": 20,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 6,
"relation": "eq"
},
"max_score": 0.14691809,
"hits": [
{
"_index": "article",
"_type": "_doc",
"_id": "8",
"_score": 0.14691809,
"_source": {
"id": 8
},
"highlight": {
"context": [
"Classified advertising is that advertising which is grouped in certain sections of the paper and is thus"
]
}
},
{
"_index": "article",
"_type": "_doc",
"_id": "3",
"_score": 0.14463511,
"_source": {
"id": 3
},
"highlight": {
"context": [
"There is considerable sentiment about the “corruption” of women’s language—which of course is viewed"
]
}
},
{
"_index": "article",
"_type": "_doc",
"_id": "2",
"_score": 0.1358716,
"_source": {
"id": 2
},
"highlight": {
"context": [
"Obviously it is not of ours.”"
]
}
},
{
"_index": "article",
"_type": "_doc",
"_id": "1",
"_score": 0.12783799,
"_source": {
"id": 1
},
"highlight": {
"context": [
"Today it is a giant advertising company, worth $100 billion."
]
}
},
{
"_index": "article",
"_type": "_doc",
"_id": "4",
"_score": 0.11044833,
"_source": {
"id": 4
},
"highlight": {
"context": [
"\n The challenge is particularly evident in the work-place."
]
}
},
{
"_index": "article",
"_type": "_doc",
"_id": "5",
"_score": 0.10031616,
"_source": {
"id": 5
},
"highlight": {
"context": [
"Like most people, I’ve long understood that I will be judged by my occupation, that my profession is"
]
}
}
]
}
}
参考
五.全文检索ElasticSearch经典入门-ElasticSearch Java实战
可以看一下视频或者找api文档，springboot对elasticsearch整合的类和注解还是比较多的，包括实体类映射等，elasticsearch的概念也非常多，到了集群操作更加复制。
