9200: HTTP
9300: TCP
spring-data-elasticsearch:transport-api.jar;
springboot版本不同，ransport-api.jar不同，不能适配es版本
7.x已经不建议使用，8以后就要废弃
jestClient: 非官方，更新慢；
RestTemplate：模拟HTTP请求，ES很多操作需要自己封装，麻烦；
HttpClient：同上；
Elasticsearch-Rest-Client：官方RestClient，封装了ES操作，API层次分明，上手简单；
最终选择Elasticsearch-Rest-Client（elasticsearch-rest-high-level-client）；
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high.html
导入依赖
这里的版本要和所安装的ELK版本匹配。
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.4.2</version>
</dependency>
在spring-boot-dependencies中所依赖的ELK版本位6.8.7，需要在项目中将它改为7.4.2
<properties>
<elasticsearch.version>7.4.2</elasticsearch.version>
</properties>
编写测试类
@Test
public void indexData() throws IOException {
IndexRequest indexRequest = new IndexRequest ("users");
User user = new User();
user.setUserName("张三");
user.setAge(20);
user.setGender("男");
String jsonString = JSON.toJSONString(user);
//设置要保存的内容
indexRequest.source(jsonString, XContentType.JSON);
//执行创建索引和保存数据
IndexResponse index = client.index(indexRequest, GulimallElasticSearchConfig.COMMON_OPTIONS);
System.out.println(index);
}
测试获取数据
https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-search.html
@Test
public void searchData() throws IOException {
GetRequest getRequest = new GetRequest(
"users",
"_-2vAHIB0nzmLJLkxKWk");
GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);
System.out.println(getResponse);
String index = getResponse.getIndex();
System.out.println(index);
String id = getResponse.getId();
System.out.println(id);
if (getResponse.isExists()) {
long version = getResponse.getVersion();
System.out.println(version);
String sourceAsString = getResponse.getSourceAsString();
System.out.println(sourceAsString);
Map<String, Object> sourceAsMap = getResponse.getSourceAsMap();
System.out.println(sourceAsMap);
byte[] sourceAsBytes = getResponse.getSourceAsBytes();
} else {
}
}
搜索address中包含mill的所有人的年龄分布以及平均年龄，平均薪资
GET bank/_search
{
"query": {
"match": {
"address": "Mill"
}
},
"aggs": {
"ageAgg": {
"terms": {
"field": "age",
"size": 10
}
},
"ageAvg": {
"avg": {
"field": "age"
}
},
"balanceAvg": {
"avg": {
"field": "balance"
}
}
}
}
java实现
/**
* 复杂检索:在bank中搜索address中包含mill的所有人的年龄分布以及平均年龄，平均薪资
* @throws IOException
*/
@Test
public void searchData() throws IOException {
//1. 创建检索请求
SearchRequest searchRequest = new SearchRequest();
//1.1）指定索引
searchRequest.indices("bank");
//1.2）构造检索条件
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder.query(QueryBuilders.matchQuery("address","Mill"));
//1.2.1)按照年龄分布进行聚合
TermsAggregationBuilder ageAgg=AggregationBuilders.terms("ageAgg").field("age").size(10);
sourceBuilder.aggregation(ageAgg);
//1.2.2)计算平均年龄
AvgAggregationBuilder ageAvg = AggregationBuilders.avg("ageAvg").field("age");
sourceBuilder.aggregation(ageAvg);
//1.2.3)计算平均薪资
AvgAggregationBuilder balanceAvg = AggregationBuilders.avg("balanceAvg").field("balance");
sourceBuilder.aggregation(balanceAvg);
System.out.println("检索条件："+sourceBuilder);
searchRequest.source(sourceBuilder);
//2. 执行检索
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
System.out.println("检索结果："+searchResponse);
//3. 将检索结果封装为Bean
SearchHits hits = searchResponse.getHits();
SearchHit[] searchHits = hits.getHits();
for (SearchHit searchHit : searchHits) {
String sourceAsString = searchHit.getSourceAsString();
Account account = JSON.parseObject(sourceAsString, Account.class);
System.out.println(account);
}
//4. 获取聚合信息
Aggregations aggregations = searchResponse.getAggregations();
Terms ageAgg1 = aggregations.get("ageAgg");
for (Terms.Bucket bucket : ageAgg1.getBuckets()) {
String keyAsString = bucket.getKeyAsString();
System.out.println("年龄："+keyAsString+" ==> "+bucket.getDocCount());
}
Avg ageAvg1 = aggregations.get("ageAvg");
System.out.println("平均年龄："+ageAvg1.getValue());
Avg balanceAvg1 = aggregations.get("balanceAvg");
System.out.println("平均薪资："+balanceAvg1.getValue());
}
