一、前言
今天来讲解一下，如何使用java程序操作elasticsearch，实现数据的增删改查，在以往，我们都是通过开启kibana服务来实现es数据的增删改查，但是在真实的开发场景中，这些操作都是需要移植到程序中的，于是就有了今天这篇文章，学习如何使用java程序实现elasticsearch数据的增删改查。
二、使用步骤
1.导入依赖，配置环境
以SpringBoot为基础，创建一个SpringBoot项目。
<!--java版es客户端-->
<dependency>
<groupId>org.elasticsearch.client</groupId>
<artifactId>elasticsearch-rest-high-level-client</artifactId>
<version>7.6.2</version>
</dependency>
<!--特别需要注意的是，填写自己需要使用的es版本，如果没有自己指定，那么就会使用默认的低版本（会报错，这是一个坑）-->
<properties>
<java.version>1.8</java.version>
<elasticsearch-version>7.6.2</elasticsearch-version>
</properties>
//我们编写一个测试类，和一个实体类，用于测试elasticsearch中的索引和数据的增删改查的基本操作。
//实体类（使用lombok插件自动生成get/set,有参无参构造，以及toString()方法.）
package com.lhh.es.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@NoArgsConstructor
@AllArgsConstructor
@Data
public class User {
private int age;
private String name;
private char sex;
}
//注入一个elasticsearch的客户端，并把它加入到spring容器当中
@Bean
private static synchronized RestHighLevelClient makeConnection() {
if (restHighLevelClient == null) {
restHighLevelClient = new RestHighLevelClient(
RestClient.builder(
new HttpHost("localhost", 9200, "http")
));
}
return restHighLevelClient;
}
2.索引测试
创建索引
/*
* 创建一个索引
* */
@Test
void testCreateIndex() throws IOException {
/*创建了一个索引*/
CreateIndexRequest createIndexRequest = new CreateIndexRequest("my_java_index1");
/*运行一个创建索引的命令*/
CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);
/*打印创建索引之后的信息。*/
System.out.println(createIndexResponse.index());
}
判断索引是否存在
/*判断索引是否存在*/
@Test
void testGetIndex() throws IOException {
/*定义一个获取索引的操作*/
GetIndexRequest getIndexRequest = new GetIndexRequest("my_java_index1");
/*运行获取索引的命令*/
boolean bool = restHighLevelClient.indices().exists(getIndexRequest, RequestOptions.DEFAULT);
/*打印信息*/
System.out.println(bool);
}
删除索引
/*删除索引*/
@Test
void testDeleteIndex() throws IOException {
/*定义一个删除的操作*/
DeleteIndexRequest my_java_index = new DeleteIndexRequest("my_java_index1");
/*运行删除命令*/
AcknowledgedResponse delete = restHighLevelClient.indices().delete(my_java_index, RequestOptions.DEFAULT);
/*验证是否删除*/
System.out.println(delete.isAcknowledged());
}
3.文档测试
创建文档（id需要自己手动设置）
/*
* 创建文档
* */
@Test
void testCreateDocument() throws IOException {
IndexRequest my_java_index1 = new IndexRequest("my_java_index1");
/*设置文档id*/
my_java_index1.id("1");
my_java_index1.timeout("2s");
User user = new User(12, "miracle", '男');
my_java_index1.source(JSON.toJSONString(user), XContentType.JSON);
IndexResponse index = restHighLevelClient.index(my_java_index1, RequestOptions.DEFAULT);
/*查看状态*/
System.out.println(index.status());
/*或许文档的信息*/
System.out.println(index.toString());
}
判断文档是否存在（注意和索引的区别）
/*
* 判断文档是否存在
* */
@Test
void getDocument() throws IOException {
GetRequest getRequest = new GetRequest("my_java_index1", "1");
boolean exists = restHighLevelClient.exists(getRequest, RequestOptions.DEFAULT);
System.out.println(exists);
}
获取文档的具体信息
/*
* 获取文档的具体信息
* */
@Test
void getDocumentMessage() throws IOException {
GetRequest getRequest = new GetRequest("my_java_index1", "1");
GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
/*获取字段信息*/
System.out.println(getResponse.getType());
System.out.println();
System.out.println(getResponse.getSource());
}
删除文档
/*
* 删除文档
* */
@Test
void deleteDocument() throws IOException {
DeleteRequest deleteRequest = new DeleteRequest("my_java_index1", "1");
DeleteResponse deleteResponse = restHighLevelClient.delete(deleteRequest, RequestOptions.DEFAULT);
/*获取删除文档的信息*/
System.out.println(deleteResponse.remoteAddress());
System.out.println(deleteResponse.status());
}
更新文档
/*更新文档*/
@Test
void testUpdateDocument() throws IOException {
UpdateRequest updateRequest = new UpdateRequest("my_java_index1", "2");
updateRequest.doc(JSON.toJSONString(new User(120,"zhangsan",'女')),XContentType.JSON);
UpdateResponse updateResponse = restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);
/*获取更新之后的信息*/
System.out.println(updateResponse.status());
}
批量插入数据
/*
* 批量插入
*
* */
@Test
void testBulkInsert() throws IOException {
IndexRequest indexRequest = new IndexRequest("my_java_index1");
List<User> lists = new ArrayList<>(10);
User user = new User(25, "lisi", '男');
User user1 = new User(27, "zhaoliu", '女');
User user2 = new User(20, "tianqi", '男');
User user3 = new User(15, "haihui", '男');
lists.add(user1);
lists.add(user2);
lists.add(user3);
lists.add(user);
BulkRequest bulkRequest = new BulkRequest();
for (int i = 0; i < lists.size(); i++) {
bulkRequest.add(indexRequest.id("" + (i + 1)).source(JSON.toJSONString(lists.get(i)), XContentType.JSON));
}
BulkResponse bulk = restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);
System.out.println(bulk.hasFailures());
}
批量查询(重要)
/*
* 批量查询，目前还有点问题尚待解决，会报错。
* */
@Test
void testSearch() throws IOException {
SearchRequest searchRequest = new SearchRequest("my_java_index1");
/*构建搜索的条件*/
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("name", "zhangsan");
searchSourceBuilder.query(termQueryBuilder);
searchRequest.source(searchSourceBuilder);
SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
System.out.println(JSON.toJSONString(searchResponse.getHits()));
for (SearchHit documentFields : searchResponse.getHits().getHits()) {
System.out.println(documentFields.getSourceAsMap());
}
}
总结
以上介绍了如何增删改查索引 文档还讲解了如何实现批量插入，以及一些复杂的查询。