1.环境准备
本文是作者es系列的第三篇文章,关于es的核心概念移步:
关于es的下载安装教程以及基本使用,移步:
在前文中,我们已经搭建好了一个es+kibana的基础环境,本文将继续使用该环境,演示java操作es。
2.es java api
elasticsearch rest high level client 是 elasticsearch 官方提供的一个 java 客户端库,用于与 elasticsearch 进行交互。这个客户端库是基于 rest 风格的 http 协议,与 elasticsearch 进行通信,提供了更高级别的抽象,使得开发者可以更方便地使用 java 代码与 elasticsearch 进行交互。
依赖:
<dependency> <groupid>org.elasticsearch</groupid> <artifactid>elasticsearch</artifactid> <version>7.17.3</version> </dependency> <dependency> <groupid>org.elasticsearch.client</groupid> <artifactid>elasticsearch-rest-high-level-client</artifactid> <version>7.17.3</version> </dependency> <dependency> <groupid>org.apache.logging.log4j</groupid> <artifactid>log4j-core</artifactid> <version>2.10.0</version> </dependency> <dependency> <groupid>junit</groupid> <artifactid>junit</artifactid> <version>4.12</version> </dependency> <dependency> <groupid>com.alibaba.fastjson2</groupid> <artifactid>fastjson2</artifactid> <version>2.0.45</version> </dependency>
其实rest high level client的使用逻辑一共就分散步:
- 拼json
- 创建request
- client执行request
创建client:
resthighlevelclient resthighlevelclient = new resthighlevelclient(restclient.builder(new httphost("127.0.0.1",9200,"http")));
创建索引:
@test public void createindex() throws ioexception { //1.拼json //settings settings.builder settings = settings.builder() .put("number_of_shards", 3) .put("number_of_replicas", 1); //mappings xcontentbuilder mappings = jsonxcontent.contentbuilder(). startobject(). startobject("properties"). startobject("name"). field("type", "text"). endobject(). startobject("age"). field("type", "integer"). endobject(). endobject(). endobject(); //2.创建request createindexrequest createindexrequest = new createindexrequest("person").settings(settings).mapping(mappings); //3.client执行request resthighlevelclient.indices().create(createindexrequest, requestoptions.default); }
创建文档:
@test public void createdoc() throws ioexception { person person=new person("1","zou",20); jsonobject json = jsonobject.from(person); system.out.println(json); indexrequest request=new indexrequest("person",null,person.getid().tostring()); request.source(json, xcontenttype.json); indexresponse response = resthighlevelclient.index(request, requestoptions.default); system.out.println(response); }
响应结果:
修改文档:
@test public void updatedoc() throws ioexception { hashmap<string, object> doc = new hashmap(); doc.put("name","张三"); string docid="1"; updaterequest request=new updaterequest("person",null,docid); updateresponse response = resthighlevelclient.update(request, requestoptions.default); system.out.println(response.getresult().tostring()); }
删除文档:
@test public void deletedoc() throws ioexception { deleterequest request=new deleterequest("person",null,"1"); deleteresponse response = resthighlevelclient.delete(request, requestoptions.default); system.out.println(response.getresult().tostring()); }
响应结果:
搜索示例:
import org.elasticsearch.action.search.searchrequest; import org.elasticsearch.action.search.searchresponse; import org.elasticsearch.client.requestoptions; import org.elasticsearch.client.resthighlevelclient; import org.elasticsearch.common.unit.timevalue; import org.elasticsearch.index.query.querybuilders; import org.elasticsearch.search.builder.searchsourcebuilder; import java.io.ioexception; public class elasticsearchsearchexample { public static void main(string[] args) { // 创建 resthighlevelclient 实例,连接到 elasticsearch 集群 resthighlevelclient client = new resthighlevelclient( restclient.builder(new httphost("localhost", 9200, "http")) ); // 构建搜索请求 searchrequest searchrequest = new searchrequest("your_index"); // 替换为实际的索引名称 // 构建查询条件 searchsourcebuilder searchsourcebuilder = new searchsourcebuilder(); searchsourcebuilder.query(querybuilders.matchallquery()); // 查询所有文档 // 设置一些可选参数 searchsourcebuilder.from(0); // 设置起始索引,默认为0 searchsourcebuilder.size(10); // 设置返回结果的数量,默认为10 searchsourcebuilder.timeout(new timevalue(5000)); // 设置超时时间,默认为1分钟 // 将查询条件设置到搜索请求中 searchrequest.source(searchsourcebuilder); try { // 执行搜索请求 searchresponse searchresponse = client.search(searchrequest, requestoptions.default); // 处理搜索响应 system.out.println("search took: " + searchresponse.gettook()); // 获取搜索结果 searchhits hits = searchresponse.gethits(); system.out.println("total hits: " + hits.gettotalhits().value); // 遍历搜索结果 for (searchhit hit : hits.gethits()) { system.out.println("document id: " + hit.getid()); system.out.println("source: " + hit.getsourceasstring()); } } catch (ioexception e) { // 处理异常 e.printstacktrace(); } finally { try { // 关闭客户端连接 client.close(); } catch (ioexception e) { // 处理关闭连接异常 e.printstacktrace(); } } } }
请注意,上述示例中的 your_index
应该替换为你实际的 elasticsearch 索引名称。这个示例使用了简单的 matchallquery
,你可以根据实际需求构建更复杂的查询条件。在搜索响应中,你可以获取到搜索的结果以及相关的元数据。
3.spring boot操作es
在 spring boot 中操作 elasticsearch 通常使用 spring data elasticsearch,以标准的jpa的模式来操作es。
依赖:
<parent> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-parent</artifactid> <version>2.6.x</version> <!-- 选择一个与elasticsearch 7.17.3兼容的spring boot版本 --> </parent> <dependencies> <!-- spring boot starter web --> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-web</artifactid> </dependency> <!-- spring data elasticsearch --> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-data-elasticsearch</artifactid> </dependency> <!-- spring boot starter test (for testing) --> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-test</artifactid> <scope>test</scope> </dependency> </dependencies> application.properties配置:
spring.data.elasticsearch.cluster-nodes=localhost:9200
实体类:
import org.springframework.data.annotation.id; import org.springframework.data.elasticsearch.annotations.document; import org.springframework.data.elasticsearch.annotations.field; import org.springframework.data.elasticsearch.annotations.fieldtype; import java.util.date; @document(indexname = "blogpost_index") public class blogpost { @id private string id; @field(type = fieldtype.text) private string title; @field(type = fieldtype.text) private string content; @field(type = fieldtype.keyword) private string author; @field(type = fieldtype.date) private date publishdate; // 构造函数、getter和setter public blogpost() { } public blogpost(string id, string title, string content, string author, date publishdate) { this.id = id; this.title = title; this.content = content; this.author = author; this.publishdate = publishdate; } // 省略 getter 和 setter 方法 }
dao层:
import org.springframework.data.elasticsearch.repository.elasticsearchrepository; public interface blogpostrepository extends elasticsearchrepository<blogpost, string> { // 你可以在这里定义自定义查询方法 }
service层:
import org.springframework.beans.factory.annotation.autowired; import org.springframework.stereotype.service; import java.util.list; import java.util.optional; @service public class blogpostservice { private final blogpostrepository blogpostrepository; @autowired public blogpostservice(blogpostrepository blogpostrepository) { this.blogpostrepository = blogpostrepository; } public blogpost save(blogpost blogpost) { return blogpostrepository.save(blogpost); } public optional<blogpost> findbyid(string id) { return blogpostrepository.findbyid(id); } public list<blogpost> findall() { return (list<blogpost>) blogpostrepository.findall(); } public void deletebyid(string id) { blogpostrepository.deletebyid(id); } }
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