SpringBoot elasticsearch

SpringBoot 整合 elasticsearch

Posted on 2020-11-09,10 min read

一、简介

我们的应用经常需要添加检索功能,开源的 ElasticSearch 是目前全文搜索引擎的 首选。他可以快速的存储、搜索和分析海量数据。Spring Boot通过整合Spring Data ElasticSearch为我们提供了非常便捷的检索功能支持;
Elasticsearch是一个分布式搜索服务,提供Restful API,底层基于Lucene,采用 多shard(分片)的方式保证数据安全,并且提供自动resharding的功能,github 等大型的站点也是采用了ElasticSearch作为其搜索服务,

二、安装elasticsearch

我们采用 docker镜像安装的方式。

#下载镜像
docker pull elasticsearch
#启动镜像,elasticsearch 启动是会默认分配2G的内存 ,我们启动是设置小一点,防止我们内存不够启动失败
#9200是elasticsearch 默认的web通信接口,9300是分布式情况下,elasticsearch个节点通信的端口
docker run -e ES_JAVA_OPTS="-Xms256m -Xmx256m" -d -p 9200:9200 -p 9300:9300 --name es01 5c1e1ecfe33a

访问 127.0.0.1:9200 如下图,说明安装成功

img

三、elasticsearch的一些概念

  • 员工文档 的形式存储为例:一个文档代表一个员工数据。存储数据到 ElasticSearch 的行为叫做索引 ,但在索引一个文档之前,需要确定将文档存 储在哪里。
  • 一个 ElasticSearch 集群可以 包含多个索引 ,相应的每个索引可以包含多个类型。这些不同的类型存储着多个文档 ,每个文档又有 多个 属性
  • 类似关系:
  • 索引-数据库
  • 类型-表
  • 文档-表中的记录 – 属性-列
img

elasticsearch使用可以参早官方文档,在这里不在讲解。

四、整合 elasticsearch

创建项目 springboot-elasticsearch,引入web支持 SpringBoot 提供了两种方式操作elasticsearch,Jest 和 SpringData。

Jest 操作 elasticsearch

Jest是ElasticSearch的Java HTTP Rest客户端。

ElasticSearch已经有一个Java API,ElasticSearch也在内部使用它,但是Jest填补了空白,它是ElasticSearch Http Rest接口缺少的客户端。

1. pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.gf</groupId>
	<artifactId>springboot-elasticsearch</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>springboot-elasticsearch</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.1.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-elasticsearch</artifactId>
	</dependency>
		<dependency>
			<groupId>io.searchbox</groupId>
			<artifactId>jest</artifactId>
			<version>5.3.3</version>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>


</project>

####2. application.properties

spring.elasticsearch.jest.uris=http://127.0.0.1:9200

3. Article

package com.gf.entity;


import io.searchbox.annotations.JestId;

public class Article {

    @JestId
    private Integer id;
    private String author;
    private String title;
    private String content;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder( "{\"Article\":{" );
        sb.append( "\"id\":" )
                .append( id );
        sb.append( ",\"author\":\"" )
                .append( author ).append( '\"' );
        sb.append( ",\"title\":\"" )
                .append( title ).append( '\"' );
        sb.append( ",\"content\":\"" )
                .append( content ).append( '\"' );
        sb.append( "}}" );
        return sb.toString();
    }


}

4. springboot测试类

package com.gf;

import com.gf.entity.Article;
import io.searchbox.client.JestClient;
import io.searchbox.core.Index;
import io.searchbox.core.Search;
import io.searchbox.core.SearchResult;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.IOException;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootElasticsearchApplicationTests {

	@Autowired
	JestClient jestClient;

	@Test
	public void createIndex() {
		//1. 给ES中索引(保存)一个文档
		Article article = new Article();
		article.setId( 1 );
		article.setTitle( "好消息" );
		article.setAuthor( "张三" );
		article.setContent( "Hello World" );

		//2. 构建一个索引
		Index index = new Index.Builder( article ).index( "gf" ).type( "news" ).build();
		try {
			//3. 执行
			jestClient.execute( index );
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	@Test
	public void search() {
		//查询表达式
		String query = "{\n" +
				"    \"query\" : {\n" +
				"        \"match\" : {\n" +
				"            \"content\" : \"hello\"\n" +
				"        }\n" +
				"    }\n" +
				"}";

		//构建搜索功能
		Search search = new Search.Builder( query ).addIndex( "gf" ).addType( "news" ).build();

		try {
			//执行
			SearchResult result = jestClient.execute( search );
			System.out.println(result.getJsonString());
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

}

Jest的更多api ,可以参照github的文档:https://github.com/searchbox-io/Jest

SpringData 操作 elasticsearch

1. application.properties

spring.data.elasticsearch.cluster-name=elasticsearch
spring.data.elasticsearch.cluster-nodes=127.0.0.1:9300

2. Book

package com.gf.entity;

@Document( indexName = "gf" , type = "book")
public class Book {
    private Integer id;
    private String bookName;
    private String author;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder( "{\"Book\":{" );
        sb.append( "\"id\":" )
                .append( id );
        sb.append( ",\"bookName\":\"" )
                .append( bookName ).append( '\"' );
        sb.append( ",\"author\":\"" )
                .append( author ).append( '\"' );
        sb.append( "}}" );
        return sb.toString();
    }
    
}

3. BookRepository

package com.gf.repository;


import com.gf.entity.Book;
import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

import java.util.List;

public interface BookRepository extends ElasticsearchRepository<Book, Integer>{

    List<Book> findByBookNameLike(String bookName);

}

4. springboot 测试类

package com.gf;

import com.gf.entity.Article;
import com.gf.entity.Book;
import com.gf.repository.BookRepository;
import io.searchbox.client.JestClient;
import io.searchbox.core.Index;
import io.searchbox.core.Search;
import io.searchbox.core.SearchResult;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.IOException;
import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootElasticsearchApplicationTests {

	@Autowired
	BookRepository bookRepository;
	
	@Test
	public void createIndex2(){
		Book book = new Book();
		book.setId(1);
		book.setBookName("西游记");
		book.setAuthor( "吴承恩" );
		bookRepository.index( book );
	}

	@Test
	public void useFind() {
		List<Book> list = bookRepository.findByBookNameLike( "游" );
		for (Book book : list) {
			System.out.println(book);
		}

	}

}

我们启动测试 ,发现报错 。 img 这个报错的原因是springData的版本与我elasticsearch的版本有冲突,下午是springData官方文档给出的适配表。 img 我们使用的springdata elasticsearch的 版本是3.1.3 ,对应的版本应该是6.2.2版本,而我们是的 elasticsearch 是 5.6.9,所以目前我们需要更换elasticsearch的版本为6.X

docker pull elasticsearch:6.5.1
docker run -e ES_JAVA_OPTS="-Xms256m -Xmx256m" -d -p 9200:9200 -p 9300:9300 --name es02 镜像ID

访问127.0.0.1:9200 img

集群名为docker-cluster,所以我们要修改application.properties的配置了

spring.data.elasticsearch.cluster-name=docker-cluster
spring.data.elasticsearch.cluster-nodes=127.0.0.1:9300

我们再次进行测试,测试可以通过了 。我们访问http://127.0.0.1:9200/gf/book/1,可以得到我们存入的索引信息。 img

源码下载:https://github.com/gf-huanchupk/SpringBootLearning

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