Elasticsearch集成Sprinng Data

1. 概述

Spring Data是一个用于简化数据库、非关系型数据库、索引库访问，并支持云服务的开源框架。其主要目标是使得对数据的访问变得方便快捷，并支持 map-reduce框架和云计算数据服务。Spring Data可以极大的简化JPA(Elasticsearch…)的写法，可以在几乎不用写实现的情况下，实现对数据的访问和操作。除了CRUD 外，还包括如分页、排序等一些常用的功能。

Spring Data Elasticsearch基于Spring Data API简化 Elasticsearch 操作，将原始操作Elasticsearch 的客户端API进行封装。Spring Data为Elasticsearch 项目提供集成搜索引擎。Spring Data Elasticsearch POJO的关键功能区域为中心的模型与Elastichsearch交互文档和轻松地编写一个存储索引库数据访问层。

2. 代码示例

• pom文件

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.6.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>com.lun</groupId>
    <artifactId>SpringDataWithES</artifactId>
    <version>1.0.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
        </dependency>
    </dependencies>
</project>

• 在 resources 目录中增加application.properties文件

# es 服务地址
elasticsearch.host=127.0.0.1
# es 服务端口
elasticsearch.port=9200
# 配置日志级别,开启 debug 日志
logging.level.com.atguigu.es=debug

• 数据实体类

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
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;

@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
@Document(indexName = "shopping", shards = 3, replicas = 1)
public class Product {
    //必须有 id,这里的 id 是全局唯一的标识，等同于 es 中的"_id"
    @Id
    private Long id;//商品唯一标识

    /**
     * type : 字段数据类型
     * analyzer : 分词器类型
     * index : 是否索引(默认:true)
     * Keyword : 短语,不进行分词
     */
    @Field(type = FieldType.Text, analyzer = "ik_max_word")
    private String title;//商品名称

    @Field(type = FieldType.Keyword)
    private String category;//分类名称

    @Field(type = FieldType.Double)
    private Double price;//商品价格

    @Field(type = FieldType.Keyword, index = false)
    private String images;//图片地址
}

• 配置类

ElasticsearchRestTemplate是spring-data-elasticsearch项目中的一个类,和其他spring项目中的 template类似。
在新版的spring-data-elasticsearch 中，ElasticsearchRestTemplate 代替了原来的ElasticsearchTemplate。
原因是ElasticsearchTemplate基于TransportClient，TransportClient即将在8.x 以后的版本中移除。所以，我们推荐使用ElasticsearchRestTemplate。
ElasticsearchRestTemplate基于RestHighLevelClient客户端的。需要自定义配置类，继承AbstractElasticsearchConfiguration，并实现elasticsearchClient()抽象方法，创建RestHighLevelClient对象。

AbstractElasticsearchConfiguration源码：

package org.springframework.data.elasticsearch.config;

import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.data.elasticsearch.core.ElasticsearchRestTemplate;
import org.springframework.data.elasticsearch.core.convert.ElasticsearchConverter;

/**
 * @author Christoph Strobl
 * @author Peter-Josef Meisch
 * @since 3.2
 * @see ElasticsearchConfigurationSupport
 */
public abstract class AbstractElasticsearchConfiguration extends ElasticsearchConfigurationSupport {

    //需重写本方法
    public abstract RestHighLevelClient elasticsearchClient();

    @Bean(name = { "elasticsearchOperations", "elasticsearchTemplate" })
    public ElasticsearchOperations elasticsearchOperations(ElasticsearchConverter elasticsearchConverter) {
        return new ElasticsearchRestTemplate(elasticsearchClient(), elasticsearchConverter);
    }
}

需要自定义配置类，继承AbstractElasticsearchConfiguration，并实现elasticsearchClient()抽象方法，创建RestHighLevelClient对象。

import lombok.Data;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.config.AbstractElasticsearchConfiguration;

@ConfigurationProperties(prefix = "elasticsearch")
@Configuration
@Data
public class ElasticsearchConfig extends AbstractElasticsearchConfiguration{

    private String host ;
    private Integer port ;
    //重写父类方法
    @Override
    public RestHighLevelClient elasticsearchClient() {
        RestClientBuilder builder = RestClient.builder(new HttpHost(host, port));
        RestHighLevelClient restHighLevelClient = new
                RestHighLevelClient(builder);
        return restHighLevelClient;
    }
}

• DAO 数据访问对象

import com.lun.model.Product;
import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface ProductDao extends ElasticsearchRepository<Product, Long>{

}

• 索引操作

import com.lun.model.Product;
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.data.elasticsearch.core.ElasticsearchRestTemplate;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringDataESIndexTest {
    //注入 ElasticsearchRestTemplate
    @Autowired
    private ElasticsearchRestTemplate elasticsearchRestTemplate;
    //创建索引并增加映射配置
    @Test
    public void createIndex(){
        //创建索引，系统初始化会自动创建索引
        System.out.println("创建索引");
    }

    @Test
    public void deleteIndex(){
        //创建索引，系统初始化会自动创建索引
        boolean flg = elasticsearchRestTemplate.deleteIndex(Product.class);
        System.out.println("删除索引 = " + flg);
    }
}

• 文档操作

import com.lun.dao.ProductDao;
import com.lun.model.Product;
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.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.ArrayList;
import java.util.List;

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

    @Autowired
    private ProductDao productDao;
    /**
     * 新增
     */
    @Test
    public void save(){
        Product product = new Product();
        product.setId(2L);
        product.setTitle("华为手机");
        product.setCategory("手机");
        product.setPrice(2999.0);
        product.setImages("http://www.atguigu/hw.jpg");
        productDao.save(product);
    }
    //POSTMAN, GET http://localhost:9200/product/_doc/2

    //修改
    @Test
    public void update(){
        Product product = new Product();
        product.setId(2L);
        product.setTitle("小米 2 手机");
        product.setCategory("手机");
        product.setPrice(9999.0);
        product.setImages("http://www.atguigu/xm.jpg");
        productDao.save(product);
    }
    //POSTMAN, GET http://localhost:9200/product/_doc/2


    //根据 id 查询
    @Test
    public void findById(){
        Product product = productDao.findById(2L).get();
        System.out.println(product);
    }

    @Test
    public void findAll(){
        Iterable<Product> products = productDao.findAll();
        for (Product product : products) {
            System.out.println(product);
        }
    }

    //删除
    @Test
    public void delete(){
        Product product = new Product();
        product.setId(2L);
        productDao.delete(product);
    }
    //POSTMAN, GET http://localhost:9200/product/_doc/2

    //批量新增
    @Test
    public void saveAll(){
        List<Product> productList = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            Product product = new Product();
            product.setId(Long.valueOf(i));
            product.setTitle("["+i+"]小米手机");
            product.setCategory("手机");
            product.setPrice(1999.0 + i);
            product.setImages("http://www.atguigu/xm.jpg");
            productList.add(product);
        }
        productDao.saveAll(productList);
    }

    //分页查询
    @Test
    public void findByPageable(){
        //设置排序(排序方式，正序还是倒序，排序的 id)
        Sort sort = Sort.by(Sort.Direction.DESC,"id");
        int currentPage=0;//当前页，第一页从 0 开始， 1 表示第二页
        int pageSize = 5;//每页显示多少条
        //设置查询分页
        PageRequest pageRequest = PageRequest.of(currentPage, pageSize,sort);
        //分页查询
        Page<Product> productPage = productDao.findAll(pageRequest);
        for (Product Product : productPage.getContent()) {
            System.out.println(Product);
        }
    }
}

• 文档搜索

import com.lun.dao.ProductDao;
import com.lun.model.Product;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.TermQueryBuilder;
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.data.domain.PageRequest;
import org.springframework.test.context.junit4.SpringRunner;

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

    @Autowired
    private ProductDao productDao;
    /**
     * term 查询
     * search(termQueryBuilder) 调用搜索方法，参数查询构建器对象
     */
    @Test
    public void termQuery(){
        TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("title", "小米");
                Iterable<Product> products = productDao.search(termQueryBuilder);
        for (Product product : products) {
            System.out.println(product);
        }
    }
    /**
     * term 查询加分页
     */
    @Test
    public void termQueryByPage(){
        int currentPage= 0 ;
        int pageSize = 5;
        //设置查询分页
        PageRequest pageRequest = PageRequest.of(currentPage, pageSize);
        TermQueryBuilder termQueryBuilder = QueryBuilders.termQuery("title", "小米");
                Iterable<Product> products =
                        productDao.search(termQueryBuilder,pageRequest);
        for (Product product : products) {
            System.out.println(product);
        }
    }

}