SpringBoot - 检索Elasticsearch

概述

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

SpringBoot整合Elasticsearch

环境准备

1. Docker下载Elasticsearch镜像并启动容器

   docker search elasticsearch
   elasticsearch启动时默认占用2G的堆内存空间，内存不够会启动失败，所以必须限制它的内存空间
   9200web页面访问端口，9300elasticsearch分布式节点间通信端口
   docker run -e ES_JAVA_OPTS "-Xms256m -Xmx256m" -d -p 9200:9200 -p 9300:9300 --name ES01 elasticsearch
   

2. 浏览器访问IP:9200显示如下页面即启动成功

3. 创建项目，引入依赖如下

   <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
           </dependency>
           <!-- https://mvnrepository.com/artifact/io.searchbox/jest -->
           <dependency>
               <groupId>io.searchbox</groupId>
               <artifactId>jest</artifactId>
               <version>6.3.1</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>
   

4. 配置application.properties

   #使用jest和ES交互时需要配置访问的uri
   spring.elasticsearch.jest.uris=http://IP:9200
   
   #使用SpringData Elasticsearch和ES交互时需要配置
   #集群名字，web界面显示
   spring.data.elasticsearch.cluster-name=docker-cluster
   #集群节点，注意是9300端口
   spring.data.elasticsearch.cluster-nodes=IP:9300
   

说明

SpringBoot默认支持两种技术和Elasticsearch交互

1. Jest（默认不生效）需要导入Jest的工具包：io.searchbox.client.JestClient
2. SpringData Elasticsearch
   1. Client节点信息：clusterNodes和clusterName
   2. ElasticSearchTemplate 操作ES
   3. 编写一个ElasticSearchRepository的子接口来操作ES

测试和Elasticsearch交互

1.使用jestClient

@Autowired
JestClient jestClient;

@Test
    public void testSave() {
        //1.给ES中索引（保存）一个文档
        Article article = new Article();
        article.setId(1);
        article.setAuthor("chenyu");
        article.setTitle("Tell you how to brag");
        article.setContent("puniangyi");
        //构建一个索引功能
        Index index = new Index.Builder(article).index("yubrother").type("666").build();
        try {
            jestClient.execute(index);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

@Test
    public void testSearch(){
    // 查询表达式
    String json =
        "{\n"
            + "    \"query\" : {\n"
            + "        \"match\" : {\n"
            + "            \"content\" : \"puniangyi\"\n"
            + "        }\n"
            + "    }\n"
            + "}";
        //构建搜索功能
        Search search = new Search.Builder(json).addIndex("yubrother").addType("666").build();
        try {
            SearchResult result = jestClient.execute(search);
            System.out.println(result.getJsonString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

2.使用ElasticsearchRepository的子接口

//ElasticsearchRepository支持jpa规范
public interface BookRepository extends ElasticsearchRepository<Book,Integer> {
    public Book findByBookNameLike(String bookName);
}

@Autowired
ElasticsearchTemplate elasticsearchTemplate;

@Test
    public void test01(){
        Book book = new Book();
        book.setId(1);
        book.setBookName("西游记");
        book.setAuthor("吴承恩");
        bookRepository.index(book);
    }

@Test
    public void test02(){
        //Optional可以进行空值检测
        Optional<Book> book = bookRepository.findById(1);
        System.out.println(book);
    }

3.使用ElasticsearchTemplate

@Autowired
ElasticsearchTemplate elasticsearchTemplate;

@Test
    public void test03(){
        Book book = new Book();
        book.setId(2);
        book.setBookName("三国演义");
        book.setAuthor("罗贯中");
        IndexQuery indexQuery = new IndexQueryBuilder().withId((book.getId()).toString()).withObject(book).build();
        elasticsearchTemplate.index(indexQuery);
    }

附 Elasticsearch: 权威指南