ElasticSearch——Spring Boot 集成

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1、SpringBoot 集成 ES

1、新建一个Spring Boot 项目，添加 ElasticSearch 模块：

2、修改ES版本

可以看到，SpringBoot帮我们导入的ES版本是7.12.1：

而我们本地使用的版本是7.8.0，所以为了防止连接ES失败，要把版本号修改过成和本地一致。

xml复制代码<!-- 在pom.xml文件的properties属性下面添加： -->
<elasticsearch.version>7.8.0</elasticsearch.version>

一定要确保修改成功。

3、编写配置文件

java复制代码package com.cheng;

import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.client.RestClients;

@Configuration
public class ElasticSearchClientConfig {


    //配置RestHighLevelClient依赖到spring容器中待用
    @Bean
    public RestHighLevelClient restHighLevelClient(){
        RestHighLevelClient client = new RestHighLevelClient(
                RestClient.builder(
                        //绑定本机，端口，协议，如果是ES集群，就配置多个
                        new HttpHost("127.0.0.1",9200,"http")));
        return client;
    }
}

到这里，ElasticSearch和SpringBoot的集成就完成了，下面就是关于索引和文档API的使用。

Java REST Client

Java REST Client 有两种风格：

• Java Low Level REST Client ：用于Elasticsearch的官方低级客户端。它允许通过http与Elasticsearch集群通信。将请求编排和响应反编排留给用户自己处理。它兼容所有的Elasticsearch版本。
• Java High Level REST Client ：用于Elasticsearch的官方高级客户端。它是基于低级客户端的，它提供很多API，并负责请求的编排与响应的反编排。
• 官方更建议我们用Java High Level REST Client，它执行HTTP请求，而不是序列号的Java请求。

下面测试使用的是 Java 高级客户端。

2、索引的API操作详解

创建索引

java复制代码    //创建索引测试
    @Test
    void contextLoads() throws IOException {
        //创建索引的请求
        CreateIndexRequest request = new CreateIndexRequest("wanli");
        //执行创建索引的请求，返回一个响应
        CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);
        //打印响应
        System.out.println(response); //org.elasticsearch.client.indices.CreateIndexResponse@6ce3e00
    }

RestHighLevelClient中的所有API都接受RequestOptions，您可以使用该选项定制请求，而不会改变Elasticsearch执行请求的方式。例如，您可以在此处指定一个节点选择器来控制哪个节点接收请求。

判断索引是否存在

java复制代码    //判断索引是否存在,存在返回true，不存在返回false
    @Test
    public void test1() throws IOException {
        GetIndexRequest request = new GetIndexRequest("wanli_index");
        boolean b = client.indices().exists(request, RequestOptions.DEFAULT);
        System.out.println(b); //true
    }

删除索引

java复制代码    //删除索引
    @Test
    public void test2() throws IOException {
        DeleteIndexRequest request = new DeleteIndexRequest("wanli_index");
        AcknowledgedResponse response = client.indices().delete(request,RequestOptions.DEFAULT);
        System.out.println(response.isAcknowledged()); //返回true删除成功
    }

3、文档的API操作详解

添加文档

实体类：

java复制代码@Component
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private String name;
    private int age;
}

添加文档代码：

java复制代码    @Test
    public void test3() throws IOException {

        User user = new User("万里", 3);

        //创建请求
        IndexRequest request = new IndexRequest("wanli_index");

        request
                .id("1")  //文档id，不指定会有默认id
                .timeout(TimeValue.timeValueSeconds(1))//分片超时时间
                .source(JSON.toJSONString(user), XContentType.JSON); //将文档源设置为索引，user对象转化成json字符串

        IndexResponse response = client.index(request, RequestOptions.DEFAULT);
        System.out.println(response.toString());        //IndexResponse[index=wanli_index,type=_doc,id=1,version=1,result=created,seqNo=0,primaryTerm=1,shards={"total":2,"successful":1,"failed":0}]       

        System.out.println(response.status());//CREATED 操作状态
    }

判断文档是否存在

java复制代码    //判断文档是否存在
    @Test
    public void test4() throws IOException {
        //针对指定的索引和文档 ID 构造一个新的 get 请求
        GetRequest request = new GetRequest("wanli_index","1");
        
        String[] includes = Strings.EMPTY_ARRAY;
        String[] excludes = new String[]{"age"};//值获取 _source 中包含age的文档信息
        //fetchSourceContext指定需要返回字段的上下文,提供更加完善的过滤逻辑，主要特性为支持include、exclude和支持通篇符过滤。
        request.fetchSourceContext(new FetchSourceContext(true, includes, excludes));

        boolean b = client.exists(request, RequestOptions.DEFAULT);
        System.out.println(b); //true则存在
    }

获取文档信息

java复制代码    //获取文档信息
    @Test
    public void test5() throws IOException {
        GetRequest request = new GetRequest("wanli_index", "1");

        GetResponse response = client.get(request, RequestOptions.DEFAULT);
        System.out.println(response.toString());//{"_index":"wanli_index","_type":"_doc","_id":"1","_version":1,"_seq_no":0,"_primary_term":1,"found":true,"_source":{"age":3,"name":"万里"}}

        System.out.println(response.getSource());//获取_source：{name=万里, age=3}
        System.out.println(response.getVersion());//1
        System.out.println(response);//{"_index":"wanli_index","_type":"_doc","_id":"1","_version":1,"_seq_no":0,"_primary_term":1,"found":true,"_source":{"age":3,"name":"万里"}}
        
    }

修改文档信息

java复制代码    //修改文档信息
    @Test
    public void test6() throws IOException {
        UpdateRequest request = new UpdateRequest("wanli_index", "1");
        request.timeout("1s");
        User user = new User("神明", 18);

        //doc里面填具体的内容和文档格式
        request.doc(JSON.toJSONString(user),XContentType.JSON);

        UpdateResponse response = client.update(request, RequestOptions.DEFAULT);
        System.out.println(response.status()); //返回ok表示操作成功
    }

删除文档

java复制代码    //删除文档
    @Test
    public void test7() throws IOException {

        DeleteRequest request = new DeleteRequest("wanli_index", "1");
        request.timeout("1s");
        DeleteResponse response = client.delete(request, RequestOptions.DEFAULT);
        System.out.println(response.status());//返回ok表示操作成功
    }

批量插入文档

BulkRequest：批量请求包含有序的IndexRequest 、 DeleteRequest 和UpdateRequest ，并允许在单个批处理中执行它。 请注意，我们仅支持批量请求而不是每个项目的刷新。

java复制代码   //批量插入文档
    @Test
    public void test8() throws IOException {
        BulkRequest request = new BulkRequest();

        request.timeout("10s");

        ArrayList<User> list = new ArrayList<>();

        list.add(new User("shenming1",3));
        list.add(new User("shenming2",3));
        list.add(new User("shenming3",3));
        list.add(new User("shenming4",3));
        list.add(new User("shenming5",3));

        for (int i = 0; i < list.size(); i++) {
            request.add(
                   new IndexRequest("wanli_index")
                    .id(""+(i+1))
                    .source(JSON.toJSONString(list.get(i)),XContentType.JSON));
        }
            BulkResponse response = client.bulk(request, RequestOptions.DEFAULT);
            System.out.println(response.status()); //ok

    }

根据具体的需求调用下面的方法。

复杂查询操作

1、构建查询请求：SearchRequest request = new SearchRequest(“wanli_index”);

2、构建搜索条件：SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource();

3、将查询条件放入请求：request.source(sourceBuilder);

4、执行请求：SearchResponse response = client.search(request, RequestOptions.DEFAULT);

java复制代码@Test
public void test9() throws IOException {
    //构建查询请求
    SearchRequest request = new SearchRequest("wanli_index");

    //构建搜索条件
    SearchSourceBuilder sourceBuilder = SearchSourceBuilder.searchSource();
    
    //设置高亮     
    //HighlightBuilder highlightBuilder = new HighlightBuilder();
    //highlightBuilder.field("name");
    //highlightBuilder.preTags("<span style='color:red'>");
    //highlightBuilder.postTags("</span>");
    //searchSourceBuilder.highlighter(highlightBuilder);
    //分页：
    //sourceBuilder.from(0);
    //sourceBuilder.size(10);

    //QueryBuilders 工具类实现查询条件的构建
    //QueryBuilders.termQuery 精确查询
    //QueryBuilders.matchAllQuery() 匹配所有
    TermQueryBuilder queryBuilder = QueryBuilders.termQuery("name", "shenming1");
    sourceBuilder.query(queryBuilder);//将精确查询条件放入搜索条件
    sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS));//设置超时时间

    //将查询条件放入请求
    request.source(sourceBuilder);

    //执行请求
    SearchResponse response = client.search(request, RequestOptions.DEFAULT);
    //打印搜索命中文档结果
    System.out.println(JSON.toJSONString(response.getHits()));
    //{"fragment":true,"hits":[{"fields":{},"fragment":false,"highlightFields":{},"id":"1","matchedQueries":[],"primaryTerm":0,"rawSortValues":[],"score":1.1727202,"seqNo":-2,"sortValues":[],"sourceAsMap":{"name":"shenming1","age":3},"sourceAsString":"{\"age\":3,\"name\":\"shenming1\"}","sourceRef":{"fragment":true},"type":"_doc","version":-1}],"maxScore":1.1727202,"totalHits":{"relation":"EQUAL_TO","value":1}}


    System.out.println("====================================");
    for (SearchHit searchHit : response.getHits().getHits()) {
        System.out.println(searchHit.getSourceAsMap());//{name=shenming1, age=3}
    }

}

本文转载自: 掘金

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