关于java:Elasticsearch-resthighlevelclient-基本操作

40次阅读

共计 5671 个字符,预计需要花费 15 分钟才能阅读完成。

Elasticsearch rest-high-level-client 基本操作

本篇次要解说一下 rest-high-level-client 去操作 Elasticsearch , 尽管这个客户端在后续版本中会缓缓淘汰, 然而目前大部分公司中应用 Elasticsearch 版本都是 6.x 所以这个客户端还是有肯定的理解

前置筹备

  • 筹备一个 SpringBoot 环境 2.2.11 版本
  • 筹备一个 Elasticsearch 环境 我这里是 8.x 版本
  • 引入依赖 elasticsearch-rest-high-level-client 7.4.2

1. 配置依赖

留神: 我应用的是 springboot 2.2.11 版本 , 它外部的 elasticsearch 和 elasticsearch-rest-client 都是 6.8.13 须要留神

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
       <!-- 引入 elasticsearch 7.4.2  -->
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.4.2</version>
            <exclusions>
                <exclusion>
                    <artifactId>log4j-api</artifactId>
                    <groupId>org.apache.logging.log4j</groupId>
                </exclusion>
            </exclusions>
        </dependency>

      <!-- 排除 elasticsearch-rest-client , 也可不排除 为了把 maven 抵触解决   -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.4.2</version>
            <exclusions>
                <exclusion>
                    <groupId>org.elasticsearch.client</groupId>
                    <artifactId>elasticsearch-rest-client</artifactId>
                </exclusion>
                <exclusion>
                    <artifactId>elasticsearch</artifactId>
                    <groupId>org.elasticsearch</groupId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- 不引入会导致可能 应用 springboot 的 elasticsearch-rest-client 6.8.13 -->
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-client</artifactId>
            <version>7.4.2</version>
        </dependency>

        <!-- elasticsearch 依赖 2.x 的 log4j -->
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.8.2</version>
            <!--  排除掉 log4j-api 因为 springbootstarter 中引入了 loging 模块 -->
            <exclusions>
                <exclusion>
                    <artifactId>log4j-api</artifactId>
                    <groupId>org.apache.logging.log4j</groupId>
                </exclusion>
            </exclusions>
        </dependency>

        <!-- junit 单元测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

2. 构建 RestHighLevelClient

highlevelclient 是 高级客户端 须要通过它去操作 Elasticsearch , 它底层也是要依赖 rest-client 低级客户端

@Slf4j
public class TestEsClient {

    private RestHighLevelClient client = null;
    private ObjectMapper objectMapper = new ObjectMapper();
        
    // 构建 RestHighLevelClient
    @Before
    public void prepare() {
        // 创立 Client 连贯对象
        String[] ips = {"172.16.225.111:9200"};
        HttpHost[] httpHosts = new HttpHost[ips.length];
        for (int i = 0; i < ips.length; i++) {httpHosts[i] = HttpHost.create(ips[i]);
        }
        RestClientBuilder builder = RestClient.builder(httpHosts);
        client = new RestHighLevelClient(builder);
    }
}

3. 创立索引 client.indices().create

创立索引 须要应用 CreateIndexRequest 对象 , 操作 索引基本上是 client.indices().xxx

构建 CreateIndexRequest 对象

@Test
public void test1() {CreateIndexRequest request = new CreateIndexRequest("blog1");
    try {
        CreateIndexResponse createIndexResponse =
                client.indices().create(request, RequestOptions.DEFAULT);
        boolean acknowledged = createIndexResponse.isAcknowledged();
        log.info("[create index blog :{}]", acknowledged);
    } catch (IOException e) {e.printStackTrace();
    }
}

4. 删除索引 client.indices().delete

构建 DeleteIndexRequest 对象

@Test
public void testDeleteIndex(){DeleteIndexRequest deleteIndexRequest = new DeleteIndexRequest("blog1");
    try {AcknowledgedResponse response = client.indices().delete(deleteIndexRequest, RequestOptions.DEFAULT);
        log.info("[delete index response: {}", response.isAcknowledged());
    } catch (IOException e) {e.printStackTrace();
    }

}

4. 查问索引 client.indices().get

构建 GetIndexRequest 对象

@Test
public void testSearchIndex() {GetIndexRequest request = new GetIndexRequest("blog1");
    try {
        GetIndexResponse getIndexResponse =
                client.indices().get(request, RequestOptions.DEFAULT);
        Map<String, List<AliasMetaData>> aliases = getIndexResponse.getAliases();
        Map<String, MappingMetaData> mappings = getIndexResponse.getMappings();
        Map<String, Settings> settings = getIndexResponse.getSettings();
        log.info("[aliases: {}]", aliases);
        log.info("[mappings: {}]", mappings);
        log.info("[settings: {}", settings);
    } catch (IOException e) {e.printStackTrace();
    }
}

能够依据 response 获取 aliases , mappings , settings 等等 和 Kibana 中返回的一样

5. 插入文档 client.index

插入文档 须要应用 IndexRequest 对象 , 留神 不是 InsertRequest , 不晓得为什么不这样定义 感觉会更加好了解

request.source(blogInfoJsonStr, XContentType.JSON);

@Test
public void insertDoc() {IndexRequest request = new IndexRequest();
    request.index("blog1").id("1");
    BlogInfo blogInfo =
            new BlogInfo()
                    .setBlogName("Elasticsearch 入门第一章")
                    .setBlogType("Elasticsearch")
                    .setBlogDesc("本篇次要介绍了 Elasticsearch 的根本 client 操作");
    try {
         // 提供 java 对象的 json str
        String blogInfoJsonStr = objectMapper.writeValueAsString(blogInfo);
        
        request.source(blogInfoJsonStr, XContentType.JSON);
        // 这里会抛错 起因是 我的 Elasticsearch 版本 8.x 而 应用的 restHighLevel 曾经解析不了, 因为新的 es 曾经不举荐应用
        // restHighLevel, 而应用 Elasticsearch Java API Client
        IndexResponse index = client.index(request, RequestOptions.DEFAULT);
        log.info("[Result insert doc :{} ]", index);
    } catch (IOException e) {}}

6. 查问文档 client.get

留神 getResponse.getSourceAsString() 返回文档数据

@Test
public void testSelectDoc() {GetRequest getRequest = new GetRequest();
    getRequest.index("blog1").id("1");
    try {GetResponse getResponse = client.get(getRequest, RequestOptions.DEFAULT);
        BlogInfo blogInfo =
                objectMapper.readValue(getResponse.getSourceAsString(), BlogInfo.class);
        log.info("[get doc :{}]", blogInfo);
    } catch (IOException e) {e.printStackTrace();
    }
}

7. 删除文档 client.delete

留神 删除文档 的 response 也解析不了 Elasticsearch 8.x 版本

@Test
public void testDeleteDoc() {DeleteRequest deleteRequest = new DeleteRequest();
    deleteRequest.index("blog1").id("1");
    try {
        // 这里也会抛错 和下面的一样
        DeleteResponse deleteResponse = client.delete(deleteRequest, RequestOptions.DEFAULT);
        log.info("[delete response:{} ]", deleteResponse);
    } catch (IOException e) {}}

总结

本篇次要介绍了 java 操作 Elasticsearch 的客户端 rest-high-level-client 的根本应用 , 如果你是应用 springboot 须要留神 jar 抵触问题, 后续操作 Elasticsearch 客户端 逐步变成 Elasticsearch Java API Client , 不过目前大部分还是应用 rest-high-level-client

欢送大家拜访 集体博客 Johnny 小屋
欢送关注集体公众号

正文完
 0