[ElasticSearch]使用 java API 进行CRUD操作

矫情吗；* 2021-09-16 04:02 352阅读 0赞

[https://blog.csdn.net/lionel\_fengj/article/details/78345741][https_blog.csdn.net_lionel_fengj_article_details_78345741]

本篇文章将介绍怎样使用 java 对 ElasticSearch 进行操作。   
首先需要建立一个 maven 项目，这里不再赘述。   
1.在maven 的 pom.xml文件中需要引入以下几个 jar 包

<dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>5.6.3</version>
    </dependency>
    <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.9.1</version>
    </dependency>
    <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.9.1</version>
    </dependency>

2.在 resources 目录下添加log4j2.properties文件

appender.console.type = Console
    appender.console.name = console
    appender.console.layout.type = PatternLayout
    
    rootLogger.level = info
    rootLogger.appenderRef.console.ref = console

3.使用TransportClient连接 ElasticSearch。

Settings settings = Settings.builder().put("cluster.name", "leo").build();
    TransportClient client = new PreBuiltTransportClient(settings). addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("***.***.***.***"), 9300));
    //***.***.***.*** 表示 ip 地址，本地的话，可以使用 localhost，9300是默认的 api 访问接口

4.创建索引   
使用 json文件来创建索引，生成 json 文件的方式有多种，字符串格式、利用 Map、利用jackson 序列化 beans 到 json、使用 ElasticSearch helps生成(我使用的方式，其它方式实现可参看[官方文档][Link 1])

IndexResponse response = client.prepareIndex("books", "book", "1")
                            .setSource(jsonBuilder().
                                    startObject()
                                    .field("book_name", "ElasticSearch入门")
                                    .field("author", "张三")
                                    .field("publish_time", "207-09-09")
                                   .endObject())
                            .get();

5.获取索引

GetResponse getResponse = client.prepareGet("books", "book", "1").execute().actionGet();
            System.out.println(getResponse.getSourceAsString());

6.更新索引

UpdateRequest updateRequest = new UpdateRequest();
    updateRequest.index("books");
    updateRequest.type("book");
    updateRequest.id("1");
    updateRequest.doc(jsonBuilder().startObject().field("author", "李四").endObject());
    try {
        client.update(updateRequest).get();
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }

运行后发现作者从“张三”更新为“李四”了。   
7.删除索引

DeleteResponse response = client.prepareDelete("books", "book", "1").get();

索引被删除。

[https_blog.csdn.net_lionel_fengj_article_details_78345741]: https://blog.csdn.net/lionel_fengj/article/details/78345741
[Link 1]: https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/java-docs-index.html#java-docs-index-generate-beans