在Spring Boot 2.0中使用ElasticSearch

lyb-geek

发布于 2022-03-10 11:07:47

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发布于 2022-03-10 11:07:47

文章被收录于专栏：Linyb极客之路

演示的目标

1、使用Spring Data ElasticSearch连接并查询嵌入式ElasticSearch节点 https://spring.io/projects/spring-data-elasticsearch 2、使用Spring Data ElasticSearch连接并查询外部ElasticSearch节点 3、所有在ElasticSearch API 5.5.0中运行的东西都嵌入在Spring Boot 2.0中

演示先决条件

我们要将以下文档保存到ElasticSearch中

@Document(indexName = "dataexchangecode", type = "dataTransferCode")
public class DataTransfer {

    @Id
    private String id;

    private String dataExchangeCode;

    private String data;

    public DataTransfer() {
    }

    /**
     * @param id
     * @param dataExchangeCode
     * @param data
     */
    public DataTransfer(final String id, final String dataExchangeCode, final String data) {
        this.id = id;
        this.dataExchangeCode = dataExchangeCode;
        this.data = data;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getDataExchangeCode() {
        return dataExchangeCode;
    }

    public void setDataExchangeCode(String dataExchangeCode) {
        this.dataExchangeCode = dataExchangeCode;
    }

    public String getData() {
        return data;
    }

    public void setData(String data) {
        this.data = data;
    }

    @Override
    public String toString() {
        return this.id+
           this.dataExchangeCode+
           this.id;
    }
}

要了解indexName和参数类型，可查看如下文章

https://www.elastic.co/guide/en/elasticsearch/guide/current/index-doc.html

为了测试目的，让我们创建以下两个REST控制器来调用Spring Data ElasticSearch CRUD存储库：

@Component
@RestController
public class HomeController {

    @Autowired
    private DataTransferRepository dataTransferRepository;

    @GetMapping(value = "/prepareData")
    public String prepareESData() {
        final DataTransfer data = new DataTransfer("1", "AW_INPUT", "<XML>");
        dataTransferRepository.save(data);

        final DataTransfer data2 = new DataTransfer("2", "BSL_INPUT", "<XML>");
        dataTransferRepository.save(data2);

        return "Data saved into elastic search!";
    }

    @GetMapping(value = "/get/{id}")
    public DataTransfer getDataTransfer(@PathVariable("id") String id) {
        return dataTransferRepository.findById(id).get();
    }
}

连接并查询嵌入式ElasticSearch节点

构建本地节点时请记住，ElasticSearch API 5.x已针对指定用于构建本地ES节点的NodeBuilder类进行了更改。例如，查看如下stackoverflow的讨论。

https://stackoverflow.com/questions/35342083/nodebuilder-not-found-in-the-elasticsearch-api-application

ES文档说明：

NodeBuilder已被删除。虽然直接在应用程序中使用Node不受官方支持，但它仍然可以使用Node（Settings）构造函数构建。

下面是我所做的：

@Profile("localNode")
@Bean
public Node createLocalNode() throws NodeValidationException {
    final String tmpDir = System.getProperty("java.io.tmpdir");
    Settings.Builder elasticsearchSettings =
            Settings.builder()
                    .put("cluster.name", EsClusterName)
                    .put("path.data", new File(tmpDir, "data").getAbsolutePath())
                    .put("path.logs", new File(tmpDir, "logs").getAbsolutePath())
                    .put("transport.type","local")
                    .put("http.enabled","false")
                    .put("path.home", tmpDir);

    final Node node = new Node(elasticsearchSettings.build());
    node.start();

    return node;
}

有关节点参数列表，请查看以下文档

https://www.elastic.co/guide/en/elasticsearch/reference/2.1/modules-http.html

要使Spring Data ElasticSearch存储库正常工作，我们需要ElasticsearchTemplate：

@Profile("localNode")
@Bean(name="elasticsearchTemplate")
public ElasticsearchTemplate elasticsearchTemplate2() throws Exception {
    return new ElasticsearchTemplate(createLocalNode().client());
}

这将根据您的需要使用NodeClient启动ElasticsearchTemplate 。Definitelly要注意以下两件事：

1、NodeClient和TransportClient之间的区别 https://www.elastic.co/guide/en/elasticsearch/guide/current/transportclientversusnode_client.html 2、最重要的是，不推荐使用TransportClient https://www.elastic.co/guide/en/elasticsearch/client/java-api/master/transport-client.html

测试本地ElasticSearch节点

首先，我们需要构建项目：

$ mvn clean install

然后使用localNode spring profile运行Spring Boot 2.0应用程序：

$ java -jar -Dspring.profiles.active=localNode target/demo-0.0.1-SNAPSHOT.jar

ES本地节点应该启动了。

现在让我们测试一下，首先调用REST控制器端点将数据加载到ElasticSearch中：

curl http://localhost:8080/prepareData
Data saved into elastic search!

然后我们可以查询数据：

$ curl http://localhost:8080/get/1 {"id":"1","dataExchangeCode":"AW_INPUT","data":"<XML>"}

$ curl http://localhost:8080/get/2 {"id":"2","dataExchangeCode":"BSL_INPUT","data":"<XML>"}

好的，本地嵌入式节点工作正常！

连接并查询外部ElasticSearch节点

在这种情况下，我们不需要嵌入任何本地ES节点，我们只需要启动ES客户端。以下配置互联网：

Settings settings = Settings.builder()
                      .put("cluster.name", EsClusterName).build();
     TransportClient client = new PreBuiltTransportClient(settings);
     client.addTransportAddress(
            new InetSocketTransportAddress(
                    InetAddress.getByName(EsHost), EsPort));

好吧，嵌入在Spring Boot 2.0中的ES API不能与PreBuiltTransportClient一起使用，因为它需要Netty3Plugin，这个无法放到maven依赖项中。如果您仍然不希望 highlevel REST API ，可以还是使用TransportClientFactoryBean 委托给SpringDataTransportClient

@Profile("!localNode")
@Bean
public Client client() throws Exception {
    /**
     * PreBuiltTransportClient works fine, but requires Netty3Plugin
     * and Spring Boot offers only Netty4Plugin. Needs extra dependencies.

     Settings settings = Settings.builder()
                      .put("cluster.name", EsClusterName).build();
     TransportClient client = new PreBuiltTransportClient(settings);
     client.addTransportAddress(
            new InetSocketTransportAddress(
                    InetAddress.getByName(EsHost), EsPort));
     return client;
     */

    TransportClientFactoryBean client = new TransportClientFactoryBean();
    client.setClusterName(EsClusterName);

    client.afterPropertiesSet();

    return client.getObject();
}

当然，我们需要再次使用ElasticsearchTemplate来使Spring Data ES工作：

@Profile("!localNode")
@Bean(name = "elasticsearchTemplate")
public ElasticsearchOperations elasticsearchTemplate1() throws Exception {
    return new ElasticsearchTemplate(client());
}

准备好代码，让我们测试整个场景：

打开终端并启动外部ES服务器

$ elasticsearch

验证外部elasticsearch服务器是否正在运行：

$ curl http://localhost:9200 
{
  "name" : "NmF778a",
  "cluster_name" : "elasticsearch_tomask79",
  "cluster_uuid" : "Z0CfKNMxSNGqfkUONZ6bRg",
  "version" : {
    "number" : "6.4.2",
    "build_flavor" : "oss",
    "build_type" : "tar",
    "build_hash" : "04711c2",
    "build_date" : "2018-09-26T13:34:09.098244Z",
    "build_snapshot" : false,
    "lucene_version" : "7.4.0",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}

现在让我们使用默认的spring配置文件启动applicationn：

$ java -jar target/demo-0.0.1-SNAPSHOT.jar

然后让我们重复调用REST端点，将数据加载到ES中并查询：

curl http://localhost:8080/prepareData
Data saved into elastic search!

$ curl http://localhost:8080/get/1
{"id":"1","dataExchangeCode":"AW_INPUT","data":"<XML>"}

$ curl http://localhost:8080/get/2
{"id":"2","dataExchangeCode":"BSL_INPUT","data":"<XML>"}

连接到外部ES也可以正常工作。