此Starter使用的版本

  • elasticsearch-rest-high-level-client 7.2.0
  • elasticsearch-rest-client 7.2.0
  • elasticsearch
  • elastic 7.*

为什么写这个Starter

公司的Elastic版本还是6.x，而且使用的transportClient，作为客户端。一则再升级版本会面临客户端不支持，另外一个官方也已经不再推荐使用transportClient，写这个Starter练练手，另外有备无患。

如何写一个SpringBoot的Starter

写一个Starter相对来说其实很简单，按约定格式引入依赖，加入一个spring.factories文件即可。

  • 创建一个Maven项目，名称使用xxx-spring-boot-starter命名，以便和官方的Starter区分开，比如au92-elastic-spring-boot-starter

  • POM引用，实际需要用到的依赖包只有两个

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    <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-configuration-processor</artifactId>
    <optional>true</optional>
</dependency>

  • resources目录创建文件夹META-INF，新建一个spring.factories文件

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    org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.au92.common.elastic.ElasticSearchAutoConfiguration

  • 创建一个ElasticSearchProperties类加载配置信息

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    package com.au92.common.elastic;

import lombok.Data;
import org.apache.commons.lang3.StringUtils;
import org.springframework.boot.context.properties.ConfigurationProperties;

/**
* @author: p_x_c
*/
@Data
@ConfigurationProperties(prefix = "elasticsearch")
public class ElasticSearchProperties {
    /**
    * es集群地址，多个用英文逗号分开
    */
    private String clusterNodes = "http://127.0.0.1:9200";
    /**
    * es 用户名
    */
    private String userName = StringUtils.EMPTY;

    /**
    * es 用户密码
    */
    private String password = StringUtils.EMPTY;

    /**
    * 默认es索引名称
    */
    private String index = "default";
}

  • 新建 ElasticSearchAutoConfiguration 用来将配置自动加载进来

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    package com.au92.common.elastic;

import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Arrays;
import java.util.Objects;
import java.util.stream.Collectors;

import static org.springframework.beans.factory.config.ConfigurableBeanFactory.SCOPE_PROTOTYPE;

/**
* @author: p_x_c 
*/
@Slf4j
@Configuration
@EnableConfigurationProperties(ElasticSearchProperties.class)
public class ElasticSearchAutoConfiguration implements DisposableBean {
    private RestHighLevelClient client;

    @Resource
    private ElasticSearchProperties properties;

    @Override
    public void destroy() throws Exception {
        log.info("销毁ES连接");
        if (client != null) {
            client.close();
        }
    }

    /**
    * 创建client
    *
    * @return
    * @throws IOException
    */
    @Bean
    @ConditionalOnMissingBean(RestHighLevelClient.class)
    public RestHighLevelClient client() throws IOException {
        if (!Objects.equals(null, client)) {
            log.warn("client对象没有正确关闭");
            client.close();
        }
        RestClientBuilder builder = RestClient.builder(setting());
        setConnectTimeOutConfig(builder);
        setMutiConnectConfig(builder);
        client = new RestHighLevelClient(builder);
        return client;
    }

    /**
    * Elastic Service
    *
    * @return
    */
    @Bean
    @Scope(value = SCOPE_PROTOTYPE)
    @ConditionalOnMissingBean(IElasticSearchService.class)
    public IElasticSearchService service() {
        return new ElasticSearchServiceImpl();
    }

    /**
    * 解析配置文件
    *
    * @return
    */
    private HttpHost[] setting() {
        return Arrays.stream(properties.getClusterNodes().split(ElasticConstant.CLUSTER_SPLIT))
                .map(x -> {
                    String[] addressPortPairs = x.split(ElasticConstant.SCHEME_SPLIT);
                    String schemeName = addressPortPairs[0].toLowerCase();
                    String hostname = addressPortPairs[1].substring(2);
                    Integer port = Integer.valueOf(addressPortPairs[2]);
                    return new HttpHost(hostname, port, schemeName);
                })
                .collect(Collectors.toList())
                .toArray(new HttpHost[0]);

    }

    /**
    * 超时设置
    *
    * @param builder
    */
    private void setConnectTimeOutConfig(RestClientBuilder builder) {
        builder.setRequestConfigCallback(requestConfigBuilder -> {
            requestConfigBuilder.setConnectTimeout(ElasticConstant.CONNECT_TIME_OUT)
                    .setSocketTimeout(ElasticConstant.SOCKET_TIME_OUT)
                    .setConnectionRequestTimeout(ElasticConstant.CONNECTION_REQUEST_TIME_OUT);
            return requestConfigBuilder;
        });
    }

    /**
    * 并发连接数设置
    *
    * @param builder
    */
    private void setMutiConnectConfig(RestClientBuilder builder) {
        builder.setHttpClientConfigCallback(httpClientBuilder -> {
            httpClientBuilder.setMaxConnTotal(ElasticConstant.MAX_CONNECT_NUM)
                    .setMaxConnPerRoute(ElasticConstant.MAX_CONNECT_PER_ROUTE);
            return httpClientBuilder;
        });
    }
}

抛开其他业务相关的逻辑，一个Spring Boot的Starter已经可以算完成了。

用到的其他工具类和一些操作类

https://gist.github.com/Chairo/1b0d06d45e5155b134b7b43abb3d84f6