Elastic Spring Boot Starter

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

  <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

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

• 创建一个ElasticSearchProperties类加载配置信息

  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

  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