ElasticSearch RestHighLevelClient 教程（二） 操作index

前言

官方推荐的RestHighLevelClient在网络上相关文档较少，因此很多坑都需要通过自己看官方文档，源代码解决。因此这系列文章就是为了解决这些文档提及不全的部分，如果有文章没提到的部分，欢迎一起交流。

这篇就关于使用RestClient操作索引，内容就是解决问题的实例。同样，一切版本以5.6.0为准。其他升级版本新的api不属此列。

正文

问题根源

​ 由于使用RestHighLevelClient（后称为rhlClient）时，进行Index操作，所有IndexRequest都会校验Index，type，source，contentType不为空。

 // 校验源码
if (type == null) {
            validationException = addValidationError("type is missing", validationException);
        }
        if (source == null) {
            validationException = addValidationError("source is missing", validationException);
        }
        if (contentType == null) {
            validationException = addValidationError("content type is missing", validationException);
        }

​ 所以，如果只创建索引时一定会遇到校验抛出异常，而是否有其他方法绕过校验不得而知，而本人的方法是使用老版本RestClient直接操作。虽然在封装上会比rhlClient简陋，但是同时具备了更高的灵活性。

操作实例

1. 创建索引

   首先给出rest api 操作的格式：

   因为整合了ik中文分词器，所以“analyzer”: “ik_max_word”此处参考安装配置ik分词器

   /PUT {{host}}:{{port}}/demo
   {
   "mappings":{
       "doc":{
           "properties":{
               "title":{
                   "type":"text",
                    "analyzer": "ik_max_word"
               },
               "content":{
                   "type":"text",
                    "analyzer": "ik_max_word"
               },
               "uniqueId":{
                   "type":"keyword",
                   "index":"not_analyzed"
               },
               "created":  {
                   "type":   "date", 
                   "format": "strict_date_optional_time||epoch_millis"
               }
           }
       }
   },
   "settings":{
           "number_of_shards":3,
           "number_of_replicas":1
   }
   }

   @Test
   public void indexTest() {
       try {
               // 借助indexRequest的json拼接工具
           IndexRequest indexRequest = new IndexRequest();
           XContentBuilder builder = JsonXContent.contentBuilder()
                   .startObject()
                       .startObject("mappings")
                           .startObject("doc")
                               .startObject("properties")
                                   .startObject("title")
                                       .field("type","text")
                                       .field("analyzer","ik_max_word")
                                   .endObject()
                                   .startObject("content")
                                       .field("type","text")
                                       .field("index","analyzed")
                                       .field("analyzer","ik_max_word")
                                   .endObject()
                                   .startObject("uniqueId")
                                       .field("type","keyword")
                                       .field("index","not_analyzed")
                                   .endObject()
                                   .startObject("created")
                                       .field("type","date")
                                       .field("format","strict_date_optional_time||epoch_millis")
                                   .endObject()
                               .endObject()
                           .endObject()
                       .endObject()
                       .startObject("settings")
                           .field("number_of_shards",3)
                           .field("number_of_replicas",1)
                       .endObject()
                   .endObject();
           indexRequest.source(builder);
               // 生成json字符串
           String source = indexRequest.source().utf8ToString();
           HttpEntity entity = new NStringEntity(source, ContentType.APPLICATION_JSON);
          // 使用RestClient进行操作 而非rhlClient
               Response response = client.performRequest("put", "/demo", Collections. emptyMap(),
                   entity);
           System.out.println(response);
       } catch (IOException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       }
   
   }

   // 结果
   /GET {{host}}:{{port}}/demo
   {
      "demo": {
          "aliases": {},
          "mappings": {
              "doc": {
                  "properties": {
                      "content": {
                          "type": "text",
                          "analyzer": "ik_max_word"
                      },
                      "created": {
                          "type": "date"
                      },
                      "title": {
                          "type": "text",
                          "analyzer": "ik_max_word"
                      },
                      "uniqueId": {
                          "type": "keyword"
                      }
                  }
              }
          },
          "settings": {
              "index": {
                  "creation_date": "1515043588766",
                  "number_of_shards": "3",
                  "number_of_replicas": "1",
                  "uuid": "8a7GoGgwQFyr8s3Ehs8HSA",
                  "version": {
                      "created": "5060099"
                  },
                  "provided_name": "demo"
              }
          }
      }
   }

   可以看到映射和设置已完成配置。

   如果有其他需要的配置，可以参考官网api，然后只要拼接对应的json字符串，使用RestClient请求即可。

2. 创建类型映射

   首先必须保证索引存在，才能创建类型映射。

   /POST {{host}}:{{port}}/newspaper/sports/_mapping
   {
   "properties":{
       "content":{
           "type":"text",
           "analyzer":"ik_max_word",
           "index":"analyzed"
       }
   }
   }

   @Test
   public void indexTest2() {
       try {
           IndexRequest indexRequest = new IndexRequest();
           XContentBuilder builder = JsonXContent.contentBuilder()
                   .startObject()
                       .startObject("properties")
                           .startObject("content")
                               .field("type","text")
                               .field("analyzer","ik_max_word")
                               .field("index","analyzed")
                           .endObject()
                       .endObject()
                   .endObject();
           indexRequest.source(builder);
           String source = indexRequest.source().utf8ToString();
           HttpEntity entity = new NStringEntity(source, ContentType.APPLICATION_JSON);
           Response response = client.performRequest("post", "/newspaper/sports/_mapping", Collections. emptyMap(),
                   entity);
           System.out.println(response);
       } catch (IOException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       }
   }

   /GET {{host}}:{{port}}/newspaper
   {
      "newspaper": {
          "aliases": {},
          "mappings": {
              "sports": {
                  "properties": {
                      "content": {
                          "type": "text",
                          "analyzer": "ik_max_word"
                      }
                  }
              }
          },
          "settings": {
              "index": {
                  "creation_date": "1515045134942",
                  "number_of_shards": "5",
                  "number_of_replicas": "1",
                  "uuid": "HZ7b3ey1TNu2erzTtG-1Fg",
                  "version": {
                      "created": "5060099"
                  },
                  "provided_name": "newspaper"
              }
          }
      }
   }

   创建sports类型映射成功。主要点还是在于拼接json字符串。

3. 查看索引是否存在

   public boolean checkIndexExist(String index) throws IOException {
       Response response = restClient.performRequest("HEAD", index);
       boolean exist = response.getStatusLine().getReasonPhrase().equals("OK");
       return exist;
   }

4. 删除索引

   /DELETE {{host}}:{{port}}/newspaper/

   Response response = restClient.performRequest("DELETE", indexName);

总结

​ 以上便是对索引的大部分操作，可以看到绝大部分都是通过restClient绕过rhlClient的空类型检测。所以如果还有其他对索引的需求，也可以尝试使用IndexRequest的Json拼接工具，拼接好Json字符串后，使用restClient发出请求。