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

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.<String, String> 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。

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.<String, String> 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。

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;
}

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。