java 设置es字段是个completion suggest field

实现 Java 设置 ES 字段为 Completion Suggest Field

1. 简介

在本文中，我将向你介绍如何使用 Java 在 Elasticsearch (ES) 中设置 Completion Suggest 字段。Completion Suggest 字段是一种特殊的字段类型，用于实现自动补全功能。通过设置 Completion Suggest 字段，用户可以在输入搜索关键字时得到实时的自动补全建议。

2. 实现步骤

下面是实现该功能的步骤总结：

3. 详细步骤

3.1 创建索引

首先，我们需要创建一个新的索引来存储数据。可以使用 Elasticsearch 的 Java API 创建索引。以下是创建索引的代码示例：

import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.client.indices.CreateIndexRequest;
import org.elasticsearch.client.indices.CreateIndexResponse;

RestHighLevelClient client = new RestHighLevelClient();

CreateIndexRequest request = new CreateIndexRequest("my_index");
CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT);

以上代码创建了一个名为 "my_index" 的索引。

3.2 定义映射

在索引中定义一个新的映射，指定字段的类型为 Completion。Completion Suggest 字段使用了一种特殊的数据结构，用于高效地实现自动补全功能。以下是定义映射的代码示例：

import org.elasticsearch.client.indices.PutMappingRequest;
import org.elasticsearch.client.indices.PutMappingResponse;

PutMappingRequest request = new PutMappingRequest("my_index");
request.type("_doc");

String mapping = "{\"properties\": {\"suggest_field\": {\"type\": \"completion\"}}}";

request.source(mapping, XContentType.JSON);

PutMappingResponse response = client.indices().putMapping(request, RequestOptions.DEFAULT);

以上代码定义了一个名为 "suggest_field" 的 Completion Suggest 字段。

3.3 添加文档

现在，我们可以向索引中添加包含 Completion Suggest 字段的文档。以下是添加文档的代码示例：

import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.index.IndexResponse;

IndexRequest request = new IndexRequest("my_index", "_doc", "1");
String json = "{\"suggest_field\": {\"input\": [\"apple\", \"banana\", \"cherry\"]}}";
request.source(json, XContentType.JSON);

IndexResponse response = client.index(request, RequestOptions.DEFAULT);

以上代码添加了一个名为 "suggest_field" 的文档，其中包含了三个输入项 "apple", "banana", "cherry"。

3.4 查询建议

最后，我们可以使用查询语句来获取自动补全建议。以下是查询建议的代码示例：

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.SuggestBuilders;
import org.elasticsearch.search.suggest.completion.CompletionSuggestion;

SearchRequest request = new SearchRequest("my_index");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();

String prefix = "a";
CompletionSuggestionBuilder suggestionBuilder = SuggestBuilders.completionSuggestion("suggest_field").prefix(prefix);

searchSourceBuilder.suggest(new SuggestBuilder().addSuggestion("my-suggestion", suggestionBuilder));
request.source(searchSourceBuilder);

SearchResponse response = client.search(request, RequestOptions.DEFAULT);
Suggest suggest = response.getSuggest();

CompletionSuggestion completionSuggestion = suggest.getSuggestion("my-suggestion");
List<CompletionSuggestion.Entry.Option> options = completionSuggestion.getOptions();

for (CompletionSuggestion.Entry.Option option : options) {
    System.out.println(option.getText().toString());
}

以上代码将根据输入的前缀 "a" 获取所有以此前缀开头的自动补全建议项。

4. 总结

在本文中，我向你演示了如何使用 Java 在 Elasticsearch 中设置 Completion Suggest 字段。通过按照上述步骤，你可以实现自动补全功能，并为用户提供实时的搜索建议。希