产品全站检索Elasticsearch使用代码案例

以下是一个简单的使用Java语言操作Elasticsearch实现全站检索的代码案例：

import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.builder.SearchSourceBuilder;

public class ElasticsearchSearch {

    private RestHighLevelClient client;

    public ElasticsearchSearch(RestHighLevelClient client) {
        this.client = client;
    }

    public SearchResponse search(String keyword) throws IOException {
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        searchSourceBuilder.query(QueryBuilders.matchQuery("content", keyword));
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("index_name");
        searchRequest.source(searchSourceBuilder);
        return client.search(searchRequest, RequestOptions.DEFAULT);
    }

}

其中，`RestHighLevelClient`是Elasticsearch官方提供的Java客户端，`search()`方法接受一个关键词作为参数，使用`QueryBuilders.matchQuery()`方法构建查询条件，将查询请求发送至`index_name`所代表的索引，并返回`SearchResponse`对象，其中包含了搜索结果。