Apache Solr 简明教程

Apache Solr - Retrieving Data

在本章中，我们将讨论如何使用 Java Client API 检索数据。假设我们有一个名为 sample.csv 的 .csv 文档，其中包含如下内容。

001,9848022337,Hyderabad,Rajiv,Reddy
002,9848022338,Kolkata,Siddarth,Battacharya
003,9848022339,Delhi,Rajesh,Khanna

你可以使用 post 命令在名为 sample_Solr 的核心下索引此数据。

[Hadoop@localhost bin]$ ./post -c Solr_sample sample.csv

以下 Java 程序用于向 Apache Solr 索引中添加文档。将此代码保存到名为 RetrievingData.java 的文件中。

import java.io.IOException;

import org.apache.Solr.client.Solrj.SolrClient;
import org.apache.Solr.client.Solrj.SolrQuery;
import org.apache.Solr.client.Solrj.SolrServerException;
import org.apache.Solr.client.Solrj.impl.HttpSolrClient;
import org.apache.Solr.client.Solrj.response.QueryResponse;
import org.apache.Solr.common.SolrDocumentList;

public class RetrievingData {
   public static void main(String args[]) throws SolrServerException, IOException  {
      //Preparing the Solr client
      String urlString = "http://localhost:8983/Solr/my_core";
      SolrClient Solr = new HttpSolrClient.Builder(urlString).build();

      //Preparing Solr query
      SolrQuery query = new SolrQuery();
      query.setQuery("*:*");

      //Adding the field to be retrieved
      query.addField("*");

      //Executing the query
      QueryResponse queryResponse = Solr.query(query);

      //Storing the results of the query
      SolrDocumentList docs = queryResponse.getResults();
      System.out.println(docs);
      System.out.println(docs.get(0));
      System.out.println(docs.get(1));
      System.out.println(docs.get(2));

      //Saving the operations
      Solr.commit();
   }
}

通过在终端中执行以下命令编译上述代码 -

[Hadoop@localhost bin]$ javac RetrievingData
[Hadoop@localhost bin]$ java RetrievingData

执行以上命令，您将获得以下输出。

{numFound = 3,start = 0,docs = [SolrDocument{id=001, phone = [9848022337],
city = [Hyderabad], first_name = [Rajiv], last_name = [Reddy],
_version_ = 1547262806014820352}, SolrDocument{id = 002, phone = [9848022338],
city = [Kolkata], first_name = [Siddarth], last_name = [Battacharya],

_version_ = 1547262806026354688}, SolrDocument{id = 003, phone = [9848022339],
city = [Delhi], first_name = [Rajesh], last_name = [Khanna],

_version_ = 1547262806029500416}]}

SolrDocument{id = 001, phone = [9848022337], city = [Hyderabad], first_name = [Rajiv],
last_name = [Reddy], _version_ = 1547262806014820352}

SolrDocument{id = 002, phone = [9848022338], city = [Kolkata], first_name = [Siddarth],
last_name = [Battacharya], _version_ = 1547262806026354688}

SolrDocument{id = 003, phone = [9848022339], city = [Delhi], first_name = [Rajesh],
last_name = [Khanna], _version_ = 1547262806029500416}