Solr檢索資料

在本章中，我們將討論如何使用Java Client API檢索資料。假設有一個名為sample.csv的.csv文件，其中包含以下內容。

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

可以使用post命令在核心-solr_sample下對此資料編製索引。

[yiibai@ubuntu:/usr/local/solr]$ ./post -c solr_sample sample.csv

以下是向Apache Solr索引新增文件的Java程式程式碼。將此程式碼儲存在RetrievingData.java的檔案中。

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();         
   } 
}

通過在終端中執行以下命令編譯上述程式碼 -

[yiibai@ubuntu:/usr/local/solr]$ javac RetrievingData.java
[yiibai@ubuntu:/usr/local/solr]$ java RetrievingData

執行上述命令後，將得到以下輸出。

{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}