RESTful Java Web Service For Solr

You have your Solr server set-up, now what?  You want people to be able to perform queries and have some control over what can be input, well you need a Java Web Service!  This is a short guide on how to create your Java Web Service which may not be tailored to your particular needs but you can tweak it as you please.

Set-Up

To set up the Java Web Service you will need:

• Netbeans 7 with GlassFish
• Solr Set-up and Running

Steps Involved

Project Set-Up

• Start Netbeans and Go to File→New Project→Java Web→Web Applications and then hit Next.
• Give your project a name and then hit Next
• Ensure that Glassfish is the selected server and hit Finish

HelloResource.java

• Right click the Default Package and create a new Java Class and call it HelloResource.java
• Enter the following code:
  
  

  import java.net.URL;
  import javax.ws.rs.GET;
  import javax.ws.rs.Path;
  import javax.ws.rs.Produces;
  import javax.ws.rs.QueryParam;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.net.URLConnection;
   
  /**
   *
   * @author alamil
   */
   
  //Looks for hello in the pathname
  @Path("hello")
  public class HelloResource {
   
      /**
       *
       * @param arg
       * @param rows
       * @return
       */
      @GET
      @Path("/query")     //Looks for /query in the pathname
      @Produces("text/xml")       //Returns xml
      public String hello(@QueryParam("q") String arg, @QueryParam("rows") String rows, @QueryParam("filter") String filter){
   
          //Variables
          String xmldoc = "";
          String inputLine;
   
          //If the user has not selected a number of rows to display then 50 is set to defualt
          if (rows == null) 
              rows = "50";
   
          //If the user has not selected fields to filter on then it uses the default
          if (filter == null)
              filter = "id,title";
   
          try{
   
              //Trys to connect to the Solr Server with the query
              URL solr = new URL("http://localhost:8080/solr/select?q=url:(" + arg.replaceAll(" ","%20") 
                      + ")^25%20text:(" + arg.replaceAll(" ","%20") + ")&fl=" + filter + "&rows=" + rows);
   
              URLConnection yc = solr.openConnection();
   
              //Reads the returned xml file from the server
              BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
   
              while ((inputLine = in.readLine()) != null){ 
                      xmldoc = xmldoc + inputLine;
              }
   
              //Close the file
              in.close();
   
              //Return the xml document (Replacing the %20's with spaces)
              return xmldoc.replaceAll("%20", " ");
          }catch (Exception e){
                  return "Exception";
          }
      }
  }

RESTConfig.java

• Right click the Default Package and create a new Java Class and call it RESTConfig.java
• Enter the following code:
  
  

  import javax.ws.rs.core.Application;
  import javax.ws.rs.ApplicationPath;
  /**
   *
   * @author alamil
   */
  @ApplicationPath("SearchInt")
  public class RESTConfig extends Application {
   
  }

Testing

• Go to Run→Run Project and your server should start
• A browser window will open to the index.html page that is there which you can tweak and edit to your own liking
• Start your solr server
• In your browser, Navigate to:
  localhost:8080/HelloRest/SearchInt/hello/query?q=[query term]&filter=[filter term]&rows=[rows]

• The input parameters set up are:
  1. q=… : representing the keywords in the query
  2. rows=… : representing the number of rows you wish to have returned
  3. filter=… :representing which fields are displayed to the user

Your server and Solr server may be running from the same port which can cause problems