how to use Thread in java ?
- by tiendv
Hi all
i have code use googleseach API
I want to use Thread to improve speed of my program. But i have a problem
here is code
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONObject;
import com.yahoo.search.WebSearchResult;
/**
* Simple Search using Google ajax Web Services
*
* @author Daniel Jones Copyright 2006 Daniel Jones Licensed under BSD open
* source license http://www.opensource.org/licenses/bsd-license.php
*/
public class GoogleSearchEngine extends Thread {
private String queryString;
private int maxResult;
private ArrayList<String> resultGoogleArrayList = null;
public ArrayList<String> getResultGoogleArrayList() {
return resultGoogleArrayList;
}
public void setResultGoogleArrayList(ArrayList<String> resultGoogleArrayList) {
this.resultGoogleArrayList = resultGoogleArrayList;
}
public String getQueryString() {
return queryString;
}
public void setQueryString(String queryString) {
this.queryString = queryString;
}
public int getMaxResult() {
return maxResult;
}
public void setMaxResult(int maxResult) {
this.maxResult = maxResult;
}
// Put your website here
public final static String HTTP_REFERER = "http://www.example.com/";
public static ArrayList<String> makeQuery(String query, int maxResult) {
ArrayList<String> finalArray = new ArrayList<String>();
ArrayList<String> returnArray = new ArrayList<String>();
try {
query = URLEncoder.encode(query, "UTF-8");
int i = 0;
String line = "";
StringBuilder builder = new StringBuilder();
while (true) {
// Call GoogleAjaxAPI to submit the query
URL url = new URL("http://ajax.googleapis.com/ajax/services/search/web?start=" + i + "&rsz=large&v=1.0&q=" + query);
URLConnection connection = url.openConnection();
if (connection == null) {
break;
}
// Value i to stop while or Max result
if (i >= maxResult) {
break;
}
connection.addRequestProperty("Referer", HTTP_REFERER);
BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(),"utf-8"));
while ((line = reader.readLine()) != null) {
builder.append(line);
}
String response = builder.toString();
JSONObject json = new JSONObject(response);
JSONArray ja = json.getJSONObject("responseData").getJSONArray("results");
for (int j = 0; j < ja.length(); j++) {
try {
JSONObject k = ja.getJSONObject(j);
// Break string into 2 parts: URL and Title by <br>
returnArray.add(k.getString("url") + "<br>" + k.getString("titleNoFormatting"));
}
catch (Exception e) {
e.printStackTrace();
}
}
i += 8;
}
// Remove objects that is over the max number result required
if (returnArray.size() > maxResult) {
for (int k=0; k<maxResult; k++){
finalArray.add(returnArray.get(k));
}
}
else
return returnArray;
return finalArray;
}
catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
public void run() {
// TODO Auto-generated method stub
//super.run();
this.resultGoogleArrayList = GoogleSearchEngine.makeQuery(queryString, maxResult);
System.out.println("Code run here ");
}
public static void main(String[] args)
{
Thread test = new GoogleSearchEngine();
((GoogleSearchEngine) test).setQueryString("data ");
((GoogleSearchEngine) test).setMaxResult(10);
test.start();
ArrayList<String> returnGoogleArrayList = null;
returnGoogleArrayList = ((GoogleSearchEngine) test).getResultGoogleArrayList();
System.out.print("contents of al:" + returnGoogleArrayList);
}
}
when i run it, it can run into run method but it don't excute make query methor and return null array.
when i do't use Thread it can nomal .
Can you give me the reason why ? or give a sulution
Thanks
