Class conn
import java.sql.*;
import java.util.ArrayList;
import java.util.Properties;
class conn
{
/* the default framework is embedded*/
private String framework = "embedded";
private String driver = "org.apache.derby.jdbc.EmbeddedDriver";
private String protocol = "jdbc:derby:";
public void go(int link_id,int word_id,String link ,String title,String Snippet)
{
System.out.println("DBworks starting in " + framework + " mode");
loadDriver();
Connection conn = null;
ArrayList statements = new ArrayList(); // list of Statements, PreparedStatements
PreparedStatement psInsert = null;
PreparedStatement psUpdate = null;
Statement s = null;
ResultSet rs = null;
try
{
Properties props = new Properties();
props.put("user", "user1");
props.put("password", "user1");
String dbName = "crawler";
conn = DriverManager.getConnection(protocol + dbName
+ ";create=true", props);
System.out.println("Connected to and created database " + dbName);
conn.setAutoCommit(false);
s = conn.createStatement();
statements.add(s);
rs = s.executeQuery("SELECT link_id,word_id,title ,snippet,link FROM links ORDER BY link_id");
if (!rs.next())
{
s.execute("create table links(link_id int,word_id int,link varchar(80),title varchar(40), snippet varchar(150))");
System.out.println("Created table links");
}
psInsert = conn.prepareStatement("insert into links values (?, ? ,? ,?,?)");
statements.add(psInsert);
psInsert.setInt(1,1);
psInsert.setInt(2,2);
psInsert.setString(3, "qwerty");
psInsert.setString(4, "qwerty");
psInsert.setString(5, "qwerty");
psInsert.executeUpdate();
System.out.println("Inserted qwerty");
rs = s.executeQuery("SELECT link_id,word_id,title ,snippet,link FROM links ORDER BY link_id");
boolean failure = false;
int number;
if (!rs.next())
{
failure = true;
reportFailure("No Data In Database");
}
if ((number = rs.getInt(1)) != 1)
{
failure = true;
reportFailure(
"Wrong row returned, expected link_id=1, got " + number);
}
if (!failure) {
System.out.println("Verified the rows");
}
s.execute("drop table links");
System.out.println("Dropped table links");
conn.commit();
System.out.println("Committed the transaction");
if (framework.equals("embedded"))
{
try
{
DriverManager.getConnection("jdbc:derby:;shutdown=true");
}
catch (SQLException se)
{
if (( (se.getErrorCode() == 50000)&& ("XJ015".equals(se.getSQLState()) )))
{
System.out.println("Derby shut down normally");
}
else {
System.err.println("Derby did not shut down normally");
printSQLException(se);
}
}
}
}
catch (SQLException sqle)
{
printSQLException(sqle);
} finally {
// release all open resources to avoid unnecessary memory usage
// ResultSet
try {
if (rs != null) {
rs.close();
rs = null;
}
} catch (SQLException sqle) {
printSQLException(sqle);
}
// Statements and PreparedStatements
int i = 0;
while (!statements.isEmpty()) {
// PreparedStatement extend Statement
Statement st = (Statement)statements.remove(i);
try {
if (st != null) {
st.close();
st = null;
}
} catch (SQLException sqle) {
printSQLException(sqle);
}
}
//Connection
try {
if (conn != null) {
conn.close();
conn = null;
}
} catch (SQLException sqle) {
printSQLException(sqle);
}
}
}
private void loadDriver() {
try {
Class.forName(driver).newInstance();
System.out.println("Loaded the appropriate driver");
} catch (ClassNotFoundException cnfe) {
System.err.println("\nUnable to load the JDBC driver " + driver);
System.err.println("Please check your CLASSPATH.");
cnfe.printStackTrace(System.err);
} catch (InstantiationException ie) {
System.err.println(
"\nUnable to instantiate the JDBC driver " + driver);
ie.printStackTrace(System.err);
} catch (IllegalAccessException iae) {
System.err.println(
"\nNot allowed to access the JDBC driver " + driver);
iae.printStackTrace(System.err);
}
}
private void reportFailure(String message) {
System.err.println("\nData verification failed:");
System.err.println('\t' + message);
}
public static void printSQLException(SQLException e)
{
while (e != null)
{
System.err.println("\n----- SQLException -----");
System.err.println(" SQL State: " + e.getSQLState());
System.err.println(" Error Code: " + e.getErrorCode());
System.err.println(" Message: " + e.getMessage());
e = e.getNextException();
}
}
}
class crawler with main class
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.net.*;
import java.io.*;
import javax.swing.*;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class Crawler extends conn
{
public static void main(String [] args)
{
JFrame frame = new EditorPaneFrame();
frame.show();
}
}
class EditorPaneFrame extends JFrame
{
conn connection = new conn();
private JTextField url;
private JButton loadButton;
private JButton backButton;
private JEditorPane editorPane;
private Stack urlStack = new Stack();
public EditorPaneFrame()
{
setTitle("Web Crawler");
setSize(600,400);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
} );
// set up text field and load button for typing in URL
url = new JTextField(30);
loadButton = new JButton("Search");
loadButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
try
{
String search = "https://www.googleapis.com/customsearch/v1?key=YPUR-GOOGLE-API-KEY&cx=013036536707430787589:_pqjad5hr1a&q="+url.getText()+"&alt=json";
URL url = new URL(search);
URLConnection link = url.openConnection();
BufferedReader reader = new BufferedReader( new InputStreamReader(link.getInputStream()));
Pattern linkPattern = Pattern.compile("[\"]link[\"]:.*");
Pattern titlePattern = Pattern.compile("[\"]title[\"]:.*");
Pattern snippetPattern = Pattern.compile("[\"]snippet[\"]:.*");
String line;
String newlink;
String title;
String snippet;
while ((line =reader.readLine()) != null)
{ Matcher l = linkPattern.matcher(line);
Matcher t =titlePattern.matcher(line);
Matcher s = snippetPattern.matcher(line);
while(l.find())
{ newlink=l.group();
newlink=newlink.replaceAll("[\"]link[\"]: [\"]", "");
System.out.println(newlink);
}
while(t.find())
{ title=t.group();
title=title.replaceAll("[\"]title[\"]: [\"]", "");
System.out.println(title);
}
while(s.find())
{ snippet=s.group();
snippet=snippet.replaceAll("[\"]snippet[\"]: [\"]", "");
System.out.println(snippet);
}
}
reader.close();
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
};
});
// set up back button and button action
backButton = new JButton("Back");
backButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
if(urlStack.size()<=1) return;
try
{
urlStack.pop();
String urlString = (String)urlStack.peek();
url.setText(urlString);
editorPane.setPage(urlString);
}
catch(IOException e)
{
editorPane.setText("Error : " +e);
}
}
});
editorPane = new JEditorPane();
editorPane.setEditable(false);
Container contentPane = getContentPane();
contentPane.add(new JScrollPane(editorPane), "Center");
JPanel panel = new JPanel();
panel.add(new JLabel("Search Term"));
panel.add(url);
panel.add(loadButton);
panel.add(backButton);
contentPane.add(panel,"South");
}
}
