Added a JSON parser and a new DB connection handler and pool

src/zutil/db/MySQLConnection.java

@@ -0,0 +1,108 @@
+package zutil.db;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public class MySQLConnection {
+	Connection conn = null;
+	
+	/**
+	 * Connects to a MySQL server
+	 * 
+	 * @param url is the URL of the MySQL server
+	 * @param db is the database to connect to
+	 * @param user is the user name
+	 * @param password is the password
+	 */
+    public MySQLConnection(String url, String db, String user, String password) 
+    		throws SQLException, InstantiationException, IllegalAccessException, ClassNotFoundException{
+		Class.forName ("com.mysql.jdbc.Driver").newInstance();
+		DriverManager.setLoginTimeout(10);
+        conn = DriverManager.getConnection ("jdbc:mysql://"+url+"/"+db, user, password);
+    }
+    
+    /**
+     * Runs a query and returns the result.<br>
+     * <b>NOTE:</b> Don't forget to close the ResultSet and the Statement or it 
+     * can lead to memory leak: rows.getStatement().close();
+     * 
+     * @param sql is the query to execute
+     * @return the data that the DB returned
+     */
+    public synchronized ResultSet query(String sql) throws SQLException{
+    	Statement s = conn.createStatement ();
+    	s.executeQuery(sql);
+    	return s.getResultSet();    	
+    }
+    
+    /**
+     * Returns the first cell of the first row of the query
+     * 
+     * @param sql is the SQL query to run, preferably with the LIMIT 1 at the end
+     * @return A SQL row if it exists or else null
+     */
+    public synchronized String simpleQuery(String sql) throws SQLException{
+    	Statement s = conn.createStatement ();
+    	s.executeQuery(sql);
+    	ResultSet result = s.getResultSet();
+    	if(result.next()){
+    		String tmp = result.getString(1);
+    		result.close();
+    		return tmp;
+    	}
+    	return null;    	
+    }
+    
+    /**
+     * Runs a query in the MySQL server and returns effected rows
+     * 
+     * @param sql is the query to execute
+     * @return the number of rows effected
+     */
+    public synchronized int updateQuery(String sql) throws SQLException{
+    	Statement s = conn.createStatement ();
+    	int ret = s.executeUpdate(sql);
+    	s.close();
+    	return ret;
+    }
+    
+    /**
+     * @return the last inserted id or -1 if there was an error
+     * @throws SQLException
+     */
+    public int getLastInsertID() throws SQLException{
+    	Statement s = conn.createStatement ();
+    	s.executeQuery("SELECT LAST_INSERT_ID()");
+    	ResultSet result = s.getResultSet();
+    	if(result.next()){
+    		int tmp = result.getInt(1);
+    		result.close();
+    		return tmp;
+    	}
+    	return -1;   
+    }
+    
+    /**
+     * Runs a Prepared Statement.<br>
+     * <b>NOTE:</b> Don't forget to close the PreparedStatement or it can lead to memory leak
+     * 
+     * @param sql is the SQL query to run
+     * @return The PreparedStatement
+     */
+    public synchronized PreparedStatement prepareStatement(String sql) throws SQLException{
+    	return conn.prepareStatement(sql);
+    }
+    
+    /**
+     * Disconnects from the database
+     */
+    public synchronized void close() throws SQLException{
+    	if (conn != null){
+            conn.close ();
+        }
+    }
+}