File processing... first time.

Question

I am taking my program step by step.. this is the first day i learned about tokenizing and file input..
public class nameSearchEngine {
     public static void main(String[]args) throws FileNotFoundException {     
          System.out.println("Type a name to search in database :");
          Scanner console = new Scanner(System.in);
          String searchName = console.next();
          searchName = searchName.toLowerCase();  // make sure any type of casing works.
          Scanner input = new Scanner(new File("namedatabase.txt"));     
       findPerson(input, searchName);
          // Finds persons name and shows it.
               public static void findPerson(Scanner input, String searchName) {
                    while (input.hasNextLine()) {
                         String line = input.nextLine();
                         Scanner lineScan = new Scanner(line);
                         String findName = lineScan.next();
                         if (findName == searchName) {
                              System.out.println(line);
}

Answer 1

My two bobs worth...
package forums;
import java.io.Console;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.FileNotFoundException;
class NoDataFoundException extends java.lang.Exception
  private static final long serialVersionUID = 1L;
  public NoDataFoundException() { super(); }
  public NoDataFoundException(String message) { super(message); }
  public NoDataFoundException(String message, Throwable cause) { super(message, cause); }
  public NoDataFoundException(Throwable cause) { super(cause); }
class UserCanceledException extends java.lang.Exception
  private static final long serialVersionUID = 1L;
  public UserCanceledException() { super(); }
  public UserCanceledException(String message) { super(message); }
  public UserCanceledException(String message, Throwable cause) { super(message, cause); }
  public UserCanceledException(Throwable cause) { super(cause); }
public class NameSeeker
  private static final Console console = System.console();
  private static BufferedReader reader;
  public static void main(String[]args) throws FileNotFoundException {
    String dbname = args.length>=1 ? args[0] : "NameSeeker.txt";
    try {
      System.out.println((new NameSeeker(dbname)).firstLineStartingWith(ask("Enter the name to find: ")));
    } catch (NoDataFoundException e) {
      System.err.println(e.getMessage());
    } catch (UserCanceledException eaten) {
      // do nothing, just cleanup and exit the program.
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      if(reader!=null)try{reader.close();}catch(IOException e){e.printStackTrace();}
  public NameSeeker(String dbFilename) throws FileNotFoundException {
    reader = new BufferedReader(new FileReader(dbFilename));
  public String firstLineStartingWith(String target) throws NoDataFoundException, IOException  {
    target = target.toLowerCase(); // case insensitive comparison.
    String line = null;
    while ( (line=reader.readLine()) != null ) {
      if ( line.toLowerCase().startsWith(target) ) {
        return line;
    throw new NoDataFoundException("Not found: "+target);
  private static String ask(String prompt) throws UserCanceledException {
    System.out.print(prompt);
    String response = console.readLine();
    if(response==null) throw new UserCanceledException();
    response = response.trim();
    if(response.length()==0) throw new UserCanceledException();
    return response;
}Notes:
* ALLWAYS close your resources! In this case that's just the input-file-reader.
* Try to split your program up into steps... seperating input, processing, and output is a great place to start... in this case that just means three methods...
.... (a) input = read a name to find from the user
.... (b) processing = search the file for lines which start with the given name
.... (c) output = print out the line which starts
* If anything goes wrong print a diagnostic message; except
... (a) in the case the user doesn't enter anything to find, in which case we just exit silently.
... (b) in the case the name is not found print a simple "Not Found" message.
Cheers. Keith.
PS: If you hand in this code as your own your lecturer will smell a rat... but it is (IMHO) useful to see better ways of tackling simple problems which you already have had a go at yourself.