Reading data from a file and storing into array of strings problem

[Mohit G Gupta]

 


import java.io.*;
import java.util.*;

public class DVDInfo
{
	String title;
	String genre;
	String leadActor;
	DVDInfo(){}
	DVDInfo(String t,String g,String a)
	{
		title=t;
		genre=g;
		leadActor=a;
	}
	public String toString()
	{
		return title+""+genre+""+leadActor+"\n";
	}
	

	public static void main(String arg[]) throws IOException
	{ 
		  String s;
		  
	
	//String []abc1=new String[100];
//	String abc3="aas Aaa / aaa";
	//String []abc2=abc3.split("\\s");
	//for(String ee:abc2)
	//{System.out.println("wsdS"+ee);
	//}

String[] abc1=null;
		File abc=new File("movies.txt");
		abc.createNewFile();
		System.out.println(abc.createNewFile());
		FileReader fr=new FileReader(abc);
		BufferedReader br=new BufferedReader(fr);
		while((s=br.readLine())!=null){
	

 //what code should i put here so that abc[0],abc[1],abc[2] stores the first line of movies.txt
	 //and abc[3] to abc[5] stores the second line of movies.txt asnd so on....
	
		}
			System.out.println(abc1[0]);
			new DVDInfo(abc1[0],abc1[1],abc1[2]);
			//System.out.println(abc1.length);
				
	}
	
}

   

movies.txt

  
Donnie Darko/sci-fi/Gyllenhall, Jake
Raiders of the Lost Ark/action/Ford, Harrison
2001/sci-fi/??
Caddy Shack/comedy/Murray, Bill
Star Wars/sci-fi/Ford, Harrison
Lost in Translation/comedy/Murray, Bill
Patriot Games/action/Ford, Harrison

  

what code should i put here so that abc[0],abc[1],abc[2] stores the first line of movies.txt
and abc[3] to abc[5] stores the second line of movies.txt asnd so on....


i tried the follwing code in the while loop but it doesnot work

    
for(String ab:abc1)
{ab=s.split("\");}  

error
DVDInfo.java:54: incompatible types
found : java.lang.String[]
required: java.lang.String
{ab=s.split("/");}
^
1 error


tell me the code to store data from file into array of strings

[Rajeev Rnair]

Hi Mohit, I used a Scanner for parsing. Please see my code ( I was lazy to put any comments there Sorry about that ) The parsing logic is in readDVDFile() method.

import java.util.List;
import java.util.ArrayList;
import java.util.Collections;

import java.io.File;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;
import java.util.Comparator;

public class DVDTest {
	public static void main(String[] args) {
		List<DVDInfo> l = new DVDList().getListofDVD();
		Collections.sort(l);
		System.out.println(l);
		GenreSort gs = new GenreSort();
		Collections.sort(l, gs);
		System.out.println(l);
		ActorSort as = new ActorSort();
		Collections.sort(l, as);
		System.out.println(l);
	}
}

class DVDList{
	private String fileName = "dvd.txt";
	private List<DVDInfo> dvdList = new ArrayList<DVDInfo> ();
	DVDList(){
		super();
		readDVDFile();
	}
	
	DVDList(String f) {
		super();
		this.fileName = f;
		readDVDFile();
	}
	
	public List<DVDInfo> getListofDVD() {
		return  this.dvdList;
	}
	
	 private void readDVDFile() {
		Scanner sc;
		File f = new File(fileName);
		FileReader fr = null;
		BufferedReader br = null;
		try {
			fr = new FileReader(f);
			br = new BufferedReader(fr);
			String line = "" ;
			String[] dvdInfo = new String[3];
			while ((line = br.readLine()) != null) {
				sc = new Scanner(line);
				sc.useDelimiter("/");
				int i=0;
				while (sc.hasNext())
					dvdInfo[i++]= sc.next();
				this.dvdList.add(new DVDInfo(dvdInfo[0], dvdInfo[1], dvdInfo[2]));
			}
		} catch (FileNotFoundException ex) {
			System.out.println("FEX " + ex.getMessage());
		} catch (IOException ex) {
			System.out.println("IOEX " + ex.getMessage());
		} finally {
			try {
				fr.close();
			} catch (IOException ex) {
				System.out.println("IOEX " + ex.getMessage());
			}
		}
		
	}	
}

class GenreSort implements Comparator<DVDInfo> {
	public int compare(DVDInfo d1, DVDInfo d2) {
		return d1.genre.compareTo(d2.genre); 
	}
}

class ActorSort implements Comparator<DVDInfo> {
	public int compare(DVDInfo d1, DVDInfo d2) {
		return d1.leadActor.compareTo(d2.leadActor); 
	}
}

class DVDInfo implements Comparable<DVDInfo>{
	String title;
	String genre;
	String leadActor;
	
	public DVDInfo(String t, String g, String l) {
		this.title = t;
		this.genre = g;
		this.leadActor = l;
	}
	
	public String toString() {
		return title + "/" + genre +  "/" + leadActor;
	}	
	
	public int compareTo(DVDInfo d) {
		return this.title.compareTo(d.title);
	}
}

[Mohit G Gupta]

how to use split method of string class in this case instead of scanner ?

[Pradeep Kr]

Problem with array is you can not have dynamically increasing array. You need to specify size, when you initiate array.
In your example, I am assuming you don;t know how many DVDInfo are there in your movies.txt file. With minimum changes to your code, Here is what i think should work.

This is the block of code I changed

ArrayList<String> list = new ArrayList<String>();  
while ((s = br.readLine()) != null) {  
     String[] arr = s.split("/");  
     list.add(arr[0]);  
     list.add(arr[1]);  
     list.add(arr[2]);  
}  
abc1 = list.toArray(new String[0]);  

Here is the complete code -

import java.io.*;
import java.util.*;

public class DVDInfo {

    String title;
    String genre;
    String leadActor;

    DVDInfo() {
    }

    DVDInfo(String t, String g, String a) {
        title = t;
        genre = g;
        leadActor = a;
    }

    public String toString() {
        return title + "" + genre + "" + leadActor + "\n";
    }

    public static void main(String arg[]) throws IOException {
        String s;

        String[] abc1 = null;
        File abc = new File("movies.txt");
        abc.createNewFile();
        System.out.println(abc.createNewFile());
        FileReader fr = new FileReader(abc);
        BufferedReader br = new BufferedReader(fr);
        ArrayList<String> list = new ArrayList<String>();
        while ((s = br.readLine()) != null) {
            String[] arr = s.split("/");
            list.add(arr[0]);
            list.add(arr[1]);
            list.add(arr[2]);
        }
        abc1 = list.toArray(new String[0]);
        System.out.println(abc1[0]);
        new DVDInfo(abc1[0], abc1[1], abc1[2]);
        //System.out.println(abc1.length);

    }
}