Java Scanner class reading strings

Question

I've created a scanner class to read through the text file and get the value what I'm after. Let's assume that I have a text file contains.

List of people: length 3

1 : Fnjiei : ID 7868860 : Age 18

2 : Oipuiieerb : ID 334134 : Age 39

3 : Enekaree : ID 6106274 : Age 31

I'm trying to get a name and id number and age, but everytime I try to run my code it gives me an exception. Here's my code. Any suggestion from java gurus?:) It was able to read one single line....... but no more than a single line of text.

    public void readFile(String fileName)throws IOException{
    Scanner input = null;
    input = new Scanner(new BufferedReader(new FileReader(fileName)));
    try {
        while (input.hasNextLine()){
            int howMany = 3;
            System.out.println(howMany);
            String userInput = input.nextLine();
            String name = "";
            String idS = "";    
            String ageS = "";
            int id;
            int age;
            int count=0; 
            for (int j = 0; j <= howMany; j++){
                for (int i=0; i < userInput.length(); i++){
                    if(count < 2){ // for name
                        if(Character.isLetter(userInput.charAt(i))){
                            name+=userInput.charAt(i); // store the name
                        }else if(userInput.charAt(i)==':'){
                            count++;
                            i++;
                        }
                    }else if(count == 2){ // for id
                        if(Character.isDigit(userInput.charAt(i))){
                            idS+=userInput.charAt(i); // store the id
                        }
                        else if(userInput.charAt(i)==':'){
                            count++;
                            i++;
                        }
                    }else if(count == 3){ // for age
                        if(Character.isDigit(userInput.charAt(i))){
                            ageS+=userInput.charAt(i); // store the age
                        }
                    }
                    id = Integer.parseInt(idS); // convert id to integer
                    age = Integer.parseInt(ageS); // convert age to integer
                    Fighters newFighters = new Fighters(id, name, age);
                    fighterList.add(newFighters);
                }
                userInput = input.nextLine();
            }
        }
    }finally{
        if (input != null){
            input.close();
        }
    }
}

My appology if my mere code begs to be changed.

Edited It gives me a number format exception!!! I dont know how many empty space would be there between these values.

Answer 1

Here's a solution that uses only Scanner API, the important one being findInLine . It can handle minor syntactic variations in the input format, and yet it's very readable, requiring no need for fancy regex or magic array indices.

    String text =
        "List  of @#%^$ people : length  3  !@%# \n" + 
        "1 :   Fnjiei   : ID 7868860 ::: Age 18\n" +
        "   2: Oipuiieerb : ID 334134 : Age 39 (old, lol!) \r\n" + 
        " 3 : Enekaree : ID 6106274 => Age 31\n";
    Scanner sc = new Scanner(text);

    sc.findInLine("length");
    final int N = sc.nextInt();

    for (int i = 0; i < N; i++) {
        sc.nextLine();
        sc.findInLine(":");
        String name = sc.next();
        sc.findInLine("ID");
        long id = sc.nextLong();
        sc.findInLine("Age");
        int age = sc.nextInt();
        System.out.printf("[%s] %s (%s)%n", id, name, age);
    }

This prints:

[7868860] Fnjiei (18)
[334134] Oipuiieerb (39)
[6106274] Enekaree (31)

API links

• Scanner.findInLine(Pattern pattern)
  • Attempts to find the next occurrence of the specified pattern ignoring delimiters.
  • Use this Pattern.compile overload if performance is an issue

Answer 2

This seems to be shorter:

public void readFile(String fileName)throws IOException
    {
        Scanner input = null;
        input = new Scanner(new BufferedReader(new FileReader(fileName)));
        String userInput;
        try
        {
            while (input.hasNextLine())
            {
                userInput = input.nextLine().trim();
                if (userInput.length() > 0)
                {
                    String[] userInfo = userInput.split(":");
                    int count = Integer.parseInt(userInfo[0].trim());
                    String name = userInfo[1].trim();
                    int id = Integer.parseInt(userInfo[2].trim().split("\\s+")[1].trim());
                    int age = Integer.parseInt(userInfo[3].trim().split("\\s+")[1].trim());

                    System.out.println("Count: " + count + " Name: " + name + " ID:" + id + " Age:" + age);
                }
                Fighters newFighters = new Fighters(id, name, age);
                fighterList.add(newFighters);
            }


        }
        finally
        {
            if (input != null)
            {
                input.close();
            }
        }
    }

For the input you have us, it prints this:

Count: 1 Name: Fnjiei ID:7868860 Age:18

Count: 2 Name: Oipuiieerb ID:334134 Age:39

Count: 3 Name: Enekaree ID:6106274 Age:31

More information about the split method can be found here . I basically first split the line by using the : as delimiter, then, I split again using the \\\\s+ , which basically splits a string and return an array containing the words that were separated by white spaces.

Answer 3

Scanner input = null;
input = new Scanner(new BufferedReader(new FileReader("filename")));

    try{
       while(input.hasNextLine()){
         String userInput = input.nextLine();
         String[] data = userInput.split(":");
         System.out.println("Name: "+data[1]+" ID:"+data[2].split("\\s+")[2]+
            "  Age:"+data[3].split("\\s+")[2]);

            }
        }finally{

            if(input != null) 
             input.close();
     }

Above snippet shows the basic idea.Also please keep in mind that this might not be the optimal solution.