Java file io example

gistfile1.java

import java.io.BufferedReader;
import java.io.FileReader;

public class test {
    public static void main(String[] args) {

        // We must put bufferedIO type work in a try-catch block
        // because it could throw an exception.
        try {
            // Create a new buffered reader object,
            // remember that it takes in a file reader as an argument
            // to its constructor, so we just place it right here in
            // the parenthesis since we won't need to refer to the file
            // reader again. We are passing this source file as the file
            // to read.
            BufferedReader reader = new BufferedReader(new FileReader("test.java"));

            // Read the first line of input
            String temp = reader.readLine();

            // readline will return null if it is done reading the file.
            // so we check against it to know when to end our loop.
            while(temp != null) {
                // this is where we look at the individual characters
                // each line that we take in. Its a simple for loop.
                // Strings are basically an array of characters, so we
                // can look at their elements in a similar way.
                //
                // For this example, we will print out only the characters
                // that are curly braces
                for(int i = 0; i < temp.length(); i++) {
                    // Gets the character at position i in the
                    // current line.
                    char c = temp.charAt(i);

                    if(c == '}' || c == '{') {
                        System.out.println(c);
                    }
                }

                temp = reader.readLine();
            }

        } catch (Exception e) {
            System.out.println("Failed to open the file!");
        }

    }
}