FileInputStream

[pachufir]

Hi, I'm trying to understand how the syntax of FileInputStream works... I'm supposed to get input from the user of a name, then search a text document, which has a name on each line, to see whether that name is in the directory. How can i achieve this with FileInputStream.. can someone show my some example code?

[travishein]

Well, the FileInputStream itself is useful once we know a File object, or a String name of a file is a file that we want to read from, once it is created it works like a simple InputStream.

The File object has methods in it to test if the file exists, and is a valid file, or a directory.

for example,

String theFileName="aFile.txt";  // this was read in from the user.
File theFille = new File(theFileName);

if (theFile.exists() ) {
  // the user has entered a name that is a valid file.
  if (theFile.isDirectory() ) {
    // the file is a directory.
  }
  else {
    // the file is not a directory, possibly a file.
  }
}
else {
  // the user has entered a name that is not a file or directory that exists.
}

[hardwired]

trying to understand how the syntax of FileInputStream works...
can someone show my some example code?

import java.io.*;

public class Test {
    public static void main(String[] args) {
        String path = "Test.java";
        try {
            File file = new File(path);
            BufferedReader br = new BufferedReader(
                                new InputStreamReader(
                                new FileInputStream(file)));
            String line;
            while((line = br.readLine()) != null) {
                System.out.println(line);
            }
            br.close();
        } catch(IOException e) {
            System.out.println("read error: " + e.getMessage());
        }        
    }
}

[xcallmejudasx]

You could also use a scanner attached to a FileInputStream.

Scanner in = new Scanner(new FileInputStream(new File("myFile.txt")));

Then traversing through the file is done with a while loop

while(in.hasNext()){
//push the name that's returned using in.nextLine or in.next
}