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Thread: FileInputStream

  1. #1
    pachufir is offline Member
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    Default FileInputStream

    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?

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    travishein's Avatar
    travishein is offline Senior Member
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    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,
    Java Code:
    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.
    }

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    hardwired's Avatar
    hardwired is offline Senior Member
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    trying to understand how the syntax of FileInputStream works...
    can someone show my some example code?

    Java 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());
            }        
        }
    }

  4. #4
    xcallmejudasx's Avatar
    xcallmejudasx is offline Senior Member
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    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
    }
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