CODEWITHSUNDEEP
javaio
user1907700
user1907700

Reputation:

File I/O producing gibberish on output

I'm learning File I/O using Java.

Following are my codes from two different Java files. One is "File" with the main class, the other is "FileWrite."

I was able to implement string input and output. But the output textfile has gibberish in the beginning and I am not sure why.

[File.Java]

package file;

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

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

    try (BufferedReader br = new BufferedReader(new FileReader("B:\\fileIn.txt")))
            {
              String stCurrent;

              while ((stCurrent = br.readLine()) != null) {
                    System.out.println(stCurrent);
            }

            } catch (IOException e) {
                e.printStackTrace();
            } 
                    FileWrite fW = new FileWrite();
                    fW.serializeAddress("Boston", "Canada");
        }
}

[FileWrite.Java]

package file;

import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class FileWrite {

   public void serializeAddress(String city, String country) {
       try {
        FileOutputStream fout = new FileOutputStream("B:\\address.txt");
        ObjectOutputStream obOut = new ObjectOutputStream(fout);   
                obOut.writeUTF(city);
                obOut.writeUTF(country);
        obOut.close();
        System.out.println("Output Done");
       } catch(Exception ex) {
           ex.printStackTrace();
       }
   }
}

Now, on "obOut.writeUTF(city); obOut.writeUTF(country);" I separated out two string inputs. Is there a way to combine them into one? As in obOut.writeUTF(city, counry) instead of two. Or is this only achievable through making these into an object?

[Update] Imported a couple more and I tried 

PrintStream ps = new PrintStream(new FileWriter("B:\\addressPS.txt")); 
ps.println(city); 
ps.println(country); 
ps.close(); 
But with errors, any clue?

Upvotes: 1

Views: 2085

Answers (4)

bmargulies
bmargulies

Reputation: 100013

By definition, ObjectOutputStream produces 'gibberish'. It's not intended for human consumption, it is a format used to write out objects so that you can read them back. You're not supposed to be able to make sense of the results in a text editor. To make human-readable content, just use an OutputStreamWriter or even a PrintWriter. In short, your last example is correct, and if you get errors, please edit your question to tell us what the errors are.

Upvotes: 0

Sanchit
Sanchit

Reputation: 2260

The gibberish is because .writUTF() writes data in a modified UTF format which is mentioned in the javadocs.

An ObjectOutputStream is generally used to output OBJECTS but I suppose you can use it for strings as well. You can use the respective .readUTF() method in the ObjectInputStream class in order to read the data in your file back.

Also, you have tried to use the try-with-resources block which is new to Java SE7. You should NOT do it the way you have done so. You should do this instead:

try (FileReader fr = new FileReader("B:\\fileIn.txt"); BufferedReader br = new BufferedReader(fr);) {

} catch (FileNotFoundException e1) {
  e1.printStackTrace();
} catch (IOException e1) {
  e1.printStackTrace();
}

Splitting the FileReader and the BufferedReader will allow Java SE7 to close both the streams with ease. The way you have done it, only the BufferedReader stream will get closed after the try block finishes.

Upvotes: 0

Peter Lawrey
Peter Lawrey

Reputation: 533442

You are doing the right thing keeping them separate already. City and country are different fields.

A very common mistake is not making a distinction between binary and text files/socket streams. You are a mixing the two which will lead to confusion. I suggest you only sue text Writer/Reader or binary Input/OuptutStream unless you have a very clear idea of what you are doing.

In short if you what to write text use

PrintStream ps = new PrintStream(new FileWriter(textFileName));
ps.println(city);
ps.println(country);
ps.close();

Upvotes: 1

hmatar
hmatar

Reputation: 2419

writeUTF takes strings also, you don't have to create new object for city and county.

Cant you do obOut.writeUTF(city +" "+country); ?

Upvotes: 0

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