Java I/O 1

[oconv]

Hi , I am very very very confused with Java I/O , there are a million classes to use for I/O , from what I could gather , the best for Byte Streams will be:

to wrap FileInputStream in the
DataInputStream for reading
& to wrap FileOutputStream in
DataOutputStream

and for Character Streams
to wrap FileReader in BufferedReader
for reading
& to wrap FileWriter in PrintWriter
for writing

am I on the right track ?? - Please don't be to hard on me I am trying to learn this ;-)

Christiaan

 

[VanDavid]

Yes, you got it.

As what you stated, java works like this:
1,
For input:
FileInputStream fis = new FileInputStream(f1)
or
FileInputStream fis = new
FileInputStream(¡°C:\\dir\\myfile¡±);
Attempts to open the file; may throw a FileNotFoundException

DataInputStream dis = new DataInputStream(fis); // then add functionality to your program
int i = dis.readInt(); //works if binary, just an example

For output:
FileOutputStream fos = new
FileOutputStream(¡°C:\\dir\\file2¡±);


2,
Text files (strings)
For input:
File f1 = new File(¡°C:\\dir\\myfile.txt¡±);
FileReader fr = new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
String s = br.readLine();

For output:
File f2 = new File(¡°C:\\dir\\newfile.txt¡±);
FileWriter fw = new FileWriter(f2);
PrintWriter pw = new PrintWriter(fw);
pw.println(s);


Hope this can help

 

[oconv]

Excellent !!! Thanx a 1000000

now -

you will loop through your file until you get the EOF marker
does the statment - String s = br.readLine();
read line for line

so if your file looks like (where <crlf> = characters for charage return line feed):

this is line 1<crlf>
this is line 2<crlf>
this is line 3<crlf>

s = &quot;this is line 1&quot;
and then s = &quot;this is line 1&quot; and so on and on

 

[VanDavid]

Correct! But if you would like to read elements(String) within a line, you need the StringTokenizer. It can break the line into elements (Strings), check the API for details.
Good luck!

David