I'm currently working on a lab in my cpe class and we have to create a simple program that scans in strings from a .txt file and prints them to a different .txt file. So far I have the basic program drawn out but my exception keeps getting throw though I have all the necessary files. Can anyone help me debug?
import java.io.*;
import java.util.*;
public class FileIO {
public static void main(String args[]) {
try {
File input = new File("input");
File output = new File("output");
Scanner sc = new Scanner(input);
PrintWriter printer = new PrintWriter(output);
while(sc.hasNextLine()) {
String s = sc.nextLine();
printer.write(s);
}
}
catch(FileNotFoundException e) {
System.err.println("File not found. Please scan in new file.");
}
}
}
You need to figure out where it looks for the "input"
file. When you just specify "input"
it looks for the file in the current working directory . When working with an IDE, this directory may not be what you think it is.
Try the following:
System.out.println(new File("input").getAbsolutePath());
to see where it looks for the file.
May be you are just forget the flush()
try {
File input = new File("input");
File output = new File("output");
Scanner sc = new Scanner(input);
PrintWriter printer = new PrintWriter(output);
while (sc.hasNextLine()) {
String s = sc.nextLine();
printer.write(s);
}
**printer.flush();**
}
catch (FileNotFoundException e) {
System.err.println("File not found. Please scan in new file.");
}
When accessing files with Java I/O, you must include the file's filetype extension (if one exists).
File input = new File("input.txt");
File output = new File("output.txt");
We can do this by reading the file using FileInputStream object and write into another file using FileOutputStream object.
Here is the sample code
package java_io_examples;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Vector;
public class Filetest {
public static void main(String[] args) {
try {
FileInputStream fin = new FileInputStream("D:\\testout.txt");
int i = 0;
String s = "";
while((i=fin.read())!=-1) {
s = s + String.valueOf((char)i);
}
FileOutputStream fout = new
FileOutputStream("D:\\newtestout1.txt");
byte[] b = s.getBytes();
fout.write(b);
fout.close();
System.out.println("Done reading and writing!!");
} catch(Exception e){
System.out.println(e);
}
}
}
public void readwrite() throws IOException
{
// Reading data from file
File f1=new File("D:/read.txt");
FileReader fr=new FileReader(f1);
BufferedReader br=new BufferedReader(fr);
String s = br.readLine();
// Writing data
File f2=new File("D:/write.txt");
FileWriter fw=new FileWriter(f2);
BufferedWriter bw=new BufferedWriter(fw);
while(s!=null)
{
bw.write(s);
bw.newLine();
System.out.println(s);
s=br.readLine();
}
bw.flush();
bw.close();
}
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