I/O Java
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
public class Concat {
public boolean accept(File file) {
//if the file extension is .txt or .java return true, else false
if (file.getName().endsWith(".txt")||file.getName().endsWith(".java")) {
return true;
}
return false;
}
public void copy(PrintWriter pw, String inputFile)
{
File f = new File(inputFile);
if(accept(f)==true){
try {
Scanner scan = new Scanner(f);
pw= new PrintWriter(new FileOutputStream("Stuff.txt"));
while (scan.hasNextLine())
{
String s = scan.nextLine();
pw.println(s);
}
scan.close();
} catch (FileNotFoundException e) {
System.out.println(" Error: "+e + " "+ inputFile);
}
}else{
System.out.println("File name must be a TEXT Or JAVA type");
}
}
// The routine will throw a RuntimeException if the inputFile name does
// note end with .java or .txt
// This routine will also throw a RuntimeException if any problem occurs in
// opening the inputFile
// The copy routine copies the contents of the inputFile into the PrintWriter
public void concat(String outFile, String[] inputFiles)
{
try {
PrintWriter writer = new PrintWriter(outFile);
for(int i=0;i<inputFiles.length;i++){
String source=inputFiles[i];
copy(writer,source);
}
} catch (IOException e)
{
System.err.println(e);
System.exit(1);
}
// Fill in details.
// The routine will call copy to do a copy of a single file
// This routine will also create an open PrintWriter for the outFile
// If any problem occurs, a RuntimeException should be thrown with
// appropriate error information
}
public static void main(String[] args) {
if (args == null || args.length < 2)
{
System.out.println("Concat needs at least 2 filenames");
return;
}
try
{
String[] inputFiles = new String[args.length-1];
for (int i=0; i < inputFiles.length; i++)
inputFiles[i] = args[i+1];
Concat c = new Concat();
c.concat(args[0], inputFiles);
}
catch (RuntimeException e)
{
// Possible errors:
// An input file that doesn't end with .java or .txt
// An input file that doesn't open properly.
// Trouble creating the output file
System.out.println(" Error in Concat:"+e);
}
}
}
View Answers
September 12, 2012 at 1:45 AM
I am not really sure why This program is not running properly? Any ideas? Thanks in advance.
September 13, 2012 at 1:02 PM
Here is an example of concatenating text files.
import java.io.*;
import java.util.*;
public class Concat {
static public void main(String arg[]) throws java.io.IOException {
PrintWriter pw = new PrintWriter(new FileOutputStream("c:/concat.txt"));
Scanner input=new Scanner(System.in);
System.out.print("How many files you want to concat?:");
int no=input.nextInt();
String f[]=new String[no];
System.out.println("Enter filenames: ");
for(int i=0;i<f.length;i++){
String filename=input.next();
int mid= filename.lastIndexOf(".");
String ext=filename.substring(mid+1,filename.length());
if(ext.equals("txt")){
f[i]=filename;
System.out.println("Processing " + f[i] + "... ");
BufferedReader br = new BufferedReader(new FileReader(f[i]));
String line = br.readLine();
while (line != null) {
pw.println(line);
line = br.readLine();
}
br.close();
}
else{
System.out.print("Only txt files should be concated.Re-enter file name: ");
}
}
pw.close();
System.out.println("All files have been concatenated into concat.txt");
}
}
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