im tasked with written two java programs. One program creates a file called 'userinput.txt', then writes everything the user inputs into the file. Once done a new file is created called 'Checksum.txt' and this file will write down the checksum for the 'userinput.txt' file after reading whats inside of it.
The 2nd program just reads the same 'userinput.txt' file and then generates a checksum and prints it onto the console (i also have to get the program to read the other checksum.txt file and display it int the console to compare the two but i havent gotten around to that yet).
Iv written the program for these two but my problem is they are both different checksum even though they are reading the same file. Im using Adler32 but CRC32 also gives me two different checksums (the one on console is always different to the one stored in checksum.txt) and im not sure whats causing it frankly :/
Here is the code that takes userinput and generates the checksum file:
package attemp2;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
import java.util.zip.Adler32;
import java.util.zip.CheckedInputStream;
public class main {
public static void main(String[] args) throws IOException {
System.out.println("All inputs will be recorded into a sigle file. Enter 'x' when done. A checksum File will aslo be created at the end");
FileWriter fw = new FileWriter("d:/input.txt", false); // clears previous entry in file.
while (true) {
Scanner input = new Scanner(System.in); //get user input
String ch = input.nextLine(); //stores user input
System.out.println(ch); //prints out what user just inputed
if (ch.equals("x")) { //stops running if 'x' is entered
break;
}
BufferedWriter writer = new BufferedWriter(new FileWriter("d:/input.txt", true));
writer.write(ch);
writer.newLine(); // Add new line
writer.close();
}
try {
FileReader reader = new FileReader("d:/input.txt");
BufferedReader br = new BufferedReader(reader);
// read line by line String line;
String read = "";
String line;
while ((line = br.readLine()) != null) {
read = read + line;
//prints out text in file currently
System.out.println(line);
}
//checksum.txt generation
byte buffer[] = read.getBytes();
ByteArrayInputStream bais = new ByteArrayInputStream(buffer);
CheckedInputStream cis = new CheckedInputStream(bais, new Adler32());
byte readBuffer[] = new byte[buffer.length];
cis.read(readBuffer);
FileOutputStream out = new FileOutputStream("d://checksum.txt");
BufferedWriter wrt = new BufferedWriter(new FileWriter("d:/checksum.txt", false));
wrt.write(Long.toString(cis.getChecksum().getValue()));
wrt.close();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
The code that reads the file and generates a checksum in console:
package check;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Scanner;
import java.util.zip.Adler32;
public class CheckSum {
private Adler32 checksum;
private String filepath;
InputStream inputStream;
public CheckSum(String filepath) throws FileNotFoundException{
this.filepath = filepath;
checksum = new Adler32();
inputStream = new FileInputStream(filepath);
}
public long generateChecksum() throws IOException{
int c;
while((c = inputStream.read())!=-1){
checksum.update(c);
}
return checksum.getValue();
}
public void read() throws IOException{
File file = new File(filepath);
BufferedReader br = new BufferedReader(new FileReader(file));
String st;
while ((st = br.readLine()) != null) {
System.out.println(st);
}
}
public static void main(String[] args) throws Exception{
Scanner scanner = new Scanner(System.in);
String filepath = "d:/input.txt";
CheckSum checksum = new CheckSum(filepath);
checksum.read();
System.out.println("For the file: "+filepath);
System.out.println("The checksum generated is: "+checksum.generateChecksum());
}
}
