In the previous article, we discussed about two basic file
handling functions in Java including searching for an existing created file in
the system and creating a file using java’s inbuilt function.
In this article we will cover up the other two file handling
operations which includes reading from a file and writing to a file using java’s
own methods. In this program we create a file by specifying a file name, open
it at the same time and add records to it as per custom format. After writing
to the file, it is good practice to close it.
import java.io.*;
import java.lang.*;
import java.util.*;
public class FileHandlingTrial {
private Formatter file;
public void openFile (){ //creating &
opening a file
try{
file= new Formatter("New Text
Document.txt"); //will be created in default workspace folder else specify a
path
}
catch(Exception e){
System.out.println("Illegal file
operation");
}
}
public void addRecords(){// writes to the
created file
file.format("%s %s
%s",
"99", "MCA", "IP
University");
}
public void closeFile(){ //good practice to
close the file after use
file.close();
}
}
class FileHandlingTrial1 {
public static void main(String[] args){
FileHandlingTrial asp = new FileHandlingTrial();
asp.openFile();
asp.addRecords();
asp.closeFile();
}
}
In this last program of file handling we will read the
content added by the user.
Here also we create three methods in which first opens
the file, second reads the content of the file and third one finally closes the
file after reading the contents.
import java.io.*;
import java.util.*;
public class FileHandlingTrial {
private Scanner file;
public void openFile(){ // to open the file
try{
file = new Scanner(new File("new.txt"));
}
catch(Exception e){
System.out.println("File not
found");
}
}
public void readFile(){ // to read data
from the file
while(file.hasNext()){
String
a=file.next();
String
b=file.next();
String
c=file.next();
String
d=file.next();
System.out.printf("%s %s %s
%s\n",
a, b, c, d);
}
}
public void closeFile(){
file.close();
}
}
class FileHandlingTrial1 {
public static void main(String[] args){
FileHandlingTrial asp = new FileHandlingTrial();
asp.openFile();
asp.readFile();
asp.closeFile();
}
}
Screenshot // click to open a higher resolution version
