Introduction

In this blog we will know how to read and write to a file in java.
  1. /*File reading by using FileInputStream/FileReader*/
  2. import java.io.*;
  3. import java.util.*;
  4. public class readFile
  5. {
  6. public static void main(String arg[])throws Exception
  7. {
  8. System.out.print("Provide name of file to read ");
  9. Scanner sc=new Scanner(System.in);
  10. String s=sc.next();
  11. //FileInputStream fis=new FileInputStream(s);
  12. FileReader fis=new FileReader(s);
  13. int x;
  14. while((x=fis.read())!=-1)
  15. System.out.print((char)x);
  16. }
  17. }
compile
javac readFile.java
java readFile
  1. /*File writing by using FileOutputStream/FileWriter*/
  2. import java.io.*;
  3. import java.util.*;
  4. public class writeFile
  5. {
  6. public static void main(String arg[])throws Exception
  7. {
  8. Scanner sc=new Scanner(System.in);
  9. System.out.print("Provide file name:");
  10. String fname=sc.next();
  11. System.out.print("Provide data to be written:");
  12. String data=sc.next();
  13. //To use FileWriter
  14. FileWriter fw=new FileWriter(fname,true);
  15. fw.write(data);
  16. fw.close();
  17. }
  18. }
compile
javac writeFile.java
java writeFile