Here is the code of java program to Read text File
Line by Line:
http://www.roseindia.net/java/beginners/java-read-file-line-by-line.shtml
http://www.roseindia.net/java/beginners/java-read-file-line-by-line.shtml
import java.io.*;
class FileRead
{
public static void main(String args[])
{
try{
// Open the file that is the first
// command line parameter
FileInputStream fstream = new FileInputStream("c:\\textfile.txt");
// Get the object of DataInputStream
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
//Read File Line By Line
while ((strLine = br.readLine()) != null) {
// Print the content on the console
System.out.println (strLine);
}
//Close the input stream
in.close();
}catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
}
}
}Other way of reading file data: import java.io.*; /** * How To Read File In Java with BufferedReader class * */ public class ReadUsingBufferedReader { public static void main(String[] args) { System.out.println("Reading File with BufferedReader class"); //Name of the file String fileName="test.text"; try{ //Create object of FileReader FileReader inputFile = new FileReader(fileName); //Instantiate the BufferedReader Class BufferedReader bufferReader = new BufferedReader(inputFile); //Variable to hold the one line data String line; // Read file line by line and print on the console while ((line = bufferReader.readLine()) != null) { System.out.println("File Line is: " + line); } //Close the buffer reader bufferReader.close(); }
catch(Exception e){ System.out.println("Error in reading file:" + e.getMessage()); } } }
Read a specific line:
import java.io.*; public class ReadSpecificLine { public static void main(String[] args) { String line = ""; int lineNo; try { FileReader fr = new FileReader("new.txt"); BufferedReader br = new BufferedReader(fr); for (lineNo = 1; lineNo < 10; lineNo++) { if (lineNo == 5) { line = br.readLine(); } else br.readLine(); } } catch (IOException e) { e.printStackTrace(); } System.out.println("Line: " + line); } }
Java read file in memory
import java.io.*; import java.nio.*; import java.nio.channels.*; public class ReadFileInMemory { public static void main(String[] args) throws Exception { File f = new File("C:/hello.txt"); long length = f.length(); MappedByteBuffer buffer = new FileInputStream(f).getChannel().map( FileChannel.MapMode.READ_ONLY, 0, length); int i = 0; while (i < length) { System.out.print((char) buffer.get(i++)); } System.out.println(); } }
Reading binary file into byte array in Java
import java.io.*;
public class ReadingBinaryFileIntoByteArray
{
public static void main(String[] args)
{
System.out.println("Reading binary file into byte array example");
try{
//Instantiate the file object
File file = new File("test.zip");
//Instantiate the input stread
InputStream insputStream = new FileInputStream(file);
long length = file.length();
byte[] bytes = new byte[(int) length];
insputStream.read(bytes);
insputStream.close();
String s = new String(bytes);
//Print the byte data into string format
System.out.println(s);
}
catch(Exception e){
System.out.println("Error is:" + e.getMessage());
}
}
}
Writing a file using Appending:
import java.io.*; class WriteToFileWithoutOverwriting { public static void main(String args[]) { try{ FileWriter fstream = new FileWriter("log.txt",true); BufferedWriter out = new BufferedWriter(fstream); out.write("Line Added on: " + new java.util.Date()+"\n"); out.close(); }catch (Exception e){ System.err.println("Error while writing to file: " + e.getMessage()); } } }
Copying Characters from One file to Another file (Copy file):
import java.io.*;
class CopyCharacters {
public static void main(String[] args) {
File inFile = new File("input.dat");
File outFile = new File("output.dat");
FileReader ins = null;
FileWriter outs = null;
try {
ins = new FileReader(inFile);
outs = new FileWriter(outFile);
int ch;
while((ch = ins.read()) != -1)
{
outs.write(ch);
}
}
catch(IOException e) {
System.out.println(e);
System.exit(-1);
}
finally {
ins.close();
outs.close();
}
}
}
Writing Bytes to a file:
import java.io.*;
class WriteBytes {
public static void main(String[] args) {
byte cities[] = {'D', 'E', 'L', 'H', 'I', '\n', 'M','A','D','R','S','\n'}
FileOutputStream outfile = null;
try {
outfile = new FileOutputStream("city.txt");
outfile.write(cities);
outfile.close();
}
catch(IOException e) {
System.out.println(e);
System.exit(-1);
}
}
}
Reading bytes from file:
import java.io.*;
class ReadBytes {
public static void main(String[] args) {
FileInputStream infile = null;
int b;
try {
infile = new FileInputStream(args[0]);
while ((b = infile.read())!= -1)
{
System.out.println((char)b);
}
infile.close();
}
catch( IOException e)
{
System.out.println(e);
}
}
}
