2. Objective
On completion of this period, you would be able to
learn
• ByteStream classes
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3. Recap
In the last class, you have studied about the File class
• You have also studied about the various methods,
and properties of a File class
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4. Types of Stream Class
Java’s stream-based I/O is built upon four abstract
classes:
1. Input Stream
2. Output Stream
3. Reader
4. Writer
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5. Byte Streams
Byte Streams are two types
1. InputStream class
2. OutputStream class
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6. InputStream class
• Data is accessed as a sequence of bytes
• Its an abstract class that defines streaming byte
input
• The methods in the input stream are used to read
bytes from input stream
• All methods in this class will throw an I/O
Exception
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7. OutputStream class
• Is an abstract class that defines streaming byte
output
• The methods of it are used to send bytes to the
output stream
• All methods in this class return a void value and
throw an I/O Exception in the case of errors
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8. FileInputStream class
• Is a subclass of InputStream that you can use to read
bytes from a file
• Its has two constructors
• FileInputStream(String filePath)
• FileInputStream(File fileObj)
• When FileInputStream is created, it is also opened for
reading
• FileInputStream overrides six of the methods in the
abstract class InputStream
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9. // Program for FileInputStream
import java.io.*;
class FileInputStreamDemo {
public static void main(String args[]) throws Exception {
int size;
InputStream f =
new FileInputStream("FileInputStreamDemo.java");
System.out.println("Total Available Bytes: " +
(size = f.available()));
int n = size/40;
System.out.println("First " + n +
" bytes of the file one read() at a time");
for (int i=0; i < n; i++) {
System.out.print((char) f.read()); }
System.out.println("nStill Available: " + f.available());
System.out.println("Reading the next " + n +
" with one read(b[])");
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10. // Program for FileInputStream
byte b[] = new byte[n];
if (f.read(b) != n) {
System.err.println("couldn't read " + n + " bytes."); }
System.out.println(new String(b, 0, n));
System.out.println("nStill Available: " + (size = f.available()));
System.out.println("Skipping half of remaining bytes with skip()");
f.skip(size/2);
System.out.println("Still Available: " + f.available());
System.out.println("Reading " + n/2 + " into the end of array");
if (f.read(b, n/2, n/2) != n/2) {
System.err.println("couldn't read " + n/2 + " bytes."); }
System.out.println(new String(b, 0, b.length));
System.out.println("nStill Available: " + f.available());
f.close(); } }
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11. FileOutputStream class
• Is a subclass of OutputStream that you can use to
write bytes to a file
• Constructors are
• FileOutputStream(String filePath)
• FileOutputStream(File fileObj)
• FileOutputStream(String filePath, boolean append)
• FileOutputStream(File fileObj, boolean append)
• They can throw a FileNotFoundException or a
SecurityException
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12. Summary
• Byte Streams are two types: InputStream
and OutputStream
• In InputStream data is accessed as a
sequence of bytes
• FileInputStream and FilOuputStream are
the subclasses of ByteStream
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13. Quiz
1. All methods in InputStream class will throw an
IOException
A. True
B. False
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14. Quiz contd ..
2. Which method is used to read bytes from
InpuStream
A. readLine()
B. read()
C. write()
D. None
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15. Frequently Asked Questions
1. Write about Byte Stream classes
2. Write a java program which illustrates the use of
FileInputStream
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