PushbackReader read() method in Java with Examples

Last Updated : 29 Apr, 2019

The read() method of PushbackReader Class in Java is used to read a single character from the stream. This method blocks the stream till:

It has taken some input from the stream.
Some IOException has occurred
It has reached the end of the stream while reading.

Syntax:

public int read()

Parameters: This method does not accepts any parameters

Return Value: This method returns an integer value which is the integer value read from the stream. It can range from 0 to 65535. Else it returns -1 if no character has been read.

Exception: This method throws IOException if some error occurs while input output.

Below methods illustrates the working of read() method:

Program 1:

// Java program to demonstrate 
// PushbackReader read() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
            // Initializing a StringReader 
            // and PushbackReader 
            String s = "GeeksForGeeks"; 
  
            StringReader stringReader 
                = new StringReader(s); 
            PushbackReader pushbackReader 
                = new PushbackReader(stringReader); 
  
            // Get the character 
            // to be read from the stream 
            int ch; 
  
            // Read the first 5 characters 
            // to this reader using read() method 
            // This will put the str in the stream 
            // till it is read by the reader 
            for (int i = 0; i < 5; i++) { 
                ch = pushbackReader.read(); 
                System.out.println("\nInteger value "
                                   + "of character read: "
                                   + ch); 
                System.out.println("Actual "
                                   + "character read: "
                                   + (char)ch); 
            } 
  
            // Close the stream using read() 
            pushbackReader.close(); 
            System.out.println("Stream Closed."); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
} 

Output:

Integer value of character read: 71
Actual character read: G

Integer value of character read: 101
Actual character read: e

Integer value of character read: 101
Actual character read: e

Integer value of character read: 107
Actual character read: k

Integer value of character read: 115
Actual character read: s
Stream Closed.

Program 2:

// Java program to demonstrate 
// PushbackReader read() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
            // Initializing a StringReader 
            // and PushbackReader 
            String s = "GFG"; 
  
            StringReader stringReader 
                = new StringReader(s); 
            PushbackReader pushbackReader 
                = new PushbackReader(stringReader); 
  
            // Get the character 
            // to be read from the stream 
            int ch; 
  
            // Read the first 2 characters 
            // to this reader using read() method 
            // This will put the str in the stream 
            // till it is read by the reader 
            for (int i = 0; i < 2; i++) { 
                ch = pushbackReader.read(); 
                System.out.println("\nInteger value "
                                   + "of character read: "
                                   + ch); 
                System.out.println("Actual "
                                   + "character read: "
                                   + (char)ch); 
            } 
  
            // Close the stream 
            pushbackReader.close(); 
            System.out.println("Stream Closed."); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
} 

Output:

Integer value of character read: 71
Actual character read: G

Integer value of character read: 70
Actual character read: F
Stream Closed.

Reference: https://docs.oracle.com/javase/9/docs/api/java/io/PushbackReader.html#read–

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PushbackReader read() method in Java with Examples

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