Reader read(char[]) in Java

read(char[]): This method is available in the java.io.Reader class of Java.

Syntax:

int java.io.Reader.read(char[] cbuf) throws IOException

This method takes one argument. This method reads characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Parameters: One parameter is required for this method.

cbuf: Destination buffer.

Returns: The number of characters reads, or -1 if the end of the stream has been reached.

Throws:

1. IOException - If an I/O error occurs

Approach 1: When no exception

Java

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class Readerread2 {
    public static void main(String[] args) throws IOException {

        Reader reader = new StringReader("HELLO");

        char cbuf[] = { 'a', 'b', 'c', 'd', 'e' };

        System.out.println(reader.read(cbuf));
        reader.close();

    }
}

Output:

5


Approach 2: IOException

Java

package com.Reader;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class Readerread2 {
    public static void main(String[] args) throws IOException {

        Reader reader = new StringReader("HELLO");

        char cbuf[] = { 'a', 'b', 'c', 'd', 'e' };

        reader.close();
        System.out.println(reader.read(cbuf));

    }
}

Output:

Exception in thread "main" java.io.IOException: Stream closed at java.base/java.io.StringReader.ensureOpen(StringReader.java:56) at java.base/java.io.StringReader.read(StringReader.java:91) at java.base/java.io.Reader.read(Reader.java:229) at com.Reader.Readerread2.main(Readerread2.java:15)


Some other methods of Reader

close()This method closes the stream and releases any system resources associated with it.

mark(int)This method marks the present position in the stream.

markSupported()This method tells whether this stream supports the mark() operation. 

Reader.nullReader()This method returns a new Reader that reads no characters.

read()This method reads a single character.

read(char[])This method reads characters into an array.

read(CharBuffer)This method attempts to read characters into the specified character buffer.

read(char[], int, int)This method reads characters into a portion of an array.

ready()This method tells whether this stream is ready to be read.

reset()This method resets the stream.

skip(long)This method skips characters.

transferTo(Writer)This method reads all characters from this reader and writes the characters to the given writer in the order that they are read.

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