Merge pull request #6 from coderolls/blog/read-file-using-bufferreader

Add new blogpost on BufferReader

Author: gauravkukade

_posts/java-files-io/2021-01-03-read-file-using-bufferreader.md

@@ -0,0 +1,232 @@
+---
+layout: post
+title: "How To Read File Using BufferReader In Java?"
+author: gaurav
+image: assets/images/2021-01-03/read-file-using-bufferreader.png
+categories: [Java, Java File IO]
+description: "In this article we will see how to read a file using the `BufferReader` class in Java."
+
+---
+
+In this article we will see how to read a file using the `BufferReader `class in Java.
+
+`BufferReader` class reads text from a character-input stream. Because of buffering characters it provides an  efficient way to read characters, arrays, and lines.
+
+`BufferReader` provides two important  methods to read from the file. i.e `read()` and `readLine()`.
+
+You can specify the bufferSize in `BufferReader `constructer. But as [motioned in the docs](https://docs.oracle.com/javase/8/docs/api/java/io/BufferedReader.html), 
+>The default is large enough for most purposes.
+
+## BufferReader `read()` method
+
+`BufferReader` `read()` method reads a single character. IT returns the `int` representation of the char in range of 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached.
+
+We can cast `int` value returned by `read()` method to `char` to get the character value.
+
+I have given an example to read a file character by character using the `read()` method of the `BufferReader` class
+```java
+package com.coderolls;
+
+import java.io.*;
+
+/**
+ * A java program to read file character by character using the
+ * read() method of the BufferReader Class.
+ * 
+ * @author Gaurav Kukade at coderolls.com
+ */
+public class BufferReaderReadMethodExample {
+
+	public static void main(String[] args) {
+		
+        BufferedReader bufferedReader = null;
+		try {
+			bufferedReader = new BufferedReader(new FileReader("F:\\sample-text.txt"));
+			
+			int i;
+			//read each character using read() method and print it
+			while((i=bufferedReader.read())!=-1){  
+				System.out.print((char)i);  
+			}
+			 
+		}catch (IOException e) {
+			e.printStackTrace();
+		}finally {
+			try {
+				bufferedReader.close();
+			} catch (IOException e) {
+				e.printStackTrace();
+			}
+		}
+	}
+}
+```
+Output
+```
+Welcome to coderolls.com!
+```
+See [this example on GitHub](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-files-io/BufferReaderReadMethodExample.java).
+
+## BufferReader `readLine()` method
+As specified in the name, this method reads a line of text.
+
+A line is considered to be terminated by any one of a line feed ('\n') or  a carriage return ('\r').
+
+The `readLine()` method returns the content of a line as string except the line terminating character (i.e. `\n` or `\r`). Or it will return `null` if the end of the stream has been reached.
+
+I have given below an example to read file line by line using the `readLine()` method
+
+```java
+package com.coderolls;
+
+import java.io.*;
+
+/**
+ * A java program to read file line by line using the
+ * readLine() method of the BufferReader Class.
+ * 
+ * @author Gaurav Kukade at coderolls.com
+ *
+ */
+public class BufferReaderReadLineMethodExample {
+
+	public static void main(String[] args) {
+		
+        BufferedReader bufferedReader = null;
+		try {
+			bufferedReader = new BufferedReader(new FileReader("F:\\sample-text-two-lines.txt"));
+			
+			String line;
+			//read each line using readLine() method and print it
+			while((line = bufferedReader.readLine()) != null){  
+				System.out.println(line);  
+			}
+			 
+		}catch (IOException e) {
+			e.printStackTrace();
+		}finally {
+			try {
+				bufferedReader.close();
+			} catch (IOException e) {
+				e.printStackTrace();
+			}
+		}
+	}
+}
+```
+Output
+```java
+Welcome to coderolls.com!
+
+Visit coderolls to read more coding tutorials!
+```
+See [this example on GitHub](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-files-io/BufferReaderReadLineMethodExample.java).
+
+I have given below a combine example of the Java `BufferReader` `read()` and `readLine()` method below
+
+```java
+package com.coderolls;
+
+import java.io.*;
+
+public class BufferReaderExanple {
+
+	public static void main(String[] args) {
+		BufferedReader bufferedReader = null;
+		try {
+			bufferedReader = new BufferedReader(new FileReader("F:\\sample-text-two-lines.txt"));
+			
+		} catch (FileNotFoundException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		
+		readFileCharacterByCharacter(bufferedReader);
+		
+		readFileLineByLine(bufferedReader);
+		
+		try {
+			bufferedReader.close();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+	}
+	
+	/**
+	 * A method to read file content character by character using the BufferReader 
+	 * read() method
+	 * 
+	 * @param bufferedReader
+	 */
+	public static void readFileCharacterByCharacter(BufferedReader bufferedReader) {
+			try {
+				int i;
+				//read each character using read() method and print it
+				while((i=bufferedReader.read())!=-1){  
+					System.out.print((char)i);  
+				}
+			} catch (IOException e) {
+				e.printStackTrace();
+			}
+	}
+	
+	/**
+	 * A method to read file content line by line using the BufferReader 
+	 * readLine() method
+	 * 
+	 * @param bufferedReader
+	 */
+	public static void readFileLineByLine(BufferedReader bufferedReader) {
+		
+		try {
+			String line;
+			//read each line using readLine() method and print it
+			while((line = bufferedReader.readLine()) != null){  
+				System.out.println(line);  
+			} 
+		}catch (IOException e) {
+			e.printStackTrace();
+		}	
+	}
+}
+```
+
+See [this example on GitHub](https://github.com/coderolls/blogpost-coding-examples/blob/main/java-files-io/BufferReaderExanple.java).
+
+## `newBufferedReader()` method in Java 8 
+
+In Java 1.8 and above you can get a `BufferReader` instance using the `newBufferedReader()` method of the `java.nio.file.Files` class.
+
+## Conclusion
+
+You can read file character by character using the `read()` method of the `BufferReader`Class.
+
+`read()` method returns an integer value, you have to cast it to `char` to get character value.
+
+Also, you can read file line by line using the `readLine()` method of the `BufferReader`Class
+
+`readLine()` methods returns the line content as string, except the line terminating character
+
+You can visit my [YouTube channel 'coderolls'](https://www.youtube.com/channel/UCl31HHUdQbSHOQfc9L-wo3w?view_as=subscriber?sub_confirmation=1) to find more video tutorials.
+
+--------------
+
+You can support me by [giving a cup of Coffee ☕](https://www.paypal.me/GauravKukade)
+
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