Java Byte Array to String

By Arvind Rai, December 15, 2022

On this page, we will learn to convert byte[] to String in our Java application. We can convert byte[] to String using String constructors. The String provides constructors for this purpose using bytes, offset, length and charset parameters.

1. Using bytes

Find the String constructor from Java doc.

public String(byte[] bytes)

It constructs a new String by decoding the specified bytes array using default charset of the platform.
Example :

byte[] bytes =  "Hello World!".getBytes();
String s = new String(bytes);
System.out.println(s);

Output

Hello World!

2. Using bytes, offset and length

Find the String constructor using bytes, offset and length.

public String(byte[] bytes, int offset, int length)

Constructs new String using following parameters.
bytes : The bytes to be decoded into characters.
offset : The index of the first byte to decode.
length : The number of bytes to decode.

Example :

byte[] bytes =  "My name is Neo.".getBytes();
String s = new String(bytes, 3, 12);
System.out.println(s);

Output

name is Neo.

3. Using bytes, offset, length and charsetName

Find the String constructor using bytes, offset, length and charsetName.

public String(byte[] bytes, int offset, int length, String charsetName)

Constructs new String.
charsetName : The name of a supported charset.
Throws
The method can throw UnsupportedEncodingException and IndexOutOfBoundsException.

Example :
We can use standard charsets such as US-ASCII, ISO-8859-1, UTF-8, UTF-16BE, UTF-16LE and UTF-16 .
Example :

String s = new String(bytes, 3, 12, "US-ASCII");

4. Using bytes, offset, length and charset

Find the String constructor using bytes, offset, length and charset.

public String(byte[] bytes, int offset, int length, Charset charset)

Constructs new String.
charset : The Charset to be used to decode the byte.
Example

String s = new String(bytes, 3, 12, StandardCharsets.US_ASCII);

5. Using bytes and charsetName

Find the String constructor using bytes and charsetName.

String(byte[] bytes, String charsetName)

Constructs new String.
Example :

String s = new String(bytes, "UTF-8");

6. Using bytes and charset

Find the String constructor using bytes and charset.

String(byte[] bytes, Charset charset)

Constructs new String.
Example :

String s = new String(bytes, StandardCharsets.UTF_8);

Reference

Class String

POSTED BY

ARVIND RAI

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