Java base64 to inputstream java

A Base64.InputStream will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.

Constructor Summary
Base64.InputStream (java.io.InputStream in) Constructs a Base64.InputStream in DECODE mode.
Base64.InputStream (java.io.InputStream in, int options) Constructs a Base64.InputStream in either ENCODE or DECODE mode.

Method Summary
int	read () Reads enough of the input stream to convert to/from Base64 and returns the next byte.
int	read (byte[] dest, int off, int len) Calls read() repeatedly until the end of stream is reached or len bytes are read.

Methods inherited from class java.io.FilterInputStream
available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Base64.InputStream

public Base64.InputStream(java.io.InputStream in)

Parameters: in — the java.io.InputStream from which to read data. Since: 1.3

Base64.InputStream

public Base64.InputStream(java.io.InputStream in, int options)

ENCODE or DECODE: Encode or Decode as data is read. DONT_BREAK_LINES: don't break lines affineTransform 76 characters (only meaningful when encoding) Note: Technically, this makes your encoding non-compliant.

Example: new Base64.InputStream( in, Base64.DECODE )

Parameters: in — the java.io.InputStream from which to read data. options — Specified options Since: 2.0 See Also: Base64.ENCODE , Base64.DECODE , Base64.DONT_BREAK_LINES

Method Detail

read

public int read() throws java.io.IOException

Overrides: read in class java.io.FilterInputStream Returns: next byte Throws: java.io.IOException Since: 1.3

read

public int read(byte[] dest, int off, int len) throws java.io.IOException

Calls read() repeatedly until the end of stream is reached or len bytes are read. Returns number of bytes read into array or -1 if end of stream is encountered.

Overrides: read in class java.io.FilterInputStream Parameters: dest — array to hold values off — offset for array len — max number of bytes to read into array Returns: bytes read into array or -1 if end of stream is encountered. Throws: java.io.IOException Since: 1.3

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Java base64 to inputstream java

Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Method Summary

Methods inherited from class org.apache.commons.codec.binary.BaseNCodecInputStream

Methods inherited from class java.io.FilterInputStream

Methods inherited from class java.lang.Object

Constructor Detail

Base64InputStream

Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.

Base64InputStream

public Base64InputStream(InputStream inputStream, boolean doEncode)

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Base64InputStream

public Base64InputStream(InputStream inputStream, boolean doEncode, int lineLength, byte[] lineSeparator)

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

Base64InputStream

public Base64InputStream(InputStream inputStream, boolean doEncode, int lineLength, byte[] lineSeparator, CodecPolicy decodingPolicy)

Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original provided InputStream.

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Base64 Stream Examples in Java

The following examples use Apache’s Commons Codec library which is available on Maven Central by using the following dependency in your pom.xml file.

dependency> groupId>commons-codecgroupId> artifactId>commons-codecartifactId> version>1.15version> dependency>

Reading and Writing a Base64 String Example

The following code will allow you to read or decode a Base64 encoded String in Java. This is useful for data that is short or limited in length. Note that there are two steps involved in this process:

First, we decode the data back into a binary format using the Base64 class’s decodeBase64 helper method. If your data was only binary data to begin with, you can simply use the data as it returns.
Second, since my original data was UTF-8 encoded text I convert that binary data back into a String using Apache’s StringUtils class.

import org.apache.commons.codec.binary.Base64; import org.apache.commons.codec.binary.StringUtils; public class Base64Example  public static void main(String[] args)  // An example of a Base64 encoded String String base64 = "SGVsbG8gV29ybGQhIFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBCYXNlNjQgZW5jb2RlZCBkYXRhLg= token punctuation">; // Decode the Base64 String and get a byte array containing the data byte[] bytes = Base64.decodeBase64(base64); // Convert the byte array to a UTF-8 String String utf8 = StringUtils.newStringUtf8(bytes); System.out.println(utf8); > >

Reading Base64 Data from a File Stream Example

The following code uses Apache’s Base64InputStream to read base64 data and decode it in a conventional stream type of format.

This is useful for decoding large amounts of Base64 encoded data or used within processes where data is consumed using a stream. You can simply wrap a FileInputStream with the Base64InputStream so base64 data is automatically decoded as you consume bytes from an InputStream.

// An example of a Base64 encoded String String base64 = "SGVsbG8gV29ybGQhIFRoaXMgaXMgYW4gZXhhbXBsZSBvZiBCYXNlNjQgZW5jb2RlZCBkYXRhLg= token punctuation">; // Write our Base64 String into a text file try (FileWriter fileWriter = new FileWriter("base64.txt"))  fileWriter.write(base64); > // Use Apache's Base64InputStream to read the data in from our file try (Scanner scanner = new Scanner(new Base64InputStream(new FileInputStream("base64.txt"))))  while (scanner.hasNextLine())  // Print the line to the console System.out.println(scanner.nextLine()); > >

Reading Base64 data from a Socket InputStream

The following code can be used in tandem with the next section’s code on using a ServerSocket to write data. Simply run this codebase after starting the following server socket code.

We can even wrap a Java Socket’s InputStream with a Base64InputStream so that all of the data is sent over the network encoded in base64 format.

This is sometimes helpful when writing binary data to a socket that also sends zero or null byte terminated-strings. This way the low bytes of the binary data do not interfere with the newline or zero byte characters of the stream.
Additionally, this can be useful when attempting to send encrypted data over a socket in the same fashion, as what was originally a String is changed to bytes ranging from 0-255.

import org.apache.commons.codec.binary.Base64InputStream; import java.io.IOException; import java.net.InetSocketAddress; import java.net.Socket; import java.util.Scanner; public class SocketReadBase64  public static void main(String[] args) throws IOException  Socket socket = new Socket(); // Connect to our server (localhost, port 5555) socket.connect(new InetSocketAddress("0.0.0.0", 5555)); // Wrap our Socket's InputStream with a Base64 InputStream try (Scanner scanner = new Scanner(new Base64InputStream(socket.getInputStream())))  while (scanner.hasNextLine())  // Print the line to the console System.out.println(scanner.nextLine()); > > > >

Writing Base64 data using a ServerSocket OutputStream

The following code reads a Base64 Encoded file on the disk (decoding it in the process) and then re-encodes the file into base64, writing those bytes to the first socket connection the ServerSocket receives.

import org.apache.commons.codec.binary.Base64InputStream; import org.apache.commons.codec.binary.Base64OutputStream; import java.io.FileInputStream; import java.io.IOException; import java.net.ServerSocket; import java.net.Socket; public class ServerSocketBase64  public static void main(String[] args) throws IOException  ServerSocket server = new ServerSocket(5555); Socket socket = server.accept(); // Wrap the socket channel's OutputStream with a Base64OutputStream so data can be written back out in Base64 try (Base64OutputStream base64OutputStream = new Base64OutputStream(socket.getOutputStream()))  // Read and decode our base64 data file with a Base64InputStream wrapping a FileInputStream try (Base64InputStream base64InputStream = new Base64InputStream(new FileInputStream("base64.txt")))  // Write a single byte at a time to our outputstream. This can be further improved by using a buffer for (int data = base64InputStream.read(); data != -1; data = base64InputStream.read())  base64OutputStream.write(data); > > > > >

Encode a file into base64 in Java

For comparison, here is how to encode a file into base64 without using streams. Note this will not scale well as it can consume large amounts of memory if you are converting a large file.

import java.io.File; import java.io.FileInputStream; import java.io.FileWriter; import java.io.IOException; import java.util.Base64; public class Base64Example  public static void main(String[] args) throws IOException  // Read the file into a byte array using try with resources File file = new File("path/to/file.txt"); byte[] data = new byte[(int) file.length()]; try (FileInputStream fis = new FileInputStream(file))  fis.read(data); > // Encode the byte array into base64 String encoded = Base64.getEncoder().encodeToString(data); // Write the encoded base64 string to a file File outputFile = new File("path/to/output.txt"); try (FileWriter fw = new FileWriter(outputFile))  fw.write(encoded); > > >

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