Encoding as Base64 in Java

Question

I need to encode some data in the Base64 encoding in Java  How do I do that  What is the name of the class that provides a Base64 encoder     I tried to use the sun misc BASE64Encoder class  without success  I have the following line of Java 7 code   wr write new sun misc BASE64Encoder   encode buf      I m using Eclipse  Eclipse marks this line as an error  I imported the required libraries   import sun misc BASE64Encoder  import sun misc BASE64Decoder    But again  both of them are shown as errors  I found a similar post here   I used Apache Commons as the solution suggested by including   import org apache commons      and importing the JAR files downloaded from  http   commons apache org codec   But the problem still exists  Eclipse still shows the errors previously mentioned  What should I do

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I tried with the following code snippet  It worked well   -   com sun org apache xml internal security utils Base64 encode  The string to encode goes here

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GZIP   Base64 The length of the string in a Base64 format is greater then original  133  on average  So it makes sense to first compress it with GZIP  and then encode to Base64  It gives a reduction of up to 77  for strings greater than 200 characters and more  Example  public static void main String   args  throws IOException       byte   original   randomString 100  getBytes StandardCharsets UTF 8        byte   base64   encodeToBase64 original       byte   gzipToBase64   encodeToBase64 encodeToGZIP original         byte   fromBase64   decodeFromBase64 base64       byte   fromBase64Gzip   decodeFromGZIP decodeFromBase64 gzipToBase64            test     System out println  quot Original   quot    original length    quot  bytes  100  quot        System out println  quot Base64   quot    base64 length    quot  bytes   quot                 base64 length   100   original length     quot   quot        System out println  quot GZIP Base64   quot    gzipToBase64 length    quot  bytes   quot                 gzipToBase64 length   100   original length     quot   quot           Original  3700 bytes  100        Base64  4936 bytes  133        GZIP Base64  2868 bytes  77       System out println Arrays equals original  fromBase64       true     System out println Arrays equals original  fromBase64Gzip       true    public static byte   decodeFromBase64 byte   arr        return Base64 getDecoder   decode arr      public static byte   encodeToBase64 byte   arr        return Base64 getEncoder   encode arr      public static byte   decodeFromGZIP byte   arr  throws IOException       ByteArrayInputStream bais   new ByteArrayInputStream arr       GZIPInputStream gzip   new GZIPInputStream bais       return gzip readAllBytes       public static byte   encodeToGZIP byte   arr  throws IOException       ByteArrayOutputStream baos   new ByteArrayOutputStream        GZIPOutputStream gzip   new GZIPOutputStream baos       gzip write arr       gzip finish        return baos toByteArray       public static String randomString int count        StringBuilder str   new StringBuilder        for  int i   0  i  lt  count  i              str append  quot   quot   append UUID randomUUID   toString               return str toString

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You need to change the import of your class   import org apache commons codec binary Base64    And then change your class to use the Base64 class   Here s some example code   byte   encodedBytes   Base64 encodeBase64  Test  getBytes     System out println  encodedBytes     new String encodedBytes    byte   decodedBytes   Base64 decodeBase64 encodedBytes   System out println  decodedBytes     new String decodedBytes      Then read why you shouldn t use sun   packages     Update  2016-12-16   You can now use java util Base64 with Java nbsp 8  First  import it as you normally do   import java util Base64    Then use the Base64 static methods as follows   byte   encodedBytes   Base64 getEncoder   encode  Test  getBytes     System out println  encodedBytes     new String encodedBytes    byte   decodedBytes   Base64 getDecoder   decode encodedBytes   System out println  decodedBytes     new String decodedBytes      If you directly want to encode string and get the result as encoded string  you can use this   String encodeBytes   Base64 getEncoder   encodeToString  userName         password  getBytes         See Java documentation for Base64 for more

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In Java 7 I coded this method  import javax xml bind DatatypeConverter   public static String toBase64 String data        return DatatypeConverter printBase64Binary data getBytes

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In Java 8 it can be done as      Base64 getEncoder   encodeToString string getBytes StandardCharsets UTF 8    Here is a short  self-contained complete example   import java nio charset StandardCharsets  import java util Base64   public class Temp       public static void main String    args  throws Exception           final String s    old crow medicine show           final byte   authBytes   s getBytes StandardCharsets UTF 8           final String encoded   Base64 getEncoder   encodeToString authBytes           System out println s       gt      encoded             Output   old crow medicine show   gt  b2xkIGNyb3cgbWVkaWNpbmUgc2hvdw

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If you are using Spring Framework at least version 4 1  you can use the org springframework util Base64Utils class     byte   raw     1  2  3    String encoded   Base64Utils encodeToString raw   byte   decoded   Base64Utils decodeFromString encoded     It will delegate to Java 8 s Base64  Apache Commons Codec  or JAXB DatatypeConverter  depending on what is available

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Eclipse gives you an error warning because you are trying to use internal classes that are specific to a JDK vendor and not part of the public API  Jakarta Commons provides its own implementation of base64 codecs  which of course reside in a different package  Delete those imports and let Eclipse import the proper Commons classs for you

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Apache Commons has a nice implementation of Base64  You can do this as simply as      Encrypt data on your side using BASE64 byte   bytesEncoded   Base64 encodeBase64 str  getBytes     System out println  ecncoded value is     new String bytesEncoded        Decrypt data on other side  by processing encoded data byte   valueDecoded  Base64 decodeBase64 bytesEncoded    System out println  Decoded value is     new String valueDecoded      You can find more details about base64 encoding at Base64 encoding using Java and JavaScript

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If you are stuck to an earlier version of Java than 8 but already using AWS SDK for Java  you can use com amazonaws util Base64

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To convert this  you need an encoder  amp  decoder which you will get from Base64Coder - an open-source Base64 encoder decoder in Java  It is file Base64Coder java you will need   Now to access this class as per your requirement you will need the class below   import java io BufferedInputStream  import java io BufferedOutputStream  import java io BufferedReader  import java io BufferedWriter  import java io File  import java io FileInputStream  import java io FileOutputStream  import java io FileReader  import java io FileWriter  import java io InputStream  import java io IOException  import java io OutputStream   public class Base64        public static void main String args    throws IOException                         if  args length    2                   System out println                      Command line parameters  inputFileName outputFileName                   System exit 9                encodeFile args 0   args 1                        File sourceImage   new File  back3 png            File sourceImage64   new File  back3 txt            File destImage   new File  back4 png            encodeFile sourceImage  sourceImage64           decodeFile sourceImage64  destImage              private static void encodeFile File inputFile  File outputFile  throws IOException           BufferedInputStream in   null          BufferedWriter out   null          try               in   new BufferedInputStream new FileInputStream inputFile                out   new BufferedWriter new FileWriter outputFile                encodeStream in  out               out flush                      finally               if  in    null                  in close                if  out    null                  out close                         private static void encodeStream InputStream in  BufferedWriter out  throws IOException           int lineLength   72          byte   buf   new byte lineLength   4   3           while  true                int len   in read buf               if  len  lt   0                  break              out write Base64Coder encode buf  0  len                out newLine                         static String encodeArray byte   in  throws IOException           StringBuffer out   new StringBuffer            out append Base64Coder encode in  0  in length            return out toString               static byte   decodeArray String in  throws IOException           byte   buf   Base64Coder decodeLines in           return buf             private static void decodeFile File inputFile  File outputFile  throws IOException           BufferedReader in   null          BufferedOutputStream out   null          try               in   new BufferedReader new FileReader inputFile                out   new BufferedOutputStream new FileOutputStream outputFile                decodeStream in  out               out flush                      finally               if  in    null                  in close                if  out    null                  out close                         private static void decodeStream BufferedReader in  OutputStream out  throws IOException           while  true                String s   in readLine                if  s    null                  break              byte   buf   Base64Coder decodeLines s               out write buf                       In Android you can convert your bitmap to Base64 for Uploading to a server or web service   Bitmap bmImage     Data ByteArrayOutputStream baos   new ByteArrayOutputStream    bmImage compress Bitmap CompressFormat JPEG  100  baos   byte   imageData   baos toByteArray    String encodedImage   Base64 encodeArray imageData     This    encodedImage    is text representation of your image  You can use this for either uploading purpose or for diplaying directly into an HTML page as below  reference     lt img alt    src  data image png base64  lt  php echo  encodedImage    gt   width  100px    gt   lt img alt    src  data image png base64  9j 4AAQ           1f 9k   width  100px    gt    Documentation  http   dwij co in java-base64-image-encoder

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add this library into your app level dependancies implementation  org apache commons commons-collections4 4 4

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Here are my two cents    Java 8 does contain its own implementation of Base64  However  I found one slightly disturbing difference  To illustrate  I will provide a code example   My codec wrapper   public interface MyCodec     static String apacheDecode String encodedStr          return new String Base64 decodeBase64 encodedStr   Charset forName  UTF-8            static String apacheEncode String decodedStr          byte   decodedByteArr   decodedStr getBytes Charset forName  UTF-8         return Base64 encodeBase64String decodedByteArr          static String javaDecode String encodedStr          return new String java util Base64 getDecoder   decode encodedStr   Charset forName  UTF-8            static String javaEncode String decodedStr          byte   decodedByteArr   decodedStr getBytes Charset forName  UTF-8         return java util Base64 getEncoder   encodeToString decodedByteArr           Test Class   public class CodecDemo     public static void main String   args          String decodedText    Hello World         String encodedApacheText   MyCodec apacheEncode decodedText       String encodedJavaText   MyCodec javaEncode decodedText        System out println  Apache encoded text      MyCodec apacheEncode encodedApacheText        System out println  Java encoded text      MyCodec javaEncode encodedJavaText         System out println  Encoded results equal      encodedApacheText equals encodedJavaText         System out println  Apache decode Java      MyCodec apacheDecode encodedJavaText        System out println  Java decode Java      MyCodec javaDecode encodedJavaText         System out println  Apache decode Apache      MyCodec apacheDecode encodedApacheText        System out println  Java decode Apache      MyCodec javaDecode encodedApacheText            OUTPUT   Apache encoded text  U0dWc2JHOGdWMjl5YkdRaA0K  Java encoded text  U0dWc2JHOGdWMjl5YkdRaA   Encoded results equal  false Apache decode Java  Hello World  Java decode Java  Hello World  Apache decode Apache  Hello World  Exception in thread  main  java lang IllegalArgumentException  Illegal base64 character d     at java util Base64 Decoder decode0 Base64 java 714      at java util Base64 Decoder decode Base64 java 526      at java util Base64 Decoder decode Base64 java 549    Notice that the Apache encoded text contain additional line breaks  white spaces  at the end  Therefore  in order for my codec to yield the same result regardless of Base64 implementation  I had to call trim   on the Apache encoded text  In my case  I simply added the aforementioned method call to the my codec s apacheDecode   as follows   return Base64 encodeBase64String decodedByteArr  trim      Once this change was made  the results are what I expected to begin with   Apache encoded text  U0dWc2JHOGdWMjl5YkdRaA   Java encoded text  U0dWc2JHOGdWMjl5YkdRaA   Encoded results equal  true Apache decode Java  Hello World  Java decode Java  Hello World  Apache decode Apache  Hello World  Java decode Apache  Hello World    CONCLUSION  If you want to switch from Apache Base64 to Java  you must    Decode encoded text with your Apache decoder  Encode resulting  plain  text with Java    If you switch without following these steps  most likely you will run into problems  That is how I made this discovery

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Use Java 8 s never-too-late-to-join-in-the-fun class  java util Base64  new String Base64 getEncoder   encode bytes

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Simple example with Java 8   import java util Base64   String str    your string   String encodedStr   Base64 getEncoder   encodeToString str getBytes  utf-8

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On Android  use the static methods of the android util Base64 utility class  The referenced documentation says that the Base64 class was added in API level 8  Android nbsp 2 2  Froyo     import android util Base64   byte   encodedBytes   Base64 encode  Test  getBytes     Log d  tag    encodedBytes     new String encodedBytes     byte   decodedBytes   Base64 decode encodedBytes   Log d  tag    decodedBytes     new String decodedBytes

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You can also convert using Base64 encoding  To do this  you can use the javax xml bind DatatypeConverter printBase64Binary method   For example   byte   salt   new byte     50  111  8  53  86  35  -19  -47    System out println DatatypeConverter printBase64Binary salt

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Google Guava is another choice to encode and decode Base64 data   POM configuration    lt dependency gt      lt artifactId gt guava lt  artifactId gt      lt groupId gt com google guava lt  groupId gt      lt type gt jar lt  type gt      lt version gt 14 0 1 lt  version gt   lt  dependency gt    Sample code   String inputContent    Hello Vi t Nam   String base64String   BaseEncoding base64   encode inputContent getBytes  UTF-8         Decode System out println  Base64     base64String      SGVsbG8gVmnhu4d0IE5hbQ   byte   contentInBytes   BaseEncoding base64   decode base64String   System out println  Source content      new String contentInBytes   UTF-8        Hello Vi t Nam

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For Java 6-7  the best option is to borrow code from the Android repository  It has no dependencies   https   github com android platform frameworks base blob master core java android util Base64 java

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public String convertImageToBase64 String filePath        byte   fileContent   new byte 0       String base64encoded   null      try           fileContent   FileUtils readFileToByteArray new File filePath          catch  IOException e            log error  Error reading file       filePath             try           base64encoded   Base64 getEncoder   encodeToString fileContent         catch  Exception e            log error  Error encoding the image to base64   e             return base64encoded

[java] Encoding as Base64 in Java

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