Put byte array to JSON and vice versa

Question

Is it possible to put a byte[] (byte array) to JSON?

if so, how can I do that in java? then read that JSON and convert that field again to byte[]?

Answer 1

Here is a good example of base64 encoding byte arrays. It gets more complicated when you throw unicode characters in the mix to send things like PDF documents. After encoding a byte array the encoded string can be used as a JSON property value.

Apache commons offers good utilities:

 byte[] bytes = getByteArr();  String base64String = Base64.encodeBase64String(bytes);  byte[] backToBytes = Base64.decodeBase64(base64String); 

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding

Java server side example:

public String getUnsecureContentBase64(String url)         throws ClientProtocolException, IOException {              //getUnsecureContent will generate some byte[]     byte[] result = getUnsecureContent(url);              // use apache org.apache.commons.codec.binary.Base64             // if you're sending back as a http request result you may have to             // org.apache.commons.httpclient.util.URIUtil.encodeQuery     return Base64.encodeBase64String(result); } 

JavaScript decode:

//decode URL encoding if encoded before returning result var uriEncodedString = decodeURIComponent(response);  var byteArr = base64DecToArr(uriEncodedString);  //from mozilla function b64ToUint6 (nChr) {    return nChr > 64 && nChr < 91 ?       nChr - 65     : nChr > 96 && nChr < 123 ?       nChr - 71     : nChr > 47 && nChr < 58 ?       nChr + 4     : nChr === 43 ?       62     : nChr === 47 ?       63     :       0;  }  function base64DecToArr (sBase64, nBlocksSize) {    var     sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,     nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2, taBytes = new Uint8Array(nOutLen);    for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {     nMod4 = nInIdx & 3;     nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;     if (nMod4 === 3 || nInLen - nInIdx === 1) {       for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {         taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;       }       nUint24 = 0;      }   }    return taBytes; }