How to convert JSON to Base64 string in Java?

Question

I have a JsonObject (Gson) I want to encrypt this json with Aes256 before I send it to the server, so I have to convert it to Base64 first

JsonObject jsonObject = new JsonObject();
jsonObject.addProperty("command", "abc");


String body = Base64.encodeToString(jsonObject.toString().getBytes("UTF-8"), Base64.NO_WRAP);

String finalBody = aesKeyIv.encrypt(body);

However it sends malformed json because it cannot convert properly.

EDIT: This is for Android

My encrypt method:

 public String encrypt(String value) throws Exception {
        byte[] encrypted = cipherEnc.doFinal(value.getBytes());
        return Base64.encodeToString(encrypted, Base64.NO_WRAP);
    }

Answer 1

You can import the library:

import org.apache.commons.codec.binary.Base64;

Then you can use following code for encoding into Base64:

public byte[] encodeBase64(String encodeMe){
byte[] encodedBytes = Base64.encodeBase64(encodeMe.getBytes());
return encodedBytes ;
} 

and for decoding you can use

public String decodeBase64(byte[] encodedBytes){
byte[] decodedBytes = Base64.decodeBase64(encodedBytes);
return new String(decodedBytes)
}

---

And if you are using Java 8 then you have Base64 class directly available into package:

import java.util.Base64; 

And your code for encoding into Base64 will change to :

public String encodeBase64(byte [] encodeMe){
    byte[] encodedBytes = Base64.getEncoder().encode(encodeMe);
    return new String(encodedBytes) ;
    } 

and similarly your new decoding will change as

public byte[]decodeBase64(String encodedData){
    byte[] decodedBytes = Base64.getDecoder().decode(encodedData.getBytes());
    return decodedBytes ;
    }

Answer 2

您可以使用Bouncy Castle和Apache Commons api转换为Base64，但是要确保使用相同的算法进行编码和解码。

Answer 3

The byte[] values like the encrypted value, should be Base64 encoded.

        String aesIv2EncryptedString = Base64.encodeToString(aesIv2Encrypted,
            Base64.NO_WRAP);
        jsonObject.addProperty("asIv", aesIv2EncryptedString);

This makes the entire JSON readable UTF-8 text with text values, as Base64 delivers an ASCII subset of the binary data.

---

The encrypt method is as good as perfect, just String.getBytes() (seen in many examples) would use the platform encoding; when this software would ever run on Windows, that encoding would not be UTF-8 but some non-Unicode (= 256 char subset) encoding. Hence characters would be unconvertible ("?") and garbled. So the cross-platform could is:

public String encrypt(String value) throws Exception {
    byte[] encrypted = cipherEnc.doFinal(value.getBytes("UTF-8"));
    return Base64.encodeToString(encrypted, Base64.NO_WRAP);
}

On decryption:

byte[] originalValue = ...;
return new String(originalValue, "UTF-8");