如何从CipherInputStream中提取数据？

Question

我解密内部存储器上的文件，如下所示：

CipherInputStream cip = new CipherInputStream(context.openFileInput("filename"), cipher);

如何获取解码结果并将其转换为字符串？

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更新

存储在手机内存中的文件是加密的json文件。该方法应读取此文件，解密并将结果作为字符串返回：

public String getJSON() {
            String jsonString = "";

    try {
            String algorithm = "DESede";
            jsonString = "";
            SecretKeyFactory skf = SecretKeyFactory.getInstance(algorithm);
            DESedeKeySpec kspec = new DESedeKeySpec(readKey().getBytes());
            SecretKey key = skf.generateSecret(kspec);
            Cipher cipher = Cipher.getInstance(algorithm);
            cipher.init(Cipher.DECRYPT_MODE, key);
            CipherInputStream cip = new CipherInputStream(context.openFileInput("filename"), cipher);

            // here I have to get the result of decoding and write it to the jsonString

            cip.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
        return jsonString;
    }