将另一个文件的非 class 函数访问到 Kotlin 中的 class 函数

Question

我刚刚开始使用 Kotlin，我的代码正在执行正常操作。我需要从另一个文件中定义的 class 调用一个函数，而这个文件没有 class。例如，

File1.kt

从该文件调用主函数并定义一个 class 的对象并在此处访问 class 函数，但此 class 是在 File2.kt 中定义的文件。

fun main(args: Array<String>) {
    val secretKey: String = "662ede816988e58fb6d057d9d85605e0"
    val initVector = "de816988e58f"

    var encryptor: AESEncryptor = AESEncryptor()
    val encryptedValue: String? =encryptor.encrypt("This is the first code for encryption in Kotlin.", secretKey, initVector)
    println(encryptedValue)

    val decryptedValue: String? =encryptor.decryptWithAES(secretKey, encryptedValue, initVector)
    println(decryptedValue)
}

File2.kt

此文件中定义了一个 class，此 class 需要访问 File3.kt 文件中定义的函数。

import java.io.UnsupportedEncodingException
import java.security.InvalidKeyException
import java.security.NoSuchAlgorithmException
import javax.crypto.*
import javax.crypto.spec.GCMParameterSpec
import javax.crypto.spec.SecretKeySpec

class AESEncryptor {

    fun encrypt(strToEncrypt: String, secret_key: String, iv_key: String): String? {

        var keyBytes: ByteArray
        var ivKeyBytes: ByteArray

        try {
            keyBytes = secret_key.toByteArray(charset("UTF8"))
            ivKeyBytes = iv_key.toByteArray(charset("UTF8"))
            val skey = SecretKeySpec(keyBytes, "AES")

            val iv = GCMParameterSpec(128, ivKeyBytes, 0, 12)
            val input = strToEncrypt.toByteArray(charset("UTF8"))

            synchronized(Cipher::class.java) {
                val cipher = Cipher.getInstance("AES/GCM/NoPadding")
                cipher.init(Cipher.ENCRYPT_MODE, skey, iv)

                val cipherText = ByteArray(cipher.getOutputSize(input.size))
                var ctLength = cipher.update(
                    input, 0, input.size,
                    cipherText, 0
                )
                ctLength += cipher.doFinal(cipherText, ctLength)
                return cipherText.encodeBase64ToString()
            }
        } catch (uee: UnsupportedEncodingException) {
            uee.printStackTrace()
        } catch (ibse: IllegalBlockSizeException) {
            ibse.printStackTrace()
        } catch (bpe: BadPaddingException) {
            bpe.printStackTrace()
        } catch (ike: InvalidKeyException) {
            ike.printStackTrace()
        } catch (nspe: NoSuchPaddingException) {
            nspe.printStackTrace()
        } catch (nsae: NoSuchAlgorithmException) {
            nsae.printStackTrace()
        } catch (e: ShortBufferException) {
            e.printStackTrace()
        }

        return null
    }

    fun decryptWithAES(key: String, strToDecrypt: String?, iv_key: String): String? {
        //Security.addProvider(BouncyCastleProvider())
        var keyBytes: ByteArray
        var ivKeyBytes: ByteArray
        var encryptor: AESEncryptor = AESEncryptor()
        try {
            keyBytes = key.toByteArray(charset("UTF8"))
            ivKeyBytes = iv_key.toByteArray(charset("UTF8"))
            val skey = SecretKeySpec(keyBytes, "AES")
            //val iv = GCMParameterSpec(ivKeyBytes)
            val iv = GCMParameterSpec(128, ivKeyBytes, 0, 12)

            val input = (strToDecrypt?.trim { it <= ' ' }?.toByteArray(charset("UTF8")))?.decodeBase64()

            synchronized(Cipher::class.java) {
                val cipher = Cipher.getInstance("AES/GCM/NoPadding")
                cipher.init(Cipher.DECRYPT_MODE, skey, iv)

                val plainText = ByteArray(cipher.getOutputSize(input?.size!!))
                var ptLength = cipher.update(input, 0, input?.size!!, plainText, 0)
                ptLength += cipher.doFinal(plainText, ptLength)
                val decryptedString = String(plainText)
                return decryptedString.trim { it <= ' ' }
            }
        } catch (uee: UnsupportedEncodingException) {
            uee.printStackTrace()
        } catch (ibse: IllegalBlockSizeException) {
            ibse.printStackTrace()
        } catch (bpe: BadPaddingException) {
            bpe.printStackTrace()
        } catch (ike: InvalidKeyException) {
            ike.printStackTrace()
        } catch (nspe: NoSuchPaddingException) {
            nspe.printStackTrace()
        } catch (nsae: NoSuchAlgorithmException) {
            nsae.printStackTrace()
        } catch (e: ShortBufferException) {
            e.printStackTrace()
        }

        return null
    }
}

File3.kt

这种形式只定义了一组函数。

import java.io.ByteArrayOutputStream

public fun String.encodeBase64ToString(): String = String(this.toByteArray().encodeBase64())
fun String.encodeBase64ToByteArray(): ByteArray = this.toByteArray().encodeBase64()
fun ByteArray.encodeBase64ToString(): String = String(this.encodeBase64())

fun String.decodeBase64(): String = String(this.toByteArray().decodeBase64())
fun String.decodeBase64ToByteArray(): ByteArray = this.toByteArray().decodeBase64()
fun ByteArray.decodeBase64ToString(): String = String(this.decodeBase64())

public fun ByteArray.encodeBase64(): ByteArray {
    val table = (CharRange('A', 'Z') + CharRange('a', 'z') + CharRange('0', '9') + '+' + '/').toCharArray()
    val output = ByteArrayOutputStream()
    var padding = 0
    var position = 0
    while (position < this.size) {
        var b = this[position].toInt() and 0xFF shl 16 and 0xFFFFFF
        if (position + 1 < this.size) b = b or (this[position + 1].toInt() and 0xFF shl 8) else padding++
        if (position + 2 < this.size) b = b or (this[position + 2].toInt() and 0xFF) else padding++
        for (i in 0 until 4 - padding) {
            val c = b and 0xFC0000 shr 18
            output.write(table[c].toInt())
            b = b shl 6
        }
        position += 3
    }
    for (i in 0 until padding) {
        output.write('='.toInt())
    }
    return output.toByteArray()
}

fun ByteArray.decodeBase64(): ByteArray {
    val table = intArrayOf(-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1,
        -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
        -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1)

    val output = ByteArrayOutputStream()
    var position = 0
    while (position < this.size) {
        var b: Int
        if (table[this[position].toInt()] != -1) {
            b = table[this[position].toInt()] and 0xFF shl 18
        } else {
            position++
            continue
        }
        var count = 0
        if (position + 1 < this.size && table[this[position + 1].toInt()] != -1) {
            b = b or (table[this[position + 1].toInt()] and 0xFF shl 12)
            count++
        }
        if (position + 2 < this.size && table[this[position + 2].toInt()] != -1) {
            b = b or (table[this[position + 2].toInt()] and 0xFF shl 6)
            count++
        }
        if (position + 3 < this.size && table[this[position + 3].toInt()] != -1) {
            b = b or (table[this[position + 3].toInt()] and 0xFF)
            count++
        }
        while (count > 0) {
            val c = b and 0xFF0000 shr 16
            output.write(c.toChar().toInt())
            b = b shl 8
            count--
        }
        position += 4
    }
    return output.toByteArray()
}

我需要使用encodeBase64ToString函数和File2.kt中的其他函数（AESEncryptor.kt）。我能不能做这个？

谁能帮我解决这个问题？

Answer 1

由于您将 File3.kt 中的函数声明为 extension functions，因此您应该以正确的语法使用它们。

所以，不是

return encodeBase64ToString(cipherText)

但是

return cipherText.encodeBase64ToString()

将另一个文件的非 class 函数访问到 Kotlin 中的 class 函数

Access non class functions of another file into a class function in Kotlin

class

function

aes-gcm

kotlin