Swift如何解码ISO-8859-1（Latin1）字符串并迁移Java解压逻辑？

前置依赖 #

仅使用系统自带框架，无需第三方库，兼容版本：iOS 13.0+/macOS 10.15+/watchOS 6.0+/tvOS 13.0+

• 导入必要框架：

import Foundation
import Compression

完整可运行代码 #

// MARK: Data Zlib解压扩展
extension Data {
    func zlibDecompressed() throws -> Data {
        guard !isEmpty else { return Data() }
        // 初始预估解压后大小为原始数据10倍，不足时自动扩容
        return try zlibDecompressed(expectedSize: count * 10)
    }
    
    private func zlibDecompressed(expectedSize: Int) throws -> Data {
        var decompressedData = Data(count: expectedSize)
        let result = decompressedData.withUnsafeMutableBytes { destBuffer in
            self.withUnsafeBytes { srcBuffer in
                compression_decode_buffer(
                    destBuffer.baseAddress!.assumingMemoryBound(to: UInt8.self),
                    destBuffer.count,
                    srcBuffer.baseAddress!.assumingMemoryBound(to: UInt8.self),
                    srcBuffer.count,
                    nil,
                    COMPRESSION_ZLIB
                )
            }
        }
        guard result > 0 else {
            throw NSError(domain: "ZlibError", code: -1, userInfo: [NSLocalizedDescriptionKey: "Zlib解压失败，数据格式错误"])
        }
        // 缓冲区足够容纳解压结果，裁剪多余空间
        if result < expectedSize {
            decompressedData.count = result
            return decompressedData
        }
        // 缓冲区不足，扩大后重试
        return try zlibDecompressed(expectedSize: expectedSize * 2)
    }
}

// MARK: 核心处理逻辑，对应Java的两步处理流程
func parseCompressedJson(encodedStr: String) throws -> Any {
    // 第一步：对应Java URLDecoder.decode(data, "ISO-8859-1")
    guard let urlDecodedStr = encodedStr.removingPercentEncoding,
          let compressedData = urlDecodedStr.data(using: .isoLatin1) else {
        throw NSError(domain: "DecodeError", code: -2, userInfo: [NSLocalizedDescriptionKey: "URL解码失败，编码格式不符"])
    }
    // 第二步：Zlib解压
    let rawData = try compressedData.zlibDecompressed()
    // 转换为JSON对象，支持字典/数组两种结构
    return try JSONSerialization.jsonObject(with: rawData)
}

调用示例 #

do {
    // 替换为你实际的原始编码字符串
    let rawInput = "你的ISO-8859-1编码的原始数据源字符串"
    let jsonResult = try parseCompressedJson(encodedStr: rawInput)
    
    // 若已知JSON为字典结构，可直接转换
    if let jsonDict = jsonResult as? [String: Any] {
        print("解析得到的JSON字典：\(jsonDict)")
    }
    // 若已知JSON为数组结构，可转换为数组
    else if let jsonArray = jsonResult as? [Any] {
        print("解析得到的JSON数组：\(jsonArray)")
    }
} catch {
    print("处理失败：\(error.localizedDescription)")
}

逻辑对应说明 #

• Java端URLDecoder.decode(data, "ISO-8859-1") 对应Swift端 encodedStr.removingPercentEncoding + 转.isoLatin1编码的Data，两者逻辑完全对齐
• Java端Inflater解压对应Swift系统Compression框架的compression_decode_buffer方法，使用COMPRESSION_ZLIB格式适配标准zlib压缩数据

内容的提问来源于stack exchange，提问作者dengST30