需求：加載驗(yàn)證碼；1.下載驗(yàn)證碼圖像文件；2.獲取header里面驗(yàn)證碼ID

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根據(jù)文檔使用 request.downloadFile 請(qǐng)求，官方示例:

// pages/xxx.ets
// 將網(wǎng)絡(luò)資源文件下載到應(yīng)用文件目錄并讀取一段內(nèi)容
import common from '@ohos.app.ability.common';
import fs from '@ohos.file.fs';
import request from '@ohos.request';

// 獲取應(yīng)用文件路徑
let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

try {
  request.downloadFile(context, {
    url: 'https://xxxx/xxxx.txt',
    filePath: filesDir + '/xxxx.txt'
  }).then((downloadTask) = > {
    downloadTask.on('complete', () = > {
      console.info('download complete');
      let file = fs.openSync(filesDir + '/xxxx.txt', fs.OpenMode.READ_WRITE);
      let buf = new ArrayBuffer(1024);
      let readLen = fs.readSync(file.fd, buf);
      console.info(`The content of file: ${String.fromCharCode.apply(null, new Uint8Array(buf.slice(0, readLen)))}`);
      fs.closeSync(file);
    })
  }).catch((err) = > {
    console.error(`Invoke downloadTask failed, code is ${err.code}, message is ${err.message}`);
  });
} catch (err) {
  console.error(`Invoke downloadFile failed, code is ${err.code}, message is ${err.message}`);
}復(fù)制

里面存在一個(gè)解決不到的問(wèn)題是，獲取不到header里面驗(yàn)證碼ID，downloadTask 無(wú)法獲取....只能換常規(guī)方法獲取了。

換 httpRequest.request 來(lái)請(qǐng)求，示例代碼如下：

/**
   * 下載文件(驗(yàn)證碼使用)
   */
  static httpFileDownload(url: string, params?: any): Promise< ResponseResultJson > {
    LogUtils.i("下載文件URL：" + url + "n請(qǐng)求參數(shù):" + (params != undefined ? "n請(qǐng)求參數(shù):" + JSON.stringify(params) : "無(wú)參數(shù)"));
    //
    let httpRequest = http.createHttp();
    httpRequest.on('headersReceive', (header) = > {
      //用于訂閱HTTP響應(yīng)頭，此接口會(huì)比request請(qǐng)求先返回。可以根據(jù)業(yè)務(wù)需要訂閱此消息
    });
    //
    let responseResult = httpRequest.request(url, {
      method: http.RequestMethod.GET,
      readTimeout: RequestConstants.readTimeout,
      connectTimeout: RequestConstants.connectTimeout,
      header: {
        'Content-Type': ContentType.JSON
      },
      expectDataType: http.HttpDataType.ARRAY_BUFFER, // 可選，指定返回?cái)?shù)據(jù)的類(lèi)型
      extraData: params
    });
    let responseResultJson = new ResponseResultJson();
    return responseResult.then(async (responseResult: http.HttpResponse) = > {
      LogUtils.i("文件下載請(qǐng)求響應(yīng)URL：" + url + "n響應(yīng)結(jié)果:" + "n" + JSON.stringify(responseResult));
      if (responseResult.responseCode === ResponseConstants.RESPONSE_SUCCESS) {
        let header = responseResult.header
        LogUtils.i('解析響應(yīng) header n' + JSON.stringify(header));
        let headerJson = JSON.stringify(header)
        let headerObj = JSON.parse(headerJson)
        let sessionId = headerObj.sessionid as string
        let serverModel = headerObj.servermodel as string
        let encryptType = headerObj.encrypttype as string
        //保存 header
        await AppHelper.commitSessionId(sessionId);
        await AppHelper.commitServerModel(serverModel);
        await AppHelper.commitEncryptType(encryptType);
        //解析文件
        let result = responseResult.result as ArrayBuffer
        // let filePath = FileConstants.rootFile + "/verifyCode_" + TimeExUtils.getNowYMDHMS1() + '.jpg'
        let isHave = fs.accessSync(FileConstants.pathFile) //檢查文件目錄是否存在
        if (!isHave) fs.mkdirSync(FileConstants.pathFile) //創(chuàng)建目錄
        //
        let filePath = FileConstants.pathFile + "verifyCode_" + TimeExUtils.getNowYMDHMS1() + '.jpg'
        let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
        fs.writeSync(file.fd, result); //將數(shù)據(jù)寫(xiě)入文件
        fs.closeSync(file); //關(guān)閉文件
        //
        LogUtils.i("保存文件成功:n" + filePath + "t" + await FileUtils.getPathSize(filePath));
        //結(jié)果
        responseResultJson.code = ResponseConstants.CODE_SUCCESS
        responseResultJson.isSuccess = true
        responseResultJson.status = responseResult.responseCode
        responseResultJson.serverModel = serverModel
        responseResultJson.filePath = filePath
      } else {
        responseResultJson.code = ResponseConstants.CODE_ERROR;
        responseResultJson.message = "業(yè)務(wù)異常:" + JSON.stringify(responseResult)
        responseResultJson.isSuccess = false
      }
      return responseResultJson;
    }).catch((error) = > {
      LogUtils.i("文件下載請(qǐng)求響應(yīng)URL：" + url + "n請(qǐng)求異常:n" + JSON.stringify(error))
      responseResultJson.code = ResponseConstants.CODE_ERROR;
      responseResultJson.message = "請(qǐng)求異常:n" + JSON.stringify(error)
      responseResultJson.isSuccess = false
      return responseResultJson;
    });
  }復(fù)制

里面無(wú)用工具類(lèi)可以不用在意...里面獲取header可以有2種方法

方法一：

資料拿取+mau123789是v喔
 httpRequest.on('headersReceive', (header) = > {
      //用于訂閱HTTP響應(yīng)頭，此接口會(huì)比request請(qǐng)求先返回。可以根據(jù)業(yè)務(wù)需要訂閱此消息
    });

方法二：

let header = responseResult.header
        LogUtils.i('解析響應(yīng) header n' + JSON.stringify(header));
        let headerJson = JSON.stringify(header)
        let headerObj = JSON.parse(headerJson)
        let sessionId = headerObj.sessionid as string
        let serverModel = headerObj.servermodel as string
        let encryptType = headerObj.encrypttype as string

獲取的值是一樣的。

獲取驗(yàn)證碼文件關(guān)鍵代碼：

1.參數(shù)里面的 expectDataType 需要設(shè)置為 http.HttpDataType.ARRAY_BUFFER；

2. 結(jié)果轉(zhuǎn)換為ArrayBuffer，let result = responseResult.result as ArrayBuffer

運(yùn)行日志：

運(yùn)行效果：

完畢啦！！！！ 驗(yàn)證碼獲取成功了！！！！

審核編輯 黃宇