使用RawFile

参考以下api文档和代码示例：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/app-file-access-V5

// pages/xxx.ets
import fs from ‘@ohos.file.fs’;
import common from ‘@ohos.app.ability.common’;
import buffer from ‘@ohos.buffer’;

// 获取应用文件路径
let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

function createFile(): void {
  // 新建并打开文件
  let file = fs.openSync(filesDir + ‘/test.txt’, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
  // 写入一段内容至文件
  let writeLen = fs.writeSync(file.fd, “Try to write str.”);
  console.info("The length of str is: " + writeLen);
  // 从文件读取一段内容
  let arrayBuffer = new ArrayBuffer(1024);
  class Option {
    public offset: number = 0;
    public length: number = 0;
  }
  let option = new Option();
  option.length = arrayBuffer.byteLength;
  let readLen = fs.readSync(file.fd, arrayBuffer, option);
  let buf = buffer.from(arrayBuffer, 0, readLen);
  console.info("the content of file: " + buf.toString());
  // 关闭文件
  fs.closeSync(file);
}

读取rawfile目录参考：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-resource-manager-V5#getrawfilecontent9

示例代码：

let value: Uint8Array = await context.resourceManager.getRawFileContent(srcPath); 
let str = buffer.from(value.buffer).toString();