HarmonyOS 鸿蒙Next LZ4解压缩文本

这里使用的commons-compress 三方库 进行的LZ4格式 压缩 解压 当前仅 commons-compress 三方库 支持此能力 但是这个库不能对string 进行解压 但是可以对压缩包进行解压

/*

 * Copyright (c) 2022 Huawei Device Co., Ltd.

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

import { lz4Compressed, lz4Decompressed, System } from '[@ohos](/user/ohos)/commons-compress';

import fs from '[@ohos](/user/ohos).file.fs';

import { GlobalContext } from './GlobalContext';

import common from '[@ohos](/user/ohos).app.ability.common';

let context = getContext(this) as common.UIAbilityContext;

[@Entry](/user/Entry)

[@Component](/user/Component)

export struct Lz4Test {

  TAG: string = 'lz4Test----'

  [@State](/user/State) isCompressLz4Show: boolean = false;

  [@State](/user/State) isDeCompressLz4Show: boolean = false;

  preTimestamp: number = 0;

  build() {

    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {

      Text('lz4相关功能')

        .fontSize(20)

        .margin({ top: 16 })

      Text('点击生成test.txt')

        .fontSize(16)

        .margin({ top: 32 })

        .padding(8)

        .border({ width: 2, color: '#535353', radius: 6 })

        .onClick((event) => {

          if (!this.isFastClick()) {

            this.generateTextFile()

          }

        })

      if (true) {

        Text('点击压缩test.txt为lz4文件')

          .fontSize(16)

          .margin({ top: 32 })

          .padding(8)

          .border({ width: 2, color: '#535353', radius: 6 })

          .onClick((event) => {

            if (!this.isFastClick()) {

              this.lz4CompressedTest()

            }

          })

      }

      if (true) {

        Text('点击解压lz4文件')

          .fontSize(16)

          .margin({ top: 32 })

          .padding(8)

          .border({ width: 2, color: '#535353', radius: 6 })

          .onClick((event) => {

            if (!this.isFastClick()) {

              this.lz4DecompressedTest()

            }

          })

      }

    }

    .width('100%')

    .height('100%')

  }

  isFastClick(): boolean {

    let timestamp:number = Date.parse(new Date().toString());

    if ((timestamp - this.preTimestamp) > 1500) {

      this.preTimestamp = timestamp;

      return false;

    } else {

      return true;

    }

  }

  generateTextFile(): void {

    try {

      let data = getContext(this).filesDir

      // let data = context.filesDir

      const writer = fs.openSync(data + '/aaaaa.txt', fs.OpenMode.WRITE_ONLY | fs.OpenMode.CREATE);

      fs.writeSync(writer.fd, "xxx"

      );

      fs.closeSync(writer);

      AlertDialog.show({ title: '生成成功',

        message: '请查看沙箱路径' + data + '/aaaaa.txt',

        confirm: { value: 'OK', action: () => {

          this.isCompressLz4Show = true

        } }

      })

    } catch (error) {

      console.error('File to obtain the file directory. Cause: ' + error.message);

    }

  }

  lz4CompressedTest(): void {

    try {

      let data = getContext(this).filesDir

      // let data = context.filesDir

      let timer1 = System.currentTimeMillis().toString()

      console.info(this.TAG + timer1)

      lz4Compressed(data + '/aaaaa.txt', data + '/aaaaa.txt.lz4')

      let timer2: string = System.currentTimeMillis().toString()

      console.info(this.TAG + timer2)

      AlertDialog.show({ title: '压缩成功',

        message: '请查看沙箱路径 ' + data + '/aaaaa.txt.lz4',

        confirm: { value: 'OK', action: () => {

          this.isDeCompressLz4Show = true

        } }

      })

    } catch (error) {

      console.error('File to obtain the file directory. Cause: ' + error.message);

    }

  }

  lz4DecompressedTest(): void {

    try {

      let data = getContext(this).filesDir

      // let data = context.filesDir

      let timer1 = System.currentTimeMillis().toString()

      console.info(this.TAG + timer1)

      lz4Decompressed(data + '/aaaaa.txt.lz4', data + '/aaaaabv.txt')

      let timer2: string = System.currentTimeMillis().toString()

      console.info(this.TAG + timer2)

      AlertDialog.show({ title: '解缩成功',

        message: '请查看沙箱路径 ' + data + '/aaaaabv.txt',

        confirm: { value: 'OK', action: () => {

        } }

      })

    } catch (error) {

      console.error('File to obtain the file directory. Cause: ' + error.message);

    }

  }

}

当前LZ4的压缩解压 仅commons-compress 三方库支持 仅对文件解压缩  不支持对字符串进行解压缩  目前鸿蒙自带的解压缩 不支持LZ4格式