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介绍

本示例通过util模块下的textDecoder和textEncoder对文本进行编解码，统一自带toString编码方式及TestEncoder支持的编码方式。

实现文本编解码功能源码链接

效果预览

使用说明

点击对应模式按钮即可展示结果。

实现思路

1. 支持方式汇总。

static BUFFER_ENCODING: string[] =
  ['ascii', 'utf8', 'utf-8', 'utf16le', 'ucs2', 'ucs-2', 'base64', 'base64url', 'latin1', 'binary', 'hex'];
static TEXT_ENCODING: string[] =
  ['utf-8ibm866', 'iso-8859-2', 'iso-8859-3', 'iso-8859-4', 'iso-8859-5', 'iso-8859-6', 'iso-8859-7', 'iso-8859-8',
    'iso-8859-8-i', 'iso-8859-10', 'iso-8859-13', 'iso-8859-14', 'iso-8859-15', 'koi8-r', 'koi8-u', 'macintosh',
    'windows-874', 'windows-1250', 'windows-1251', 'windows-1252', 'windows-1253', 'windows-1254', 'windows-1255',
    'windows-1256', 'windows-1257', 'windows-1258', 'x-mac-cyrillic', 'gbk', 'gb18030', 'big5', 'euc-jp',
    'iso-2022-jp', 'shift_jis', 'euc-kr', 'utf-16be', 'utf-16le', 'UTF-8', 'GBK', 'GB2312', 'gb2312', 'GB18030',
    'iso-8859-1']

2. decodeBufferToString()与encodeToBuffer()分别调用textDecoder和textEncoder对文本进行编解码。

// 解码
public static decodeBufferToString(buf: buffer.Buffer, encoding: string): string {
    let lowerCaseEncoding = encoding.toLowerCase();
    if (BufferUtil.BUFFER_ENCODING.indexOf(lowerCaseEncoding) != -1) {
      return buf.toString(lowerCaseEncoding)
    }
    if (BufferUtil.TEXT_ENCODING.indexOf(encoding) === -1) {
      throw new Error(`Currently, encoding ${encoding} is not supported`);
    }
    return BufferUtil.decodeBufferToStringByTextDecoder(buf, encoding)
  }
//编码
  public static encodeToBuffer(str: string, encoding: string): buffer.Buffer {
    let lowerCaseEncoding = encoding.toLowerCase();
    if (BufferUtil.BUFFER_ENCODING.indexOf(lowerCaseEncoding) != -1) {
      return buffer.from(str, lowerCaseEncoding as buffer.BufferEncoding);
    }
    if (BufferUtil.TEXT_ENCODING.indexOf(encoding) === -1) {
      throw new Error(`Currently, encoding ${encoding} is not supported`);
    }
    return BufferUtil.encodeToBufferByTextEncoder(str, encoding)
  }
//使用TextDecoder解码
  private static decodeBufferToStringByTextDecoder(buf: buffer.Buffer, encoding: string): string {
    let textDecoderOptions: util.TextDecoderOptions = {
      fatal: false,
      ignoreBOM: true
    }
    let textDecoder = util.TextDecoder.create(encoding, textDecoderOptions);
    return textDecoder.decodeToString(new Uint8Array(buf.buffer));
  }
//使用TextEncoder编码
  private static encodeToBufferByTextEncoder(str: string, encoding: string): buffer.Buffer {
    let textEncoder = new util.TextEncoder(encoding);
    let result = textEncoder.encodeInto(str);
    return buffer.from(result);
  }

3. 演示页面，对输入文本编解码。

TextInput({ text: this.inputText, placeholder: '请输入文本' })
  .onChange((value: string) => {
    this.inputText = value
  })
  .margin({top:20})

  Column(){
    Button('Encode to Buffer')
      .onClick(()=>{
        this.outputBuffer=BufferUtil.encodeToBuffer(this.inputText,'GB18030')
        this.outputText='Encode Buffer:'+this.outputBuffer
      })
      .margin({top:20})
    Button('Decode Buffer to String')
      .onClick(()=>{
        if(this.outputBuffer){
          this.outputText=BufferUtil.decodeBufferToString(this.outputBuffer,'GB18030')
        }else{
          this.outputText='No buffer to decode'
        }
      })
      .margin({top:10})
  }
  .margin({top:20})

  Text(this.outputText)
    .fontSize(16)
    .margin({top:30})
}