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HTML5 Blob与ArrayBuffer、TypeArray和字符串String之间转换

1.将String字符串转换成Blob对象

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//将字符串 转换成 Blob 对象
var blob = new Blob(["Hello World!"], {
    type: 'text/plain'
});
console.info(blob);
console.info(blob.slice(1, 3, 'text/plain'));

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2.将TypeArray  转换成 Blob 对象

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//将 TypeArray  转换成 Blob 对象
var array = new Uint16Array([97, 32, 72, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100, 33]);
//测试成功
//var blob = new Blob([array], { type: "application/octet-binary" });
//测试成功， 注意必须[]的包裹
var blob = new Blob([array]);
//将 Blob对象 读成字符串
var reader = new FileReader();
reader.readAsText(blob, 'utf-8');
reader.onload = function (e) {
    console.info(reader.result); //a Hello world!
}

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ArrayBuffer转Blob

 

var buffer = new ArrayBuffer(32);
var blob = new Blob([buffer]);       // 注意必须包裹[]

 

 

 

3，将Blob对象转换成String字符串，使用FileReader的readAsText方法

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//将字符串转换成 Blob对象
var blob = new Blob(['中文字符串'], {
    type: 'text/plain'
});
//将Blob 对象转换成字符串
var reader = new FileReader();
reader.readAsText(blob, 'utf-8');
reader.onload = function (e) {
    console.info(reader.result);
}

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4.将Blob对象转换成ArrayBuffer，使用FileReader的 readAsArrayBuffer方法

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//将字符串转换成 Blob对象
var blob = new Blob(['中文字符串'], {
    type: 'text/plain'
});
//将Blob 对象转换成 ArrayBuffer
var reader = new FileReader();
reader.readAsArrayBuffer(blob);
reader.onload = function (e) {
    console.info(reader.result); //ArrayBuffer {}
    //经常会遇到的异常 Uncaught RangeError: byte length of Int16Array should be a multiple of 2
    //var buf = new int16array(reader.result);
    //console.info(buf);

    //将 ArrayBufferView  转换成Blob
    var buf = new Uint8Array(reader.result);
    console.info(buf); //[228, 184, 173, 230, 150, 135, 229, 173, 151, 231, 172, 166, 228, 184, 178]
    reader.readAsText(new Blob([buf]), 'utf-8');
    reader.onload = function () {
        console.info(reader.result); //中文字符串
    };

    //将 ArrayBufferView  转换成Blob
    var buf = new DataView(reader.result);
    console.info(buf); //DataView {}
    reader.readAsText(new Blob([buf]), 'utf-8');
    reader.onload = function () {
        console.info(reader.result); //中文字符串
    };
}

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关于Blob对象，请参考：http://www.cnblogs.com/tianma3798/p/4293660.html

 

Uint8Array转字符串

function Uint8ArrayToString(fileData){
  var dataString = "";
  for (var i = 0; i < fileData.length; i++) {
    dataString += String.fromCharCode(fileData[i]);
  }
 
  return dataString
}


字符串转Uint8Array

function stringToUint8Array(str){
  var arr = [];
  for (var i = 0, j = str.length; i < j; ++i) {
    arr.push(str.charCodeAt(i));
  }
 
  var tmpUint8Array = new Uint8Array(arr);
  return tmpUint8Array
}


 int转byte[]

function intTobytes2(n) {
  var bytes = [];
 
  for (var i = 0; i < 2; i++) {
    bytes[i] = n >> (8 - i * 8);
 
  }
  return bytes;
}
 

string转ArrayBuffer

function str2ab(str) {
  var buf = new ArrayBuffer(str.length * 2); // 每个字符占用2个字节
  var bufView = new Uint16Array(buf);
  for (var i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}


ArrayBuffer转String

function ab2str(buf) {
  return String.fromCharCode.apply(null, new Uint8Array(buf));
}
  

Uint16Array to Uint8Array 

data_16=new Uint16Array([4]);
 
//data_8 = new Uint8Array(data_16);//byteLength改变

data_8 = new Uint8Array(data_16.buffer);//byteLength不变

转载于：https://www.cnblogs.com/tianma3798/p/5834598.html

               https://blog.csdn.net/LightUpHeaven/article/details/81240862

              https://stackoverflow.com/questions/27038704/uint16array-to-uint8array

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