将大量数据导出到 csv 文件 - 崩溃

Question

我正在尝试将大数据导出到 csv 文件。 （超过 20000 行......可以轻松达到超过 100000 行）。在我尝试下载文件后，它崩溃了 - 由于网络故障，下载失败。 （设法下载了一个 18000 行的文件，重 1.7MB，代码运行良好。超过 20000 下载崩溃）

这是我的代码...谢谢！

edit-适用于 IE，不适用于 chrome

var data2 =     [[data12]];
var csvContent2 = "";
data2.forEach(function (infoArray, index) {

    dataString = Array.prototype.join.call(infoArray, "");
    csvContent2 += index < data2.length ? dataString + '\n' : dataString;

});

var download = function(content, fileName, mimeType) {
var a = document.createElement('a');
    mimeType = mimeType || 'application/octet-stream';

    if (navigator.msSaveBlob) { // IE10
        return navigator.msSaveBlob(new Blob([content], { type: mimeType }), fileName);
    } else if ('download' in a) { //html5 A[download]
        a.href = 'data:' + mimeType + ',' + encodeURIComponent(content);
        a.setAttribute('download', fileName);
        document.body.appendChild(a);
        setTimeout(function() {
        a.click();
        document.body.removeChild(a);
        }, 66);
    return true;
} else { //do iframe dataURL download (old ch+FF):
    var f = document.createElement('iframe');
    document.body.appendChild(f);
    f.src = 'data:' + mimeType + ',' + encodeURIComponent(content);

    setTimeout(function() {
        document.body.removeChild(f);
    }, 333);
    return true;
    }
}

    download(csvContent2, 'GroupB.csv', 'text/csv');

Answer 1

警告，URL 有一些限制，例如，包括 GET 在内的 URL 总长度，在 IE 上不得超过 2000+ 个字符，也许你会使用大的 CSV 文件达到最大大小？
你的 URI 有多长？见this link about IE URI limit。

编辑： 也许你可以试试这个createObjectURL(blob)，但这不是一个稳定的功能：x

Answer 2

没关系，只是使用了这个脚本，来自这个网络-http://jsfiddle.net/4zv6r/

           function cloneAndConvert(){

var jsonData = [{firstName:"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum", lastName:"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum", age:46}];
for(i=0;i<90000;i++)
{     
   jsonData.push({firstName:"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum"+i, lastName:"Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum"+i, age:46});
}

var filteredGridData = JSON.parse(JSON.stringify(jsonData))
JSONToCSVConvertor(filteredGridData, "UserReport.csv", true);

}

function JSONToCSVConvertor(JSONData, ReportTitle, ShowLabel) {

//If JSONData is not an object then JSON.parse will parse the JSON string in an Object
var arrData = typeof JSONData != 'object' ? JSON.parse(JSONData) : JSONData;
var CSV = '';    
//This condition will generate the Label/Header
if (ShowLabel) {
    var row = "";

    //This loop will extract the label from 1st index of on array
    for (var index in arrData[0]) {
        //Now convert each value to string and comma-seprated
        row += index + ',';
    }
    row = row.slice(0, -1);
    //append Label row with line break
    CSV += row + '\r\n';
}

//1st loop is to extract each row
for (var i = 0; i < arrData.length; i++) {
    var row = "";
    //2nd loop will extract each column and convert it in string comma-seprated
    for (var index in arrData[i]) {
        row += '"' + arrData[i][index] + '",';
    }
    row.slice(0, row.length - 1);
    //add a line break after each row
    CSV += row + '\r\n';
}

if (CSV == '') {        
    alert("Invalid data");
    return;
}   

//this trick will generate a temp "a" tag
var link = document.createElement("a");    
link.id="lnkDwnldLnk";

//this part will append the anchor tag and remove it after automatic click
document.body.appendChild(link);

var csv = CSV;  
blob = new Blob([csv], { type: 'text/csv' }); 
var csvUrl = window.webkitURL.createObjectURL(blob);
var filename = 'UserExport.csv';
$("#lnkDwnldLnk")
.attr({
    'download': filename,
    'href': csvUrl
}); 

$('#lnkDwnldLnk')[0].click();    
document.body.removeChild(link);

}

Answer 3

如果您正在处理大量数据，那么您可能想寻找一种方法来处理 使用StreamSaver处理内存更友好

async function download(){
    const fileStream = streamSaver.createWriteStream('filename.csv')
    const writer = fileStream.getWriter()
    const encoder = new TextEncoder

    for(let row of rows){
        await writer.ready()
        let binary = encoder.encode(data + "\r\n")
        writer.write(uint8array)
    }

    writer.close()
}