<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>base64转pdf</title>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.js"></script>
<!-- <style>
iframe {
height: 800px;
800px
}
</style> -->
</head>
<body>
<div>
<a class="down" href=""></a>
</div>
<button onclick="myFunction()">download Img</button>
<button onclick="myFunction2()">download pdf </button>
</body>
<script>
function myFunction() {
let base64 = 'data:image/png;base64,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';
function dataURLtoBlob(dataurl) {
var arr = dataurl.split(','),
mime = arr[0].match(/:(.*?);/)[1],
bstr = atob(arr[1]),
n = bstr.length,
u8arr = new Uint8Array(n);
while (n--) {
u8arr[n] = bstr.charCodeAt(n);
}
return new Blob([u8arr], { type: mime });
}
//调用
let blob = dataURLtoBlob(base64);
let link = document.createElement('a')
link.download = 'abc.pdf' // 要下载的文件名
link.href = URL.createObjectURL(blob);
// 触发点击
document.body.appendChild(link);
link.click();
// 然后移除
document.body.removeChild(link);
}
/**
* desc: base64对象转blob文件对象
* @param urlData ：数据的base64对象
* @param type ：类型 png,pdf,doc,mp3等;
* @returns {Blob}：Blob文件对象
*/
function base64ToBlob(urlData, type) {
let arr = urlData.split(',');
let array = arr[0].match(/:(.*?);/);
let mime = (array && array.length > 1 ? array[1] : type) || type;
// 去掉url的头，并转化为byte
let bytes = window.atob(arr[1]);
// 处理异常,将ascii码小于0的转换为大于0
let ab = new ArrayBuffer(bytes.length);
// 生成视图（直接针对内存）：8位无符号整数，长度1个字节
let ia = new Uint8Array(ab);
for (let i = 0; i < bytes.length; i++) {
ia[i] = bytes.charCodeAt(i);
}
return new Blob([ab], {
type: mime
});
}
/**
* desc: 下载导出文件
* @param blob ：返回数据的blob对象或链接
* @param fileName ：下载后文件名标记
* @param fileType ：文件类 word(docx) excel(xlsx) ppt等
*/
function downloadExportFile(blob, fileName, fileType) {
let downloadElement = document.createElement('a');
let href = blob;
if (typeof blob == 'string') {
downloadElement.target = '_blank';
} else {
href = window.URL.createObjectURL(blob); //创建下载的链接
}
downloadElement.href = href;
downloadElement.download = fileName + '.' + fileType; //下载后文件名
document.body.appendChild(downloadElement);
downloadElement.click(); //触发点击下载
document.body.removeChild(downloadElement); //下载完成移除元素
if (typeof blob != 'string') {
window.URL.revokeObjectURL(href); //释放掉blob对象
}
}
/**
* desc: base64转文件并下载
* @param base64 {String} : base64数据
* @param fileType {String} : 要导出的文件类型png,pdf,doc,mp3等
* @param fileName {String} : 文件名
*/
function downloadFile(base64, fileName, fileType) {
let typeHeader = 'data:application/' + fileType + ';base64,' // 定义base64 头部文件类型
let converedBase64 = typeHeader + base64; // 拼接最终的base64
let blob = base64ToBlob(converedBase64, fileType) // 转成blob对象
downloadExportFile(blob, fileName, fileType) // 下载文件
}
function myFunction2() {
downloadFile("base64","123.pdf","pdf");
}
</script>
</html>
