说明：开发环境 vs2012 mvc4项目，后台语言csharp
1、前端代码
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<title>图片上传测试</title>
</head>
<body>
<form action="/Home/MultiSavePage" enctype="multipart/form-data" method="post">
<input type="file" name="files" id="file1" onchange="checkPic(this)" /><br/>
<input type="file" name="files" id="file2" onchange="checkPic(this)"/><br/>
<input type="file" name="files" id="file3" onchange="checkPic(this)"/><br/>
<input type="submit" value="同时上传多个文件" />
</form>
<script type="text/javascript">
function checkPic(e) {
if (!e || !e.value) return;
var patn = /.jpg$|.jpeg$|.png$|.gif$/i;
if (!patn.test(e.value)) {
alert("您选择的似乎不是图像文件。");
e.value = "";
return;
}
else {
//以下的代码可以 把选中的图片 放到img中显示
var $file = $(e);
var fileObj = $file[0];
var windowURL = window.URL || window.webkitURL;
var dataURL;
//var $img = $("#"+id+"");
if (fileObj && fileObj.files && fileObj.files[0]) {
dataURL = windowURL.createObjectURL(fileObj.files[0]);
console.log(dataURL);
//$img.attr('src', dataURL);
}
}
}
</script>
</body>
</html>
2、控制器代码
action="/Home/MultiSavePage" 对应的后台代码
（1）、正常保存图片，不对图片压缩处理
public void MultiSavePage(IEnumerable<HttpPostedFileBase> files)
{
Int32 count = files.Count();
Int32 pid = 56;
Int32 offid = 100;
string str = "GX";
string pathForSaving = Server.MapPath("~/img");
string pagePath = pathForSaving + "/" + offid + "/" + str + "/" + pid;
if (this.CreateFolderIfNeeded(pagePath))
{
foreach (var file in files)
{
if (file != null && file.ContentLength > 0)
{
string[] picName = file.FileName.Split('.');
//判断文件的类型
if (picName[1] == "jpg" || picName[1] == "gif" || picName[1] == "png" || picName[1] == "bmg" || picName[1] == "jpeg")
{
//给上传文件重命名
string filename = DateTime.Now.ToString("yyyyMMddHHmmssfff") + Guid.NewGuid().ToString();
//文件保存的路径
string filesavepath = filename + "." + picName[1];
//保存图片
//var path = Path.Combine(pathForSaving, file.FileName);
var path = Path.Combine(pagePath, filename + "." + picName[1]);
file.SaveAs(path);
}
}
}
}
}
注释：
string pathForSaving = Server.MapPath("~/img"); img是项目文件夹，上传的图片都保存到img文件夹下
（2）、对上传的图片压缩处理，并且把图片保存为png格式
public void MultiSavePage(IEnumerable<HttpPostedFileBase> files)
{
Int32 count = files.Count();
Int32 pid = 56;
Int32 offid = 100;
string str = "GX";
string pathForSaving = Server.MapPath("~/img");
string pagePath = pathForSaving + "/" + offid + "/" + str + "/" + pid;
if (this.CreateFolderIfNeeded(pagePath))
{
foreach (var file in files)
{
if (file != null && file.ContentLength > 0)
{
string[] picName = file.FileName.Split('.');
//判断文件的类型
if (picName[1] == "jpg" || picName[1] == "gif" || picName[1] == "png" || picName[1] == "bmg" || picName[1] == "jpeg")
{
//给上传文件重命名
string filename = DateTime.Now.ToString("yyyyMMddHHmmssfff") + Guid.NewGuid().ToString();
//文件保存的路径
string filesavepath = filename + "." + picName[1];
//保存图片
//var path = Path.Combine(pathForSaving, file.FileName);
var path = Path.Combine(pagePath, filename + "." + picName[1]);
//file.SaveAs(path);
Bitmap bitmapTem = (Bitmap)Image.FromStream(file.InputStream);//file图片文件转换为bitmap
//压缩图片
Bitmap bitmapLast = ZoomImage(bitmapTem, 331, 600);
bitmapLast.Save(path, System.Drawing.Imaging.ImageFormat.Png);
}
}
}
}
}
3、用到的其他方法
// 检查是否要创建上传文件夹
private bool CreateFolderIfNeeded(string path)
{
bool result = true;
if (!Directory.Exists(path))
{
try
{
Directory.CreateDirectory(path);
}
catch (Exception)
{
//TODO:处理异常
result = false;
}
}
return result;
}
4、压缩图片的方法
using System.Drawing;
//等比例缩放图片
//destHeight 331 destWidth 600
private Bitmap ZoomImage(Bitmap bitmap, int destHeight, int destWidth)
{
try
{
System.Drawing.Image sourImage = bitmap;
int width = 0, height = 0;
//按比例缩放
int sourWidth = sourImage.Width;
int sourHeight = sourImage.Height;
if (sourHeight > destHeight || sourWidth > destWidth)
{
if ((sourWidth * destHeight) > (sourHeight * destWidth))
{
width = destWidth;
height = (destWidth * sourHeight) / sourWidth;
}
else
{
height = destHeight;
width = (sourWidth * destHeight) / sourHeight;
}
}
else
{
width = sourWidth;
height = sourHeight;
}
Bitmap destBitmap = new Bitmap(destWidth, destHeight);
Graphics g = Graphics.FromImage(destBitmap);
g.Clear(Color.Transparent);
//设置画布的描绘质量
g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.DrawImage(sourImage, new Rectangle((destWidth - width) / 2, (destHeight - height) / 2, width, height), 0, 0, sourImage.Width, sourImage.Height, GraphicsUnit.Pixel);
g.Dispose();
//设置压缩质量
System.Drawing.Imaging.EncoderParameters encoderParams = new System.Drawing.Imaging.EncoderParameters();
long[] quality = new long[1];
quality[0] = 100;
System.Drawing.Imaging.EncoderParameter encoderParam = new System.Drawing.Imaging.EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
encoderParams.Param[0] = encoderParam;
sourImage.Dispose();
return destBitmap;
}
catch
{
return bitmap;
}
}