java 上传并压缩图片

protected Map<String, Object> upload(MultipartHttpServletRequest req) throws IOException {
String root = PropertiesHelper.getProperty("upload_photo_root");
String tempPath = PropertiesHelper.getProperty("upload_photo_path");
Map<String, Object> result = new HashMap<String, Object>();
if (req.getFile("uploadFile") != null) {
MultipartFile file = req.getFile("uploadFile");

BufferedImage newImage=getNewImage(file,548,381);

if (file.getSize() > 0) {
String path = root + tempPath;
path = path.replace('\\', '/');
File directory = new File(path);
if (!directory.exists()) {
directory.mkdirs();
}
String pre = "RID" + req.getParameter("reportId") + "_"
+ String.valueOf(System.currentTimeMillis());
// File destFile = new File(path + pre +
// file.getOriginalFilename().toLowerCase());

// String fileType =
// file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf("."));
String fileType = ".png";
File destFile = new File(path + pre + fileType);
try {
//FileUtils.writeByteArrayToFile(destFile, file.getBytes());
ImageIO.write(newImage, "png", destFile);
result.put("success", true);
// result.put("url", path + pre +
// file.getOriginalFilename().toLowerCase());
result.put("url", path + pre + fileType);
} catch (IOException e) {
result.put("success", false);
e.printStackTrace();
}
}
} else {
result.put("success", false);
}
return result;
}private  BufferedImage  getNewImage(MultipartFile oldImage,double width,double height) throws IOException{
/*srcURl 原图地址；deskURL 缩略图地址；comBase 压缩基数；scale 压缩限制(宽/高)比例*/

ByteArrayInputStream bais = new ByteArrayInputStream(oldImage.getBytes());
MemoryCacheImageInputStream mciis = new MemoryCacheImageInputStream(bais);
Image src = ImageIO.read(mciis);
double srcHeight = src.getHeight(null);
double srcWidth = src.getWidth(null);
double deskHeight = 0;//缩略图高
double deskWidth  = 0;//缩略图宽
if (srcWidth>srcHeight) {

if (srcWidth>width) {
if (width/height>srcWidth/srcHeight) {
deskHeight = height;
deskWidth = srcWidth/(srcHeight/height);
}
else {
deskHeight = width/(srcWidth/srcHeight);
deskWidth = width;
}
}
else {

if (srcHeight>height) {
deskHeight = height;
deskWidth = srcWidth/(srcHeight/height);
}else {
deskHeight=srcHeight;
deskWidth=srcWidth;
}

}

}
else if(srcHeight>srcWidth)
{
if (srcHeight>(height)) {
if ((height)/width>srcHeight/srcWidth) {
deskHeight = srcHeight/(srcWidth/width);
deskWidth = width;
}else {
deskHeight = height;
deskWidth = (height)/(srcHeight/srcWidth);
}
}
else {
if (srcWidth>width) {
deskHeight = srcHeight/(srcWidth/width);
deskWidth = width;
}else {
deskHeight=srcHeight;
deskWidth=srcWidth;
}

}

}
else if (srcWidth==srcHeight) {

if (width>=(height)&&srcHeight>(height)) {
deskWidth=(height);
deskHeight=(height);
}
else if (width<=(height)&&srcWidth>width) {
deskWidth=width;
deskHeight=width;
}
else  if (width==(height)&&srcWidth<width) {
deskWidth=srcWidth;
deskHeight=srcHeight;
}
else {
deskHeight=srcHeight;
deskWidth=srcWidth;
}

}
BufferedImage tag = new BufferedImage((int)deskWidth,(int)deskHeight,
BufferedImage.TYPE_3BYTE_BGR);
tag.getGraphics().drawImage(src, 0, 0, (int)deskWidth, (int)deskHeight, null); //绘制缩小后的图
return tag;
}