（三）上传后显示：
1，上传后用js从上传控件获取数据显示，用于时时看效果不必保存图片后再从磁盘拿
<label>上传图片：</label> <span><input type="file"
style="width: 240px; border: none;" accept=".jpg,.gif,.png,.bmp"
name="picture" value="${vo.picture_address}"
onchange="previewImage(this,'preview','imghead')" /></span> <br>//页面上控件拿
<div id="preview">
<img id="imghead"
src="${pageContext.request.contextPath}${vo.picture_address}"
alt="" style="cursor: pointer; width: 100%;" />//磁盘拿
</div>
function previewImage(file, preview, imghead) {
var MAXWIDTH = 260;
var MAXHEIGHT = 180;
var div = document.getElementById(preview);
if (file.files && file.files[0]) {
div.innerHTML = "<img id='"+imghead+"'>";
var img = document.getElementById(imghead);
img.onload = function() {
var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT,
img.offsetWidth, img.offsetHeight);
img.width = rect.width;
img.height = rect.height;
// img.style.marginLeft = rect.left+'px';
img.style.marginTop = rect.top + 'px';
}
var reader = new FileReader();
reader.onload = function(evt) {
img.src = evt.target.result;
}
reader.readAsDataURL(file.files[0]);
} else //兼容IE
{
var sFilter = 'filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
file.select();
var src = document.selection.createRange().text;
div.innerHTML = "<img id='"+imghead+"'>";
var img = document.getElementById(imghead);
img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth,
img.offsetHeight);
status = ('rect:' + rect.top + ',' + rect.left + ',' + rect.width
+ ',' + rect.height);
div.innerHTML = "<div id=divhead style='width:"+rect.width+"px;height:"+rect.height+"px;margin-top:"+rect.top+"px;"+sFilter+src+"\'></div>";
}
}
function clacImgZoomParam(maxWidth, maxHeight, width, height) {
var param = {
top : 0,
left : 0,
width : width,
height : height
};
if (width > maxWidth || height > maxHeight) {
rateWidth = width / maxWidth;
rateHeight = height / maxHeight;
if (rateWidth > rateHeight) {
param.width = maxWidth;
param.height = Math.round(height / rateWidth);
} else {
param.width = Math.round(width / rateHeight);
param.height = maxHeight;
}
}
param.left = Math.round((maxWidth - param.width) / 2);
param.top = Math.round((maxHeight - param.height) / 2);
return param;
}
2，上传后从后台显示，需要保存后再从磁盘拿
@RequestMapping(value = "/system/tbBasBed/showImage")
public void showReportImage(@RequestParam(value = "imageType") String imageType,
@RequestParam(value = "id") String id,
HttpServletRequest request,HttpServletResponse response) throws IOException, NumberFormatException, EsteelException {
// response.setContentType("image/jpeg");
response.setCharacterEncoding("UTF-8");
// String filePath= WebConfig.get("filePath");
String path = WebConfig.get("filePath") ;
File file=null;
TbBasBed currbasBed = new TbBasBed();
currbasBed.setWare_key(id);
currbasBed= tbBasBedService.getBasBedById(Integer.valueOf(id+""));
if(currbasBed!=null){
if("bas".equals(imageType)&&currbasBed.getPicture_address()!=null){
file=new File(path+currbasBed.getPicture_address());
}
}
if( file==null||!file.exists()){
response.getWriter().print("未找到图片");
}else {
response.setContentType("image/jpeg");
FileInputStream fos = new FileInputStream(file);
byte[] bytes = new byte[1024*1024];
int length = 0;
while((length=fos.read(bytes))!=-1){
response.getOutputStream().write(bytes,0,length);
}
}
}