jsp页面上传文件，下载文件，设置下载文件格式和预览文件

<tr height="35px">
	<td width="25%" height="20px" align="right">添加回款记录：</td>
	<td width="75%" height="20px" align="left">
	<input class="easyui-filebox" data-options=" buttonText: '选择文件',prompt:'浏览'"  multiple="true" id="addFile" name="file" style="width:90%" onchange="checkFile()" />
	</td>
</tr>

//easyui 文件框
	$('#addFile').filebox({
    buttonText: '选择文件',  //按钮文本
    buttonAlign: 'right',   //按钮对齐
    //multiple: true,       //是否多文件方式
    onChange: function (e) {
    checkFile();
    }
 });

 //控制上传文件格式
function checkFile(){
	var fileTypes = ['.jpg', '.jpeg', '.bmp', '.png', '.gif','.pdf'];
	var filePath = $('#addFfile').textbox('getValue');
	if (filePath != '')
	{
	    var flag = false;
		var fileType = filePath.substring(filePath.lastIndexOf("."));
		if(fileTypes && fileTypes.length>0){
			for (var i = 0; i < fileTypes.length; i++){
			　　if(fileTypes[i]==fileType){
			　　　　flag = true;
			　　　　　break;
			　　　　}
			　　　}
			　}if (!flag) {
			　　alert('不接受'+fileType+'文件类型上传');
			　　　$('#addFfile').textbox('setValue', '');
			　　　　return;
			　　　　}
			　　}
			}

formatter : function(value, row, index) {
    return ('<a data-index="' + index + '"  class="chakan"><button type="button" class="download">文件下载</button></a> <a data-index="' + index + '"  class="yulan"><button type="button" class="search">文件预览</button></a>');
}

/**
	  * 文件下载 downAttachment
	  * @throws IOException 
	  */
	 @RequestMapping(value = "/downLoadAttachment",produces = "application/octet-stream;charset=UTF-8",method = RequestMethod.GET)
	 @ResponseBody
	 public ResponseEntity<byte[]> downAttachment(HttpServletRequest request,
	   @RequestParam("filename") String filename,
	   @RequestParam("path") String path) throws IOException {
	   //下载文件路径
	   path = uploadDir +"\\"+path;
	   File file = new File(path);
	   if(!file.exists() || file.length() == 0) {  
	       System.out.println("文件为空！");  
	   }else{ 
	    HttpHeaders headers = new HttpHeaders();
	    //下载显示的文件名，解决中文名称乱码问题
	    String downloadFielName = null;
	    String useragent = request.getHeader("USER-AGENT").toLowerCase();
	          if(useragent.contains("msie")||useragent.contains("like gecko")||useragent.contains("trident")){  
	          //ie11或者win10中用户代理字符串已经修改了，不再是“msie”了，添加了like Gecko，所以加上like gecko判断
	           downloadFielName = URLEncoder.encode(filename , "UTF-8");
	          }else{
	           downloadFielName = new String(filename.getBytes("utf-8"),"iso-8859-1"); 
	          }
	    //通知浏览器以attachment（下载方式）打开图片
	    headers.setContentDispositionFormData("attachment", downloadFielName);
	    //application/octet-stream ： 二进制流数据（最常见的文件下载）。
	    headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
	    return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);
	   }
	   return null;
	 }

var gridPanel = datagrid.datagrid("getPanel");
gridPanel.on("click", "a.chakan", function() {
	var rows = datagrid.datagrid('getSelections');
	var id = rows[0].id;
	var fileName = rows[0].fileName;
	var filePath = rows[0].filePath;
	var fileName = encodeURIComponent(fileName);
	var filePath = encodeURIComponent(filePath);   window.location.href="${ctx}/file/downLoadAttachmentfilename="+fileName+"&path="+filePath;
})

formatter : function(value, row, index) {
    return ('<a data-index="' + index + '"  class="chakan"><button type="button" class="download">文件下载</button></a> <a data-index="' + index + '"  class="yulan"><button type="button" class="search">文件预览</button></a>');
}
								}

<div id="imageDiv" class="easyui-dialog" style="display:none;" closed="true">
	<img id="imag" alt="" src="">
</div>

.on("click", "a.yulan", function() {
	var rows = datagrid.datagrid('getSelections');/*获取选中行的数据*/
	var filePath = rows[0].filePath;
	/* jsp url转义 */
	filePath = encodeURIComponent(filePath);
	$("#imag").attr("src","${ctx}/salesDetails/previewPeacher?filePath="+filePath); 
		var win = $('#imageDiv').dialog({ //创建弹出框
		width : '90%',
		height : '100%',
		modal : true, //遮罩层
		title : '文件预览',
		shadow : true, //阴影
		    buttons : [ {
				text : '关闭',
				iconCls : 'icon-no',
				handler : function() {
					$("#imageDiv").dialog('close');
				}
			}]
		});
			win.dialog('open'); //打开添加对话框
			win.window('center'); //使Dialog居中显示
		})

/**
 * 图片预览
 * @param request
 * @param response
 * @param filePath
 * @throws IOException
 */
@RequestMapping("/previewPeacher")
public void getImg2(HttpServletRequest request, HttpServletResponse response,String filePath ) throws IOException {
	FileInputStream fis = null;
	OutputStream os = null;
	try {
		fis = new FileInputStream("D:\\hyzn\\"+filePath);
		os = response.getOutputStream();
		int count = 0;
		byte[] buffer = new byte[1024 * 8];
		while ((count = fis.read(buffer)) != -1) {
		os.write(buffer, 0, count);
		os.flush();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			try{
			    fis.close();
				os.close();
			}catch (Exception e) {
				e.printStackTrace();
			}
		}
    }