2.將pdf解壓，放入專案中webapp下

3.後臺處理：根據url獲取pdf，把資料寫入到輸出流

    js：

download: function (url) {
    var urls = '${contextPath}/***/open?urls='+url;
window.location.href = "${ctxStatic}/pdf/web/viewer.html?file="+encodeURIComponent(urls);
},

    後臺：

@RequestMapping(value = "/open",method = RequestMethod.GET)
public void open
 
(String urls,HttpServletResponse response) throws IOException {
    URL httpUrl=new URL(urls);
HttpURLConnection httpURLConnection=(HttpURLConnection) httpUrl.openConnection();
InputStream inputStream=httpURLConnection.getInputStream();
response.setHeader("Content-disposition", "attachment; filename=" 
 
+ new String( "PDF檔名".getBytes("gb2312"), "ISO8859-1" ) );
response.setContentType("multipart/form-data");
OutputStream outputStream = response.getOutputStream();
IOUtils.write(IOUtils.toByteArray(inputStream),outputStream);
}