java web显示pdf_javaWeb项目实现pdf预览

本来是想做下载，结果无意中发现response不设置头部即可实现预览，此代码也可直接实现 照片，word文档等预览。

前端代码：

注意： target="_black 可以让pdf在新的网页打开。

预览

后端代码：

@WebServlet(name = "DownLoadPdf")

public class DownLoadPdf extends HttpServlet {

protected void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException {

String fileName = request.getParameter("fileName");

if(fileName!=null){

String realPath = request.getSession().getServletContext().getRealPath("/attachFiles/detections/");

File file = new File(realPath+fileName);

FileInputStream fis = new FileInputStream(file);

ServletOutputStream out = response.getOutputStream();

byte[] buf = new byte[4096];

int len = -1;

while ((len = fis.read(buf)) > 0) {

out.write(buf, 0, len);

}

out.flush();

fis.close();

out.close();

}

}

}

若要进行下载，则加入以下代码。

response.setHeader("Content-Disposition", "attachment; filename=\""

+ fileName + "\"");

response.addHeader("Content-Length", file.length() + "");

response.setContentType("application/octet-stream");